Technical Introduction...TECHNICAL INTRODUCTION SHINKO WELDING SERVICE CO., LTD. - 2 - 3. Technical...

TECHNICAL INTRODUCTION

SHINKO WELDING SERVICE CO., LTD.

- 2 -

3. Technical Details

3.1 Test and Investigation

3.1.1 Analysis and Test

(1) Chemical analysis

By making full use of various analytical methods and latest equipments, we meet all sorts of your needs for

analyses.

[Wet Chemical Analysis]

In the wet chemical analysis, traditional chemical analysis, particular

analytical methods (e.g. volumetric method, gravimetric method, and

absorptiometric method) are selected depending on the composition of

the specimen. Although they take much time and use specific

techniques, they offer high accuracy. They are applied for elemental

analysis (C, Si, Mn, P, S, etc.) of steels such as carbon steels and

special steels and nonferrous metals such as aluminum alloys and

copper alloys, and for component analysis of minerals such as limestone

and feldspar.

[Inductively Coupled Plasma-Optical Emission Spectrometric Analysis]

In this method, an intrinsic spectral line of each element is measured

by spraying a solution specimen on high-temperature argon plasma to

excite each element for emission and spectral diffraction. This method

offers high sensitivity (possible for a low ppm-concentration level

analysis) and accuracy, comparable to chemical analysis. This method is

used for elemental analysis of steels and nonferrous metals, which is

capable of analyzing As, Se, and Sb, too.

[Combustion-Infrared Absorption Analysis]

In this method, a chipped sample is put in a porcelain crucible and is

fused by heating in oxygen atmosphere to generate the gas. This gas is

measured by infrared-absorption analysis. This method is applied for

the analysis of C and S in steels, nonferrous metals, and minerals.

[Photoelectric Photometry Emission Spectral Analysis]

In this method, the intrinsic spectral line of each element is

measured for analysis by generating the spark discharge between the

surface of solid specimen and the electrode for spectral diffraction. This

method offers short analytical time and can be applied for elemental

analysis of carbon steels and low alloy steels.

[X-ray Fluorescence Spectrometry (Wavelength Dispersive Method)]

In this method, by irradiating X-ray on a specimen, the secondary

X-rays having intrinsic wavelengths of elements are measured for

analysis. With this method, such various forms of specimens as solid,

powder, and liquid can be measured. This method can be applied for

qualitative analysis of solids and powders whose components are

unknown, and for confirmation analysis of steel wires and rods.

- 3 -

[Gas Chromatography]

In this method, a gaseous sample or a sample evaporated from a

liquid is sent into the column filled with a carrier gas like He and Ar.

By utilizing that the speed of passing through the column depends on

the ingredients of the gases of the sample, the ingredients of the gases

can be separated for quantitative and qualitative analyses. According

to the detection method of separated gases, this method can be

classified as Gas Chromatography-Mass Spectroscopy (GC-MS), Gas

Chromatography-Thermal Conductivity Detection (GC-TCD), and

Gas Chromatography-Flame Ionization Detection (GC-FID). They are

suitable for analyzing multicomponent mixtures of organic compounds.

[Temperature Rising-Style Hydrogen Analysis]

In this method, a specimen is heated at a preset heating rate to

extract gases for measurement by means of Mass Spectrometer. The

hydrogen remained by various mechanisms is separated to measure as

a function of temperature. In addition, gases other than hydrogen can

also be measured by changing the measuring molecular weights for

Mass Spectrometer.

[Ion Chromatography]

In this method, a sample solution is passed through the column filled with ion exchange resin in order to separate each ion by utilizing the differences of affinity for the resin. The separated ions are measured by an electric conductivity detector, the ion components are identified by the peak positions and the ingredient amounts are determined by the peak areas. Anions of inorganic and organic substances, cations of alkali metals, alkali-earth metals and ammonium in solutions can be analyzed.

[Other Chemical Analysis Methods]

In addition to the above-mentioned chemical analysis methods, we make use of Atomic Absorption

Spectrometry, Moisture Analysis by Karl Fischer Method, Simultaneous Analysis of Oxygen and Nitrogen,

Measurement of Diffusible Hydrogen, Ozone Analysis, and Fourier Transform Infrared Spectrometry

(FT-IR).

(2) Material Test

We conduct various evaluation tests for strength, hardness, wear

resistance of materials, as discussed in the following.

[Tensile/Compression Test]

This testing is to evaluate material strengths such as yield strength,

tensile strength and elongation after fracture by applying loads on

specimens. The capacities of testing machines range from 20 kN to

1000 kN (2 tf to 100 tf) for tensile, compression and bend tests.

[Charpy Impact Test]

This testing is to evaluate the toughness (ductility) of materials by

applying impact load on a notched specimen by using the hammer. The

testing temperatures range from low, room, to elevated temperatures.

The JIS- and ASTM-specified testing machines are available.

- 4 -

[Creep Test]

In this test, a particular constant load is applied on a specimen

held at elevated temperature in the furnace for a long term. The

strain (%) and the time to rupture under the applied stress are

measured to know the creep strength. The creep test can be

conducted at various temperatures from room temperature to

about 800 ℃.

[Hardness Test]

In this test, the hardness of a specimen can be determined by

measuring the area or depth of the dent which is made by pressing

the quadrangular pyramid or spherical indenter on the surface of a

specimen with the testing load suitable for the testing materials

and purposes. Vickers, Rockwell, Brinell, and Shore hardness

testers are available.

[Soil Abrasion Test]

In this test, a specimen is pressed onto a rotating rubber wheel

where silica sands are applied in the contacting area between the

wheel and the specimen, and the weight loss of the specimen is

measured to know its abrasion resistance.

[High-Temperature Friction Wear Test]

In this test, two specimens are pressed each other and are

rotated in the opposite direction against the other specimen to

know the degree of wear, thereby evaluating the friction wear

resistance. The testing temperature ranges from room temperature

to about 800 ℃.

[Other Material Tests]

In addition to the above-mentioned material tests, we can conduct such various tests as fatigue test,

CTOD (COD) test, and drop-weight test.

(3) Physics and Physical Properties Tests

With the following testing methods, the state of a particular substance can be clarified by measuring a

slight change against the physical reactions or by observing the minute particular area of a substance.

[Analysis with X-Ray Diffractometry (Powder Method)]

In this test, characteristic X-ray is irradiated on a specimen of

crystal powder, and the diffracted X-rays are measured. From the

measurement results, the information of the crystal structure of the

specimen can be obtained. Specifically, this analysis is used for the

identification of substances.

- 5 -

[Observation by Scanning Electron Microscope (SEM, FE-SEM)]

In this test, the surface of a specimen is scanned with an electron

beam, and the secondary electrons generated from the specimen are

detected to observe the specimen surface at a high magnification. By

measuring the X-rays generated from the spots where electron beams

are irradiated, qualitative and semiquantitative analysis of elements can

also be made. Besides, crystal orientation can be measured by means of

Electron Backscattering Diffraction (EBSD) image by Field Emission

Scanning Electron Microscopy (FE-SEM).

[Electron Probe Micro Analysis (EPMA)]

Like SEM and FE-SEM, qualitative and semiquantitative analyses can be conducted by scanning the

surface of a specimen with an electron beam. The analytical function is more complete than that of SEM

and thus“the mapping analysis”that shows the distributions of many elements in a particular area can be

conducted.

[Electron Spectroscopy for Chemical Analysis (ESCA)]

In the ESCA analysis, soft X-rays are irradiated on a specimen to detect the energy of photoelectrons

generated from the spot irradiated, and thereby it can be revealed what elements (ranging from Li to U)

exist in what state of binding and in what concentration transition into the depth direction. Because the

ESCA analysis detects photoelectron discharged only from the surface of the specimen to a few nm in

depth, it can obtain information only on ultra-thin layers of the surface that cannot be analyzed by EPMA.

Color-mapping analysis of

a gear tooth (X-ray image

of carbon)

EBSD crystal orientation analysis of a section of stainless steel weld

〔ＳＥＭ image (Brittle fracture)〕

951001051100

0.5

1

1.5

2

2.5

3x 10

4 check11.spe

Binding Energy (eV)

c/s

Si-metalSi-oxideSi-oxide Si-metal

Binding energy （eV)

[Results of state analysis of Si oxide and metallic Si]

Spec

tral

in

tensi

ty（C

/S)

- 6 -

[Measurement of Transformation Temperature]

By heating or cooling a metallic specimen at a programmed rate,

the phase transformation behavior (e.g. austenite-ferrite

transformation) of the specimen can be measured. Such special

test conditions as subzero treatment can also be supported.

[Observation of Macrostructure and Microstructure]

In this test, the surface of a solid specimen is polished flat and is etched with etchant like acid solution

to observe the metallic structure of the specimen. The magnification ranges from several to about 1000

times.

[Other Physics and Physical Properties Tests]

In addition to the above-mentioned tests, other various tests can be conducted by using the following

technologies: Transmission Electron Microscopy (TEM), Thermomechanical Analysis (TMA), Measurement

of Surface Roughness, Laser Electron Microscopy, Measurement of Specific Surface Area, Differential

Thermal Analysis (Differential Scanning Calorimetry), Analysis by Image Analysis Equipment, Measurement

of Fine Particle by Laser Zeta Electrometer, and Measurement of Corrosion Potential by Potentiostat.

(4) Nondestructive Test

Various materials, equipment, and welded constructions can be tested to detect surface flaws, internal

defects, welding imperfections, and damages, without cutting, disassembling, and damaging the properties

and performance of the testing specimen. We contract for Radiographic Test, Ultrasonic Test, Magnetic

Particle Test, Dye Penetrant Test, as well as Visual Examination.

(5) Welding Test

We contract for all sorts of tests concerning the welding of steels, nonferrous metals, and nickel-based

superalloys.

[Weld Cracking Test]

We contract for the following various cracking tests to examine the crack susceptibility of welds.

[Examples of weld cracking tests]

Test JIS Standard Content

y-Groove Weld Cracking Test JIS Z 3158 • Testing of cold crack susceptibility of weld and heat-affected zone in

the root pass weld of steels

Window Type Restraint Weld

Cracking Test -

• Testing mainly of cold crack susceptibility of weld and heat-affected

zone

FISCO Test JIS Z 3155 • Testing of hot crack susceptibility of weld

Varestraint Crack Test - • Testing of hot crack susceptibility by giving bending deformation

instantaneously to a test specimen being welded

We also contract for the following tests: U-Groove Weld Cracking Test, Underbead Cracking Test, H-

Type Restrained Weld Cracking Test, Fillet Weld Cracking Test, and Cranfield-Type Cracking Test

〔Microstructure of gray cast iron 〕

- 7 -

[Measurement of Welding Characteristics]

We contract for various tests concerning welding workability and welding efficiency as follows:

① Measurement of Fume Emission Rate

② Measurement of Spatter Generation Rate

③ Measurement of Deposition Rate and Melting Rate

[Other Tests]

We contract for various tests shown in the table below for

evaluating various kinds of weld metals and weld joints and for

testing welding thermal cycle. We also contract for mechanical

tests for welding procedure tests to obtain approvals of official

inspection organizations like classification societies. Besides,

we contract for various welding tests using the

temperature-humidity controlled room at a range from -40 ℃

to +50 ℃.

[Various welding-related evaluation tests] Item Contents

Evaluation Test for Weld Metal

• Chemical Analyses • Material Tests (Tension, Bend, Impact, and Hardness, etc.) • Measurement of Hydrogen Volume (Diffusible hydrogen, Residual hydrogen) • Corrosion Test • Wear Test

Evaluation Test for Weld Joint

• Material Tests (Tension, Bend, Impact, and Hardness, etc.) • Fatigue Test • Creep Test • Fracture Toughness Test (CTOD Test, Drop-Weight Test) • Inspection of Defects (X-Ray Test, Ultrasonic Test, Magnetic Particle Test, Dye Penetrant Test, etc.)

• Hydrogen Disbonding Test • Measurement of Welding Strain and Residual Stress

Test of Weld Thermal Cycle

• Synthetic Heat-Affected Zone Test

(6) Corrosion Test

We contract for various corrosion tests for all sorts of metallic and surface-treated materials, including

the following corrosion tests for stainless steels according to the JIS standard as shown in the table below.

[Examples of corrosion tests] Test JIS

Standard Purpose Measuring Item

Oxalic Acid Etch Test for Stainless Steels

G 0571

• To judge the necessity for various hot corrosion tests

• Etching state of grain boundaries (step-like structure, mixed structure, groove-like structure)

• Pitting state Ferric Sulfate-Sulfuric Acid Test for Stainless Steels

G 0572 • To test the degree of

intergranular corrosion • Corrosion loss

65% Nitric Acid Test for Stainless Steels


intergranular corrosion • Corrosion loss

Copper Sulfate-Sulfuric Acid Test for Stainless Steels


intergranular corrosion • Crack occurrence by intergranular

corrosion after bend testing Stress-Corrosion Cracking Test for Stainless Steels

G 0576

• To confirm corrosion resistance

• To test stress-corrosion cracking susceptibility

• Time for crack generation • Crack-crossing time or rupture time

Pitting Potential Measurement for Stainless Steels

G 0577 • To confirm pitting corrosion

resistance • Pit initiation potential (The lower the potential, the lower the corrosion resistance)

〔Temperature-humidity controlled room〕

- 8 -

3.1.2 Investigation and Research

(1) Investigation of Materials

In response to requests from customers such as enterprises, research institutes and universities, we

contract for investigation of material damages and for evaluation of materials to deal with solving issues on

metallic materials, welds and joints. Our investigation and research are intended for such field as heavy

electric, industrial machinery, chemical machinery, building, and bridge industries. Our technologies are

highly reputed to be the top-ranking in Japan as regards the investigation of materials and welds. [Investigation of damages]

For investigation into causes of such troubles as damages, wear, cracks, and corrosion occurred in metallic materials and welds, we use a Scanning Electron Microscope (SEM), an Electron Probe Micro Analyzer (EPMA), a Transmission Electron Microscope (TEM), and an Electron Spectroscopy for Chemical Analysis (ESCA). We report to the customers not only the investigation results but also preventive measures. [Evaluation of material]

With a Field Emission Scanning Electron Microscope (FE-SEM), a Transmission Electron Microscope (TEM), we have been conducting material evaluation for metallic materials and welds in terms of crystal orientation, lattice defect, and state of precipitation. We provide clients with reports useful for research and development of metallic materials, welding consumables and so on. [Examples of damage investigation and material evaluation results]

As shown in the table below, we have carried out various investigations into damages such as fatigue

fracture, stress corrosion cracking, and hot cracking. We have experienced much in material evaluation

including micrography of the duplex stainless steel weld structure by means of TEM and analysis of the

crystal orientation of stainless steel weld structure by means of FE-SEM/EBSD.

[Examples of damage investigations]

Classification Content Type of industry Object Material

Damage Fatigue fracture caused by a surface defect in a material

Industrial machinery Bench spring (Robot) Spring steel

Damage Fatigue fracture caused by inclusions in a material

Industrial machinery Compressor Swedish steel

Damage Corrosion fatigue initiated in a weld Chemical machinery Centrifugal separator Stainless steel

Damage Corrosion fatigue initiated in a weld Industrial machineryAgitator shaft (Water treatment equipment)

Stainless steel

Damage Fatigue fracture of a bolt Building Bolt Carbon steel

Damage Ductile fracture of a weld Industrial machinery Crane Carbon steel

Crack Hot crack in a weld Electric equipment Electric part Carbon steel

Crack Creep crack in a weld Chemical machineryPiping (Petroleum refining equipment)

Stainless steel

Crack Stress corrosion cracking in a weld Chemical machinery Piping (Chemical plant) Stainless steel

Leakage Water leakage caused by crevice corrosion in penetration welds

Industrial machinery Water treatment tank Stainless steel

Leakage Process liquid leakage caused by crevice corrosion in penetration welds

Heavy electric equipment

Piping Stainless steel

Leakage Helium leakage caused by inclusions in a material

Aircraft Valve Stainless steel

(2) Research on Joining

In response to requests from research institutes of enterprises and independent administrative

corporations, we investigate and research on welding and joining processes, dealing with “research on

new joining processes”, “consultation on the welding and joining procedures (e.g. selection of proper

conditions)” and “consultation on the welding and joining problems” .

The materials we deal with include carbon steel, special steels (heat-resistant steel and stainless steel),

- 9 -

and nonferrous metals (aluminum alloy, titanium alloy, and niobium alloy). The welding processes we deal

with include arc welding, laser welding, hybrid laser-arc welding, friction stir welding (FSW), electron beam

welding, and ultrasonic welding. We consult also on dissimilar material welding and repair welding.

The types of industries we deal with include many fields such as the automobile, rolling stock, heavy

electric and electronic equipment industries. In cooperation with universities and enterprises, we have

been investigating and supporting researches on the joining technologies as national projects. These

research results are presented at academic meetings and led to patent acquisition and press release.

[Examples of welding and joining researches]

As shown in the table below, we have been engaged in the consultation on a large number of researches

for establishing welding procedures and evaluating the properties of welds. The fields we deal with include

non-arc welding processes such as laser welding and electron beam welding of carbon steels, special steels,

and nonferrous metals for the automobile and heavy electric industries.

[Examples of welding and joining researches]

Consultation item Type of industry

Material Welding process

MIG welding for steel-aluminum dissimilar metal

Automobile Steel and aluminum alloy

MIG welding

Laser welding of sintered powder material

Automobile Sintered iron powder material

Laser welding

Crack prevention of laser weld of high tensile strength steel

Automobile High tensile strength steel

Laser welding

Electron beam welding of stainless steel

Heavy electric Stainless steel Electron beam welding

Spot FSW for steel-aluminum dissimilar metal

Automobile Steel and aluminum Friction stir welding

MIG welding for lining of titanium Offshore structure

Titanium and steel MIG welding

TIG welding of titanium and niobium Heavy electricTitanium alloy and niobium alloy

TIG welding

TIG welding of titanium parts Automobile Titanium alloy TIG welding

Welding and joining

TIG welding of stainless steel vessel Heavy electric Stainless steel TIG welding Repair welding of die steel Automobile High carbon steel TIG welding

Repair welding of Cr-Mo steel Heavy electric Heat-resistant steel Shielded metal arc welding

Repair welding

Repair welding of forged metal mold Metal mold Heat-resistant steel MAG welding Surface modification

Hardening technique for titanium alloy

Tool, Heavy electric

Titanium alloy TIG welding Laser welding

[Various new joining processes]

Solid state welding

utilizing friction heats Junction tool

（Rotating pin）

Friction Stir Welding （FSW）

レー

ザアー

ク

アー

ク

レー

ザ Arc

Laser

Molten pool

Hybrid laser-arc welding

- 10 -

3.1.3 Production of welding consumables and testing specimens

To respond to customer requests of outsourcing for research and development, we contract for

production of experimental welding consumables and testing specimens.

(1) Production of experimental welding consumables

We produce various welding wires for welding tests in our production line that consists of melting (in

atmosphere or in vacuum), drawing, and plating to finish products. These products include wires for MIG

welding, TIG welding, CO2 welding, and laser welding. We also take up rolling and drawing of steel ingots

supplied from customers to produce wires with customer-specified diameters. As regards experimental

products (incl. improving products) of Kobe Steel, Ltd., they deal with by themselves.

(2) Production of welding test specimens

We produce testing specimens in accordance with various welding procedures, which include specimens

for confirmation test and cracking test. Besides, we can conduct welding in the temperature-humidity

controlled room (See Page 7) when needed.

[Production procedures for welding test specimens] Contents Production procedure

Welding joining processes

・Shielded metal arc welding ・MAG, MIG welding ・Submerged arc welding ・Electrogas arc welding ・Electroslag welding ・TIG welding ・Strip overlaying

Materials

・Carbon steels, Low alloy steels, High alloy steels ・Aluminum and aluminum alloys ・Nickel alloys ・Copper alloys ・Cast irons, Cast steels

Main equipments available

・Arc welding robots ・AC arc welding machines ・DC arc welding machines ・Various automatic welding machines

(3) Production of welding defect specimens

We produce weld specimens that contain various welding

defects that are artificially occurred during and after welding.

They are available for teaching materials and for checking

the difference between nondestructive tests, the consistency

of NDT and the detection accuracy of NDT. The welding

defect specimen can contain such welding defects as cracks,

blowholes, incomplete fusions, slag inclusions and lack of

penetration.

[Example of welding defect specimen]

[Vacuum melting furnace (Capacity: 30 kg)]

[Arc welding robot]

ブローホール

割れ

融合不良

Cracks

Lack of fusion

Blowholes

- 14 -

3.4 Welding training

Sound welding can start with bringing up competent engineers and skilled technicians. When it comes to

welding training, please count on us because we have been experienced for more than half a century. Our

first-class welding personnel who are experienced in the welding training will instruct participants

effectively not only in skill, but also in knowledge.

[Content of training]

We have various training courses including a preparation course for taking“Assessment Test for JIS

Welding Technicians (JIS official approval)”for which about 100,000 applicants make efforts for the

challenge in Japan every year, a skill and knowledge acquisition course for welding aluminum alloy and

titanium alloy which are widely used increasingly and a certification acquisition course for such nonferrous

alloys for JIS Welding Technicians. We run the preparation course for the JIS Test every month, in which

300 applicants participate yearly. Of these applicants the acceptance ratio is about 90%. We take up any

made-to-order courses such as a training course for new employees for each enterprise, and an improving

course for skilled workers on welding knowledge and skill.

[Contents of training courses]

Type of course Contents

Regular course

・Preparation course for taking the Assessment Test for JIS Welding Technicians

・Introduction course for welding

・Basic course for TIG welding

・TIG welding course for stainless steels, aluminum alloys, and titanium alloys

・Fresh salesperson course

Flexible course

・Practice and verification course on basic welding techniques

・Improving course for practical welding skill

・General and special boiler welder course

・WES 8103 course for welding supervising engineer

[Lecture with textbooks and videos]

[Practical training for semi-automatic welding〕

- 15 -

4. Main Tests and Investigations

Item No. Content

(1) Analysis by Gas Chromatography-Mass Spectrometry

(2) Thermal analysis of hydrogen

(3) Analysis by Ion Chromatography

(4) Measurement of Diffusible Hydrogen Content

Chemical analysis

(5) Analysis by Fourier Transform IR (FT-IR)

(6) Tensile Test

(7) Charpy Impact Test

(8) Creep Test

(9) Hardness Test

(10) Dry Sand / Rubber Wheel Abrasion Test

(11) High Temperature Friction Wear Test

(12) CTOD Test

Material test

(13) Drop-Weight Test

(14) X-ray Diffraction Test

(15) Observation by Scanning Electron Microscope (SEM)

(16) Observation by Field Emission Scanning Electron Microscope (with EDS/EBSD)

(17) Electron Probe Micro Analysis (EPMA)

(18) Electron Spectroscopy for Chemical Analysis (ESCA)

(19) Measurement of Transformation Temperature

(20) Observation of Macrostructure and Microstructure

(21) Observation by Transmission Electron Microscopy (TEM)

(22) Thermal Analysis

(23) Measurement of Surface Roughness

Physics and physical properties test

(24) Image Analysis

Nondestructive test (25) Nondestructive Test

(26) y-Groove Weld Cracking Test

(27) Varestraint Cracking Test

(28) Measurement of Welding Fumes

(29) Measurement of Welding Spatters

Analysis and test

Welding test

(30) Measurement of Welding Strain and Residual Stress

(31) Example-1 of Damage Investigations (Fatigue Fracture)

(32) Example-2 of Damage Investigations (Stress Corrosion Cracking)

(33) Example-3 of Damage Investigations (Hot Crack)

(34) Example-1 of Material Evaluations (TEM Micrography of Structures)

Material investigation

(35) Example-2 of Material Evaluations (Analysis of Crystal Orientation by EBSD)

(36) Example-1 of Researches on Welding and Joining (Scrum-Rivet MIG Welding of Steel and Aluminum

(37) Example-2 of Researches on Welding and Joining (Laser Welding Technology for Iron Powder Sintered Parts)

Research for welding and joining

(38) Example-3 of Researches on Welding and Joining (Technology for Direct Lining of Titanium on Steel Plates)

- 16 -

(1) Analysis by Gas Chromatography-Mass Spectrometry

＜Outline＞

The gas chromatography-mass spectrometry is an analytical method, in which a gas chromatographic

detector and a mass-analyzer are combined. This method can identify compositions and measure their

amounts contained in organic compounds. A measuring specimen is separated into different substances

which have different masses by using the gas chromatographic detector. With this apparatus, only gases

can be separated, hence it is necessary to volatize or to gasify non-gaseous substances. Then the

mass-analyzer measures the mass numbers of the separated substances to identify them. The measurement

of a particular substance is obtained from the peak area detected by the chromatographic detector.

＜Applicable specimens＞

・ Organic compounds

・ Gases and smokes

・ Foods

＜Analyzable items＞

・ Constitutional compounds

・ Mass (Quantitative analysis

level is ppm)

＜Examples of applications＞

・ Analysis of gases in the air

・ Analysis of industrial liquid waste

・ Investigation of components in agricultural chemicals

・ Analysis of odorous components in foods

＜Main specifications of available equipment＞

・ Mass range：4-1000 ams

・ Resolving power：1600 (at a half value width of m/z614)

[Block diagram of GC-MS

[Mass spectrum of benzoic acid]

② Interface (IF) Ion that does not go straight

① Gas Chromatographer(GC)

Ion source

Column

Lens Ion detectorMass separator

Quadrupole electrode

③ Mass Spectrometer (MS)

Rel

ativ

e in

tensi

ty

Base peak

Benzoic acid

Molecular ion peak

Isotope peak

(Mass number/Electric charge)

- 17 -

(2) Thermal analysis of hydrogen

＜Outline＞

Steels and weld metals contain diffusible hydrogen and residual hydrogen. In welding of steels, the

hydrogen that can diffuse at around room temperature is called diffusible hydrogen, and the hydrogen that

cannot diffuse is called residual hydrogen. In this method, a specimen is heated at a constant heating rate

to extract gases for measurement by means of a Mass Spectrometer. The hydrogen remained by various

mechanisms is separated to measure as a function of temperature. In addition, gases other than hydrogen

can also be measured by changing the measuring molecular weights for the Mass Spectrometer.


・ All sorts of metallic materials


・ Relation between extracted hydrogen and holding time at a constant temperature

・ Relation between extracted hydrogen and temperature during heating at a preset rate


・ Measurement of diffusible and residual hydrogen in carbon steel or special steel deposited metals

・ Measurement of diffusible and residual hydrogen in steels, wire rods, and metal products

・ Analysis of nitrogen, oxygen, moisture and argon, besides hydrogen


・ Maximum size of specimen: 12-mm Thickness × 25-mm Width × 40-mm Height

・ Maximum heating temperature： 1000 ℃

・ Measurable range of Mass Spectrometer： Molecular weight of 2-200

ＱＭＳ： Mass Spectrometer for analyzing hydrogen

ＴＭＰ，ＲＰ： Vacuum pumps

Furnace

[Block diagram of thermal hydrogen analyzer]

Extracted peak of room-temp.

diffusible hydrogen

Hyd

roge

n io

n co

nce

ntr

atio

n (A

)

Temperature （℃）

Specimen

Solenoid valve

QMS

TMP

RS

Preparation room

TMP

RP

Extracted peak of residual

hydrogen

[Measurements of hydrogen in weld metal by

shielded metal arc welding]

Mild steelStainless steel

- 18 -

(3) Analysis by Ion Chromatography

＜Outline＞

The ion chromatography is suitable for analyzing anions of inorganic and organic substances and cations

of alkali metals, alkaline earth metals, and ammonium in solutions. The analyzable lower limit ranges from

several μg/L to several tensμg/L (1 μg/L: 0.000001g per 1 liter). In this method, a sample solution is

passed through a column filled with ion exchange resin in order to separate each ion by utilizing the

differences of affinity with the resin. The separated ions are measured by an electric conductivity detector,

the ion components are identified by the peak positions (time), and the ingredient amounts are determined

by the peak areas.


・ Inorganic cations and anions, and organic cations and anions in solutions


・ Qualitative analysis of various ions

・ Quantitative analysis of various ions


・ Analysis of the concentration of sulfuric acid ion in rain water

・ Analysis of ammonium in river and drainage

・ Analysis of chloride ions in concrete

・ Analysis of additives in foods

・ Analysis of corrosive elements in corrosion products of metals (Detection of chloride ions)


・ Ion Chromatograph： DX-120 made by DIONEX

Electric Conductivity Detector with a full scale of 1000μS

・ Auto sampler： AS50

・ Analyzing software： Peak Net

0 2.00 4.00 6.00 8.00 10.00 12.00 14.00 16.00

時間(分)

0

2.0

4.0

6.0

8.0

10.0

uS

1 - F

2 - Cl

3 - NO3

4 - SO4

Conduct

ivity

(μs)

1-F

2-Cl

Time (minute)

4-SO4

[Ion chromatography of tap water]

3-NO3

- 19 -

(4) Measurement of Diffusible Hydrogen Content

＜Outline＞

In steels and weld metals, there exists atomic hydrogen that can diffuse relatively freely through the

lattices at room temperature. This type of hydrogen is called diffusible hydrogen. The diffusible hydrogen

can cause cold cracks. For measuring the diffusible hydrogen in metals, the JIS Z 3118 specifies gas

chromatography and glycerol replacement method. With gas chromatography, a weld specimen is held in a

hydrogen sampling container at 45℃ for 72 h, and the extracted hydrogen is measured by using a gas

chromatograph. With glycerol replacement method, a weld specimen is put into a hydrogen sampling

container filled with glycerin, and the extracted hydrogen is measured after holding at 45℃ for 72 h. In

general, the gas chromatography is more popular.


・ Weld metals, Weld joints

・ Metallic materials

＜Measurable items＞

・ Amount of diffusible hydrogen in 100 g deposited metal (ml／100 g) or in weld metal (ppm)


・ Measurement of diffusible hydrogen content of deposited metals of carbon steels and special steels

・ Measurement of diffusible hydrogen content of steel springs and galvanized bolts

・ Measurement of hydrogen in welded joints of heat resistant steel by using an experimental hydrogen

sampling container


・ Measurement accuracy： 0.01 ml (Gas Chromatography)

0.05 ml (Glycerol Replacement Method)

[Hydrogen sampling container (front side)

and gas chromatograph] [Experimental hydrogen sampling container

for welded joint]

Diffusible hydrogen content of deposited metals of different types of welding consumables

Welding consumable Average

Low hydrogen covered electrode 7.1 7.0 7.2 6.9 7.1Solid wire 1.9 1.4 1.5 1.6 1.6

2.2 1.8 1.6 2.0 1.9

Diffusible hydrogen（ml/100g）

Submerged arc welding consumables

- 20 -

(5) Analysis by Fourier Transform Infrared Spectroscopy （ＦＴ-ＩＲ）

＜Outline＞

Substances consist of atoms and most of them form molecules. It is known that individual molecules

show their own vibration modes and frequencies. By measuring a frequency of a substance by using

infrared radiation, the molecular structure can be clarified. Besides, by comparing the molecular structure

with the measuring profile of a standard substance, the specimen can be identified or estimated. With its

microscopic function, a minute area of deposit can be analyzed.


・ Organic substances


・ Identification of substances

・ Identification of the features (functional group and state of binding) of the molecular structure of a

substance


・ Material identification of rubbers, plastics, adhesives, and lubricants

・ Material identification of coatings (oil and paint) on the surface of a machine part

・ Material identification of substances made by air and water pollution


・ Wave number：450-4000 cm－１

・ S/N ratio：4000/1（P-P） 20000/1（rms）

[Ethyl alcohol measured by FT-IR and function groups corresponding to peaks]

Tra

nsm

issi

vity

（%）

Wave number（cm-1）

Ethyl alcohol

- 21 -

(6) Tensile Test

＜Outline＞

In tensile testing, a specimen is pulled at a prescribed speed in one axial direction, and then the

elongation after fracture and the load necessary for the rupture are measured. The tensile test can clarify

the mechanical properties, such as proof strength, tensile strength and elongation of the specimen.



・ Plastics

＜Testing items＞

・ Proof strength, yield point, tensile strength, elongation, reduction of area, fracture position, and

fracture surface patterns


・ Tensile test of carbon steel weld metals and special steel weld metals

・ Tensile test of nonferrous weld metals (aluminum alloys and titanium alloys)

・ Tensile test of three-electrode ＦＣＢ welded joints (Room temperature)

・ Tensile test of Invar at low temperatures （-196 ℃）

・ Tensile test of heat-resistant steel weld metals at elevated temperatures （550 ℃）


・ Testing load： 20 kN～1000 kN, Testing temperature: from -196 ℃ to 1100 ℃

・ Testing specimen： As per the JIS standard

[Configuration of tensile specimen]

[Stress-strain curve]

Max. stress

Str

ess

（N

/m

m2)

Strain （%）

Gauge length: L

Gauge mark

Length of reduced section: P

Carbon steel

Aluminum

Rupture

Yielding

- 22 -

(7) Charpy Impact Test

＜Outline＞

In Charpy impact test, the ductility of a material "toughness" is measured by applying an impact to a

notched specimen by using a hammer to obtain absorbed impact energies. After impact testing, the

fracture surface of the specimen can consist of a glittering area and a lusterless area. The ratio of the

glittering area to the original cross sectional area of the specimen is referred to as the percent brittle

fracture. By plotting the percent brittle fracture of several specimens as a function of the testing

temperatures, a fracture appearance transition temperature can be obtained.



＜Testing items＞

・ Impact value（absorbed impact energy）

・ Percent brittle fracture and percent ductile fracture

・ Brittle-ductile transition temperature

・ Lateral expansion


・ Charpy impact test of carbon steel weld metals and special steel weld metals

・ Measurement of fracture appearance transition temperature of heat-resistant steel weld metals after

step-cooling heat treatment

・ Charpy impact test of low temperature service steels for offshore structures

・ Measurement of the lateral expansion of stainless steels


・ JIS- and ASTM-specified Charpy impact testing machines

・ Testing temperature： from -196 ℃ to +350 ℃

切欠き部

延性破面

脆性破面

〔試験片の破断面〕

Notch face

Ductile fracture

Brittle fracture

[Fracture surface of specimen]

[Transition curves of absorbed energy and percent brittle fracture]

×9.8

Percent brittle fracture

Absorbed energy

Absorbed energy transition temp.

Fracture appearance transition temp.

Testing temp. T

Per

cent

bri

ttle

fra

cture

(%)

Abso

rbed

ener

gy (

J)

- 23 -

(8) Creep Test

＜Outline＞

In creep test, a specimen is loaded with a constant tensile stress that is lower than its yield point (proof

stress) for long hours at a elevated temperature to measure the strain and rupture time of the specimen. It

is known that metallic materials are degraded in general when they are kept stressed at elevated

temperatures, because of changing their microstructures, coarsening carbides and generating vacancies

and cracks. Therefore, evaluating materials by creep test is indispensable for high temperature

applications.



＜Testing items＞

・ Strain-time curve (Creep curve)

・ Rupture time


・ Investigation of creep properties of heat-resistant steel weld metals for oil refinery reactors （550 ℃）

・ Investigation of creep properties of 11 %Cr steels for steam turbines （650 ℃）

・ Investigation of the relation of stress to rupture time after heat treatments (Annealing conditions)

・ Creep resistant test of Ni-based superalloy weld metals (750 ℃）


・ Single testing apparatus ― Max. testing load: 15 kN; Testing temperature range: 450-950 ℃

・ Multiple testing apparatus ― Max. testing load: 3 kN; Testing temperature range: 300-1000 ℃

▪ Testing specimen ― 6 mm dia. / 30 mm gauge length （12.7 mm dia. / 64 mm gauge length）

[Creep curve]

Elo

nga

tion （%)

Time after loading （h）

Room temp. Instant elongation

Min. creep rate

High temp.

Ruptu

re

Acc

el.

cree

p

Sta

tionar

y cr

eep

Tra

nsi

ent

cree

p

〔Creep rupture test results of 2.25 %Cr-1 %Mo steel weld metal〕

Test temp.

Creep rupture time

Str

ess

Mark SR condition

- 24 -

(9) Hardness Test

＜Outline＞

In hardness test, an indenter of diamond or metal is pressed onto the surface of a specimen and the

length of the diagonal line (or area) or the depth of the resultant dent is measured to calculate the

hardness. Hardness test is so popular and relatively simple, so that properties such as tensile strength,

crack susceptibility, wear resistance and cutting ability of materials and welds can easily be estimated from

the results. It is indispensable for testing and investigating materials because it is simple and informative.



・ Plastics

＜Testing Items＞・ Vickers hardness (HV), Rockwell hardness (HR) and Brinell hardness (HB)

＜Examples of applications＞・ Quality control test of steels for which hardness is specified by the JIS standard

・ Substitution for tensile test when the size and shape of a carbon steel specimen is not suitable for

tensile specimen

・ Evaluation of heat treatment conditions for steels

・ Judgment of welding procedure conditions by measuring hardness distributions in the base metal,

heat-affected zone and weld metal of a welded construction

・ Measurement of the depth of surface layer hardened by carburizing and nitriding

・ Measurement of the hardness of the vicinity of damaged area of a machine to detect any material

abnormality in investigation into damages of the machine


・ Vickers hardness tester : Testing force 0.09807-490.3 N

・ Rockwell hardness tester: Testing force As per the JIS standard

・ Brinell hardness tester : Testing force 4.903-3029.42 kN (Indenter: 10 mm)

[Hardness distribution of high tensile strength steel weld]

[Hardness distribution of nitrided layer

of surface treated part]

Distance （mm）

Vic

kers

har

dnes

s （H

V2)

Vic

kers

har

dnes

s （H

V0.0

5)

Distance from surface （mm）

Testing force

Surface

Base metalHAZ HAZ Base metal Weld metal

Testing force: 2kgf (19.61N)

Base metal : 0.5mm pitch

Weld metal : 1mm pitch

- 25 -

(10) Dry Sand / Rubber Wheel Abrasion Test

＜Outline＞

Dry Sand / Rubber Wheel Abrasion Test is to investigate the resistance of a material against the

scratching abrasion, one of abrasion phenomena, in which the surface of a material is gradually scratched

off by hard protrusions or granular solids. Specifically, silica sands are fed into the contacting surface

between a specimen and a rotating rubber ring, the mass of worn surface (abrasion loss) is measured, and

the surface condition is investigated. Easy-to-wear materials such as plastics result in a larger abrasion

loss, and wear resistant materials like tool steels result in a lower abrasion loss.



・ Ceramics

＜Testing items＞

・ Measurement of abrasion loss and investigation of the testing surfaces


・ Evaluation test of the hardfacing weld metals for crushers and mills

・ Evaluation test of the hardfacing treatment conditions

・ Wear resistance test of 18 %Cr cast irons

・ Wear resistance test of high Mn cast steels


・ Size of specimen：12.5 mm Thickness×25.0 mm Width×75.0 mm Length （Specimen thickness can be

from 3.2 to 15 mm）

[Abrasion loss of hardfacing weld metals vs. hardness]

Testing welding consumables:

produced by Kobe Steel

[Dry sand / rubber wheel abrasion test specimens

before and after test]

[Schematic of testing equipment]

Hardness (Hv)

Hopper

Silica sand

Lever arm

Nozzle for sand

Weight

Specimen

Rotating rubber ring Abra

sion loss

(g)

- 26 -

(11) High Temperature Friction Wear Test

＜Outline＞

The friction wear test is to investigate the degree of wear by rotating and rubbing two specimens

together (pin-on-disk type, or ring-on-disk type). The testing temperature can be from room temperature

to high temperatures. The worn mass (wear loss) can be obtained by measuring the mass difference of the

specimens before and after test and friction torque can be also obtained.



・ Ceramics

＜Testing items＞

・ Wear loss

・ Friction torque

・ Measurement of the actual temperature of the specimen (disk) during testing


・ Screening test of high-temperature wear-resistant materials for engine parts and brake parts

・ Wear resistance test of combinations of dissimilar property specimens for investigating relative wear

resistance and the suitability of combination

・ Wear resistance test of coated specimens for investigating the wear resistance of the coating

・ Investigation of the performance of the lubricating oil coated on a specimen

・ Wear resistance test of superhard materials


・ Testing temperature： Room temperature and 100-800 ℃

・ Specimen size ― Pin : Dia. of 5 mm×Length of 17 mm

Ring: Outer dia. of 25.5 mm×Inner dia. of 19.9 mm×Height of 18.0 mm

Disk: Square of 49.5 mm×Thickness of 10 mm

[Appearance of ring-disk type testing

specimens after testing]

[Types of friction wear test]

回転

試験力

リングオンディスク摩耗試験

回転

試験力

ピンオンディスク摩耗試験 Ring-on-disk wear test Pin-on-disk wear test

Testing force Testing force

Rotation

Rotation

- 27 -

(12) CTOD Test

＜Outline＞

The Crack Tip Opening Displacement (CTOD) Test is one of the evaluation tests of the fracture

toughness of constructions that contains defects. When a specimen with a crack is given a bending

external force at a particular temperature, the phenomenon "Instable Fracture" that the crack develops

rapidly, can occur. In the CTOD test, the crack tip opening displacement (CTOD value) is measured just

before the crack rapidly develops. Tougher materials have higher CTOD values. As to the standards for

the CTOD test, there are WES 1108, BS 7448 and ASTM E1290.


・ Welds (weld metal and heat-affected zone) of carbon steels and special steels（incl. low-alloy steels,

high tensile strength steels and low temperature service steels）

＜Testing items＞

・ CTOD values


・ Measurement of the CTOD value of low temperature service steel weld metals and high tensile

strength steel weld metals

・ Measurement of the CTOD value of 9 %Ni steels and its weld metal


・ 200-kN fatigue testing machine（for fatigue precrack）

・ 500-kN universal testing machine（for CTOD testing）

・ Testing temperature：－196 ℃ to room temp.

CTOD

Examples of specimen size：40t×80w, 80t×80w（mm）

Clip gauge

[CTOD test]

[CTOD transition curve of weld metal of covered

electrode for low-temperature steel]

CT

OD

va

lue

（m

m）

Temperature （℃） CTOD value

Covered

electrode

Thick.

(mm)

Heat.I.

- 28 -

(13) Drop-Weight Test

＜Outline＞

The drop-weight testing method is specified by the ASTM E208 standard. In this test, a specimen with a

crack starter bead is set onto the anvil of the tester in such a way that the notch of the crack starter bead

directs downward, and the weight is dropped freely onto th1

e specimen to apply an impact force to know whether or not the specimen breaks, and thereby the

brittle fracture characteristics of the specimen are investigated. While the Charpy impact test is to

examine whether a brittle crack generates or not and propagates easily or not, the drop-weight test is to

examine whether a brittle crack propagates easily or not and can be arrested or not because the crack

starter bead that contains a notch is a brittle weld metal.



＜Testing items＞

・ Whether the specimen breaks or not

・ NDT temperature (Nil-Ductility Transition Temperature of

materials)


・ Measurement of NDＴ temperature of steels for pressure vessels

used in cold regions

・ Measurement of NDT temperature of steels for nuclear reactor

pressure vessels

・ Measurement of NDT temperature of low temperature service

steel weld metals and heat-resistant low-alloy steel weld metals


・ ASTM-specified machine

・ Testing temperature：-196 ℃ to room temperature

[Drop-weight tester]

[Dimensions of specimen and crack starter bead 〕

[Measurement of NDT temperature of 3.5 %Ni steel weld metal （with covered electrode）]

： Broken to one edge

： Not broken

： Broken to both edges

Numeric： Crack length (mm)

th： Broken through Temp. for starting

test

Testing temp. NDT temp.（℃）

-85

Item

Thick.

Length

Width

Size Size SizeRange Range Range

Dimensions of specimen

Dimensions of specimen and crack starter bead

Weld bead Base metal

Notch

Welding direction

Weld bead

Base metal

1.5mm max.

- 29 -

(14) X-Ray Diffraction Test

＜Outline＞

When irradiating the characteristic X-ray of copper to a crystal material whose atoms are arranged

regularly, the reflection at an angle peculiar to the crystal structure (crystal face spacing) of the specimen

takes place. With an X-ray diffractometer, the crystal structure of the material, or the phase name, can be

identified by measuring the angle and intensity of the diffracted X-ray.


・ Crystal materials（Glassy substances cannot be measured）

＜Testing items＞

・ Identification of crystal structure or phase name

・ Measurement of the size of crystal lattice and strain of lattice

・ Measurement of residual stresses


・ Identification and analysis of raw mineral material

・ Identification and analysis of precipitates in metals (Investigation of carbide precipitates in steels by

means of extraction residue method）

・ Estimation of corrosive environment by means of identification and analysis of corrosion products


・ Max. power： 18 kW, Vertical goniometer

・ Micro part diffraction goniometer： Diameters of 10, 30, 50, and 100 μmφ

[Measurement of X-ray diffraction of raw rutile materials]

Rutile,syn-TiO２

Anatase,syn-TiO２

Inte

nsi

ty （C

PS）

Diffraction angle （2θ）

- 30 -

(15) Observation by Scanning Electron Microscope（ＳＥＭ）

＜Outline＞

A Scanning Electron Microscope (SEM) irradiates and scans a finely squeezed electron beam onto a

specimen to measure secondary electrons and reflected electrons and exhibits their intensities as images

on a monitor. As a result, the image of the specimen can be shown in a magnified size.



・ Ceramics, fibers (Vapor deposition treatment is needed）

＜Observation items＞

・ Surface observation at a magnification of 15-50,000 times

（Clear image can be obtained even if the testing surface is considerably uneven）

・ Analysis of elements（B-U） by Energy Dispersive X-ray Spectrometer（EDS）(accessory equipment)

（Rough composition of specimen can be known by semiquantitative analysis）

・ Identification of elements in micro areas（by qualitative analysis and semiquantitative analysis）


・ Investigation of the fracture mode and the causes of the fracture by observing the fracture surface of a

damaged mechanical structure

・ Analysis to confirm the kind and composition of metal by EDS analysis

・ Identification of elements in the specified area and micro portion during SEM observation


・ SEM ― Resolving power: 4 nm; Acceleration voltage: 0.2-30 kV; Magnification: 5-300,000 times

・ EDS ― Analyzable elements: B-U

〔炭素鋼の脆性破面〕〔炭素鋼の疲労破面〕〔炭素鋼の延性破面〕 [Semiquantitative analysis of SUS316 steel by EDS] (Mass %)

Note: Approximate values of intended elements

[EDX qualitative analysis of SUS316 steel]

Energy （keV）

Count

No.（

cps）

Analysis

* Composition specified by JIS G 4303

- 31 -

(16) Observation by Field Emission Scanning Electron Microscope

(with EDS/EBSD)

＜Outline＞

The Field Emission Electron Gun type Scanning Electron Microscope (FE-SEM) can irradiate and scan a

more finely squeezed electron beam than that of general SEM on a specimen, obtaining clearer magnified

images (of higher resolving power). Besides, with the Electron Back-Scatter Diffraction (EBSD), crystal

orientation and crystal structure can also be analyzed.



・ Ceramics

・ Fibers （Vapor deposition treatment is needed）


・ Observation of surface profiles at a magnification from 40-500,000 times

・ Observation of reflection electron image at a magnification from 40-100,000 times

・ Qualitative and semiquantitative analysis of elements（B-U）by Energy Dispersive X-ray Spectrometer

(EDS)。

・ Identification of elements in a micro portion （qualitative analysis and semiquantitative analysis）

・ Analysis of crystal orientation and crystal structure by EBSD


・ Observation of surface profiles of raw material of fine mineral powder（without vapor deposition）

・ Investigation of relationship between sensitization (precipitation of carbide) and crystal orientation of

stainless steel

・ Analysis of crystal orientation of solidified structure of weld metal

・ Confirmation of the crystal orientation of a one-way solidified alloy


・ FE-SEM ― Resolving power: 1.5 nm; Acceleration electron: 0.2-30 kV; Magnification: 15-500,000

times

・ EDS analyzer ： Analyzable elements; B-U

・ BESD analyzer: Crystal orientation; Min. analytical diameter≦0.2 μmφ

[Appearance of raw powder specimens

without vapor deposition]

[Example of EBSD analysis of cross sectional of

polycrystalline aluminum]

Crystal lattice

- 32 -

(17) Electron Probe Micro Analyzer (EPMA)

＜Outline＞

The Electron Probe Micro Analyzer (EPMA) irradiates a finely squeezed electron beam on a specimen

and detects characteristic X-rays generated from the irradiated area. Kinds of elements (Be-U) and their

distributions (0.01～100%) in the irradiated area (surface of the specimen) can be clarified.



・ Corrosion products and other foreign substances


・ Observation of surfaces at a magnification from 40-30,000 times

・ Identification of compositional elements in a micro portion（Analyzable elements: Be-U by qualitative

and semiquantitative analysis）

・ Line analysis

・ Area analysis and color-mapping analysis


・ Estimation of the particular operation environment by qualitative and semiquantitative analysis of

corrosion products attached on a construction

・ Investigation of element segregation by color-mapping analysis of steel ingot and weld

・ Investigation of the suitability of process conditions by line analysis and color-mapping analysis of

carburized and nitrided products

・ Analysis of the damaged area of a machine construction in investigation into damages

・ Qualitative and semiquantitative analysis of surface deposits on wires and rods


・ Analyzable elements: Be-U; Acceleration voltage： 0.2-40 kV; Magnification： 40-300,000 times

・ Size of specimen：100 mm Width×100 mm Length×50 mm Height

[WDS qualitative analysis of deposits]

[Color-mapping analysis and line analysis

of the tooth of a gear]

Group: SWS-2

Sample: Inclusions

Acceleration

voltage: 15.0kV

Irradiation current:

5.005E-0.8A

Scanning: ON

CH-1 TAP

CH-2 LDE2

CH-3 LDE1H

CH-4 LIF

CH-5 IETH

*ID Doctor*

A rank: C, O, Al, Si,

S, Ca, Ti, Mn, Fe,

Zr

Elements detected

- 33 -

(18) Electron Spectroscopy for Chemical Analysis (ESCA)

＜Outline＞

The Electron Spectroscopy for Chemical Analysis (ESCA) can determine what elements (Li-U) exist and

how they are bonded, by irradiating a soft X-ray on a specimen and by detecting the energy of

photoelectrons generated from the irradiated area. Since the photoelectrons detected by the ESCA

provide information of the depth from the irradiated surface to several nm, information of a subsurface can

be obtained, unlike EPMA. Besides, as the surface can be removed by argon ion spattering, the ESCA can

examine the concentration transition of an intended element in the depth direction through layer.



・ Ceramics and semiconductors


・ Identification of compositional elements（Li-U） by a Semi-Spherical Photoelectron Spectrometer

・ Chemical bonding state

・ Element distribution in the depth direction


・ Qualitative and semiquantitative analyses of deposits on the surfaces of circuit boards and circuits

・ Investigation into causes of discoloration of metal surfaces

・ Investigation of the chemical bonding of surfaces of stainless steels and aluminum alloys

・ Measurement of the thickness of the passive film of stainless steels and the oxide film of aluminum

alloys by means of depth direction analysis.


・ Analyzable elements: Li-U; Radius of Ｘ-ray beam： 9～100 μmφ

・ Max. sensitivity: 3,000,000 CPS when a half-value width of Ag 3d5/2 is 1.3 eV

Al-foil01.pro: MoS2, Al: Al-foil Company Name

2006 Mar 14 Al mono 24.9 W 100.0 μ 45.0° 112.00 eV 9.9750e+003 max 17.15 min

Al2p/Point3: Al-foil/1

6870727476788082848688 0

10

20

30

40

0

0.5

1

1.5

2

2.5

3

x 104

Binding Energy (eV)

c/s

Al2p

Surface

Inside

Spattering

frequency

（times）

[Depth direction analysis of pure aluminum surface]

Bonding energy (eV)

Spec

tral

in

tensi

ty （C

/S)

Al-foil01.pro: MoS2, Al: Al-foil Company Name

2006 Mar 14 Al mono 24.9 W 100.0 μ 45.0° 112.00 eV 2.4222e+004 max 9.81 min

Al2p/Point3: Al-foil/1

6870727476788082-0.5

0

0.5

1

1.5

2

2.5

3x 10

4 Al-foil01.pro (View Only)

Binding Energy (eV)

c/s

ＡｌＯＸ

Ａｌ-ｍｅｔａｌ

[Analysis of photoelectron spectrum on

pure aluminum surface]

Bonding energy (eV)

Spec

tral

in

tensi

ty （C

/S)

- 34 -

(19) Measurement of Transformation Temperature

＜Outline＞

Metallic materials, especially steels, change their crystal structures depending on heating temperatures,

resulting in their expansion or contraction. A change in the crystal structure of a substance at a

temperature is called phase transformation, and this temperature is named the transformation temperature.

The transformation temperature measuring equipment heats or cools a specimen at various rate in an inert

gas or in vacuum to measure the expansion or contraction of the specimen as a function of temperature.

Our equipment offers ① rapid heating and cooling and ② sub-zero treatment.



＜Measurable items＞

・ Measurement of thermal expansion

・ Analysis of transformation temperature

・ Measurement of linear expansion coefficient

・ Development of a Continuous Cooling Transformation Diagram（ＣＣＴ Diagram） and

Time Temperature Transformation Diagram （ＴＴＴ Diagram）


・ Analysis of transformation temperatures of steels, wire rods and weld metals

・ Development of CCT and TTT diagrams of heat-resistant steel weld metals

・ Heat treatment simulation for steels and wire rods（incl. sub-zero treatment）

・ Simulated weld thermal cycle test of carbon steels


・ Heating method： Ultrahigh temperature infrared image heating

・ Heating and cooling capacity： Max. heating temp.: 1450 ℃; Controlled heating: 100 ℃/s or higher;

Controlled cooling: 70 ℃/s or higher.

・ Sub-zero treatment： down to -150 ℃

・ Size of specimen： 3 mmφ×10 mm Length

・ Accessory equipment： Water quenching（ＷＱ）equipment

Ms

Mf

Ac1

Ac3

Ms

Mf

Ac1

Ac3

Heating

Cooling Elo

nga

tion （μ

m）


Elongation

Tem

per

ature

（℃

）

Time （ｓ）

Elo

nga

tion （μ

m）

[Analysis of transformation temperatures

of heat-resistant steel weld metal]

Temperature

[Sub-zero treatment after

heat treatment simulation for steels]

- 35 -

(20) Observation of Macrostructure and Microstructure

＜Outline＞

The metallic structure tests can be classified into macrostructure test by naked eyes or with a

magnifying glass of low magnification (magnification: approx. 20 times max.) and microstructure test for

observing so fine structure that naked eyes cannot discriminate (magnification: approx. 1,000 max.). The

macrostructure test is to examine the metallurgical and geometrical uniformity of a relatively wide area of

and defects in a specimen, and the microstructure test is to examine a limited area of specimen at a high

magnification. According to welding terms of the JIS standard, macrostructure test is defined to investigate

the penetration, heat-affected zone and defects in the weld surface or cross section by naked eyes after

processing the specimen by polishing or etching with a etchant. On the other hand, microstructure test is

defined to examine metallic structures by using a microscope after etching the cross section of a weld

specimen with a etchant.




・ Observation of macroscopic structure

・ Observation of microscopic structure


・ Measurement of weld leg length and observation of penetration characteristics to judge the welding

procedure.

・ Observation of inclusions and segregation in metallic materials

・ Investigation of the presence of notches and defects in the cross section of the damaged portion of a

mechanical structure

・ Investigation of the cross section of a corroded portion in terms of corrosion depth and mode

・ Observation of the thickness of plating and the depth of carburized or decarburized layer

・ Observation and measurement of crystal grain size

・ Judgment of heat treated condition of carbon steels and low-alloy steels

・ Investigation of thermal environments by observing carbide precipitates along grain boundaries of

stainless steels


・ Digital projector ： Magnification of 2 , 5, 10 and 20 times

・ Digital microscope： Magnification of 12.5-1,000 times

[Macrostructure of butt welded joint] [Microstructure of stress corrosion cracking

of SUS316 steel]

50μm

- 36 -

(21) Observation by Transmission Electron Microscope (TEM)

＜Outline＞

The Transmission Electron Microscope obtains transmission electron images and electron beam

diffraction images by irradiating electron beams with high acceleration voltages on a specimen and by

magnifying the electron beams transmitting the specimen with an electromagnetic lens. With the

transmission electron images, grain boundaries, defects, strains and precipitates can be observed, while

the electron beam diffraction images make it possible to identify crystalline substances and to analyze

crystal orientations.




・ Observation at a magnification of 1,000-1,000,0000 times

・ Identification of elements in a micro portion by EDS analysis（qualitative and semiquantitative analysis

of elements: C-U）

・ Identification of crystalline substances and analysis of crystal orientation


・ Morphological observation, quantitative analysis and identification analysis of precipitates in steels

・ Observation of sensitization and analysis of grain boundary segregation in stainless steels

・ Measurement of distributions of elements in finely solidified structure

・ Quantitative analysis and identification analysis of nonmetallic inclusions in weld metals

・ Morphological observation, quantitative analysis and identification analysis of welding fumes

・ Observation of the behavior of fine precipitates in various metals


・ TEM ― Resolving power: 0.14 nm (Lattice image); Acceleration voltage: 300 kV; Magnification:

1000-1,000,000 times

・ EDS analyzer ― Analyzable elements: C-U

0.5 μm

Magnified

[Observation of welding fumes]

EDS analysis location

[Results of WDS qualitative analysis of welding fumes]

Count

（cp

s）

Energy （keV）

Detected elements：O, Cr, Mn, and Fe

- 37 -

(22) Thermal Analysis

＜Outline＞

Thermal analysis is a series of techniques of measuring the physical properties of a substance or its

reaction product as a function of temperature or time by changing the temperature of the substance

according to a controlled program.


・ Metals

・ Glasses and minerals


・ Thermo Gravimetric Measurement （TG）： Measurement of mass change of a specimen associated with

temperature change

・ Differential Thermal Analysis (DTA)： Measurement of the temperature difference between a specimen

and the primary standard associated with temperature change

・ Differential Scanning Calorimetry (DSC)： Measurement of caloric comings and goings from a sample

associated with temperature change

・ Thermo Mechanical Analysis (TMA)： Measurement of length change of a specimen associated with

temperature change under a constant compression or tensile load


・ Measurement of temperatures of decomposition, dehydration and transformation of minerals (TG-DTA)

・ Measurement of transformation temperature and melting point of metals (TG-DTA)

・ Measurement of dehydration and property alteration of welding fluxes (TG-DTA)

・ Measurement of thermal expansion coefficient of macromolecules and metals (TMA)

・ Measurement of the glass transition point and softening point of macromolecules


・ Thermo Gravimetric Measurement： Measuring temperature range; room temp. to 1700 ℃

・ Differential Thermal Analysis ： Measuring temperature range; room temp. to 1700 ℃

・ Differential Scanning Calorimetry ： Measuring temperature range; room temp. to 600 ℃

・ Thermo Mechanical Analysis ： Measuring temperature range; -150℃ to 1500 ℃

[TMA measurement of Al-Cu alloy〕

[DTA and TG measurements of industrial pure iron]

DTA

(μV)TG (%)

Temp.

(℃)

Time (min)

TM

A (μ

m)

Temp (℃)

Heating rate: 10 ℃/min

Atm. gas: Ar 200 ml/min

Load: 5 g

- 38 -

(23) Measurement of Surface Roughness

＜Outline＞

There are two types of the measuring equipment for measuring surface roughness: the contact type and

the non-contact type. The contact type uses a contact shoe kept in contact with the surface of a

specimen, while the non-contact type uses an electron probe (scanning electron microscope) or a laser

(confocal laser microscope) to measure fine ridges and valleys on the specimen surface, observing a high

magnification images.



・ Ceramics and plastics

＜Measuring items＞

Contact type

・Each arithmetic average value of arithmetic mean roughness（Ra）, maximum height（Ry）, mean

roughness of 10-point measurements（Rz）, mean spacing of ridges and valleys（Sm）, mean spacing of

local ridges（S） and load length ratio（tp）

Non-contact type

・ Measurement of the difference between ridges and valleys（Measurement in a unit of μm）

・ Three dimensional display


・ Evaluation of the performance of dies by measuring the surface roughness of the drawn wire

・ Investigation of the machining accuracy by measuring the shape of the machining traces

・ Measurement of the shape of weld bead

・ Measurement of the surface roughness of a wire

・ Measurement of the surface roughness of a titanium plate

・ Measurement of the shape of the screw of a bolt

・ Measurement of the roughness of an aluminum plate


・ Resolving power ― Contact type : 0.02 μm

Non-contact type: 0.01 μm （Laser microscope）

0.005 μm（FE-SEM）

[Measurement of the wire surface by using

a contact-type roughness meter]

Distance （μm）

Dep

th o

f va

lleys

and h

eigh

t

of ri

dge

s（μ

m）

[Measurement of surface of \500 coin by using a non-contact roughness meter]

D

epth

of

valle

ys an

d

hei

ght

of

ridge

s （μ

m）

Distance （μm）

Marking of sample: 195405 Curve = R - position = [1]

Results of parameter: Curve = R - position = [1] Name of parameter: Result Name of parameter: Result Ra 0.429μm Ry 4.313μm Rz 3.673μm Sm [10.000%] 214.402μm S 135.715μm mr [10.000%P] 0.627%

- 39 -

(24) Image Analysis

＜Outline＞

In the image analysis, digital images are taken by a CCD camera and are processed by computer to

measure the number, area and length of particles.


・ Photographs

・ Objects


・ Measuring of areas

・ Measuring of lengths

・ Measuring of numbers


・ Measurement of graphite spheroidizing ratio and pearlite ratio of nodular graphite cast iron

・ Measurement of nonmetallic inclusions

・ Measurement of ferrite grain size of steels

・ Measurement of austenite grain size of steels

・ Measurement of cross-sectional shape of wires（e.g. diameter and cross-sectional area）

・ Measurement of grain shape and dimension of powders


・ Multipurpose image processing

・ Color extraction function

・ Shooting correction function

・ Color detection function

・ Transparent display of detected images

・ Automatic correcting function of concentration levels

[Image processing view for measurement

of grain sizes by ASTM method] [Image processing view for measurement

of graphite spheroidizing]

- 40 -

(25) Nondestructive Test

＜Outline＞

The nondestructive test is to inspect materials, equipment, welded constructions to detect the surface

flaws, internal defects, welding defects, and other damages without cutting and decomposing the testing

objects. There are several methods; visual test, radiographic test, ultrasonic test, magnetic particle test

and dye penetrant test.


・ Materials, equipment and welded constructions

＜Testing items＞

・ Visual Test: Investigation of the surface flaw, shape, dimension and color tone by visual observation or

with a magnifying glass

・ Radiographic Test: Investigation of the internal defects and conditions (applicable for thicknesses up

to 70 mm, usually up to 50 mm, for carbon steels)

・ Ultrasonic Test: Investigation of internal defects and their positions from the surface

・ Magnetic Particle Test: Investigation of open defects on the surface and internal defects in the

subsurface

・ Dye Penetrant Test: Investigation of open defects on the surface


・ Investigation of weld cracks in welded constructions

・ Investigation of slag inclusions and blowholes in welds

・ Confirmation of a location of leakage in pipings

・ Measurement of reduction in the thickness of pipings

・ Confirmation of penetration of aluminum welds

・ Investigation of shrinkage cavities in castings

・ Confirmation of the interior of an electronic part

[Dye penetrant test of a pipe] [Ultrasonic test of a pipe] [Magnetic particle test of a pipe]

[Radiographic test of a remote controller]

- 41 -

(26) ｙ-Groove Weld Cracking Test

＜Outline＞

The y-Groove Weld Cracking Test is to investigate cold cracking susceptibility of welds. In this test,

the root pass bead is weld in y-groove joint in which stress concentration is highest among butt welded

joints. After welding was finished, the test assembly is left in the air for a sufficient time so that diffusible

hydrogen in the weld can diffuse sufficiently (48 h for carbon steels). And then the weld is checked for

cracking. The JIS standard Z 3158 (y-Groove Wed Cracking Test) specifies to measure the surface crack

ratio, root crack ratio and sectional crack ratio. With this test, the minimum preheat temperature to

prevent cold cracking can be obtained by changing the preheat temperature for the base metal and the

conditions of welding environment (by using the controlling room for temperature and humidity).


・ Welds (weld metal and heat-affected zone) of carbon steels and special steels（incl. low-ally steels,

high tensile strength steels, and low temperature service steels）

＜Testing items＞

・ Cold crack susceptibility of weld

＜Examples of applicatons＞

・ Investigation of cold crack susceptibility of HT490 class steel welds

・ Investigation of cold crack susceptibility of HT780 class steel welds

・ Investigation of cold crack susceptibility of heat-resistant steel welds

・ Investigation of cold crack susceptibility of 1.5 % Ni low temperature service steel welds

[Cracking test results of HT780 class steel weld by shielded metal arc welding]

[Shape and size of ｙ-groove weld cracking test plate]

Single bead

Testing groove

200

A

A'

B

B'

Restraint weld

60

t/2

g

60゜

B-B'

150

A-A'

Root

crac

k ra

tio

(%)

Temperature of steel plate before welding（℃）

t/2

6080

Testing plate: HT780 (Ceq = 0.49), 32 mm

Welding Atm.: 25℃×80%RH (19.0 mmHg)

After 400℃×1Hr drying

After 30℃×80%RH×30Min exposure in the air

- 42 -

(27) Varestraint Cracking Test

＜Outline＞

Varestraint Cracking Test (variable restraint test) is to examine the high temperature crack

susceptibility of a weld. In this test, automatic TIG welding is carried out on a testing plate, during which

an instantaneous bending load is applied to deform the testing plate, thereby causing hot cracks in the

molten bead. This test can evaluate the susceptibility of a weld against solidification crack and reheat

liquation crack, separately. This test is utilized for comparing the crack resistance of welding consumables

and for screening the welding conditions, which can evaluate crack susceptibility quantitatively by

changing the bending radius of the jig (or the amount of strain) and by measuring the temperature range

where crack occurs in the specimen.


・ Welds (weld metal and heat-affected zone) of carbon steel and special steel (e.g. low-alloy steels and

stainless steels)

・ Welds of nonferrous metals (e.g. nickel alloy)

＜Testing items＞

・ Hot crack susceptibility of welds


・ Investigation of hot crack susceptibility of weld metal of

austenitic stainless steels


nickel alloys


carbon steels

[Solidification cracking brittleness of carbon steel weld metal by submerged arc welding]

Jig

[Outline of varestraint cracking test]

[Varestraint crack testing equipment]

Base metal: SS 400, 9 mm thick. Weld metal: US-43 (4.8 mmφ)/G-80, 450 A-20 V-200 mm/min

Specimen size and welding orientation and applied force

Spot varestraint

Trans varestraint

Varestraint

Crack

Applied force direction (from front side to back side of this paper)

Radius of jig

Plate thickness:

T

Specimen

Auxiliary plate

Applied force TIG welding


Test welding conditions

Ordinary weld metal

Temperature range of solidification brittleness

Str

ain a

dded

(%)

- 43 -

(28) Measurement of Welding Fumes

＜Outline＞

Welding fumes are a kind of dust, which consist of fine particle metal oxides that were formed by

combining metals vaporized in welding arc with oxygen during cooling. The emission rate of fumes can be

measured in accordance with the JIS standard Z 3930 (Determination of emission rate of particular fume in

arc welding) by using a high volume air sampler (1.5 m3/min). In this method, a covered electrode or

welding wire is kept in fixed position in a fume collecting box with an inner volume of 0.32 m3, and

bead-on-plate welding is carried out in the flat position. And then all the fumes generated are collected on

a filter paper (made of glass fibers), and the emission rate of fumes per welding time or per amount of

welding consumables used is measured. Besides, the chemical analysis of welding fumes collected on the

filter paper according to the above-mentioned method can also be made according to the method specified

by the JIS Z 3920 (Methods for chemical analysis of elements in welding fumes).


・ Welding consumables


・ Measurement of emission rate of fumes per welding time (mg/min)

・ Measurement of emission rate of fumes per amount of welding consumables used (mg/g)

・ Chemical analysis of each component in welding fumes


・ Measurement of emission rate of fumes of MAG and MIG welding wires

・ Measurement of emission rate of fumes of covered electrodes

・ Measurement of emission rate of fumes of TIG welding wires

・ Investigation of relationship between shielding gas composition and emission rate of fumes in MAG

welding

・ Analysis of fumes of various welding consumables (e.g. Fe2O3, SiO2, MnO, TiO2, Al2O3, Na2O, K2O, F,

NiO, Cr2O3, CuO, PbO, and ZnO)

[Fume collector for arc welding]

[Fume emission rates of low-fume type electrodes]

Fume emission rate (mg/min.)

Low-fume type Ilmenite electrode

Low-fume type lime titania electrode

Low-fume type high titaniam oxide electrode

Low-fume type low hydrogen electrode

Low-fume type vertical down electrode

Low-fume type vertical down electrode

Ordinary Ilmenite electrode

Ordinary lime titania electrode

Ordinary high titaniam oxide electrode

Ordinary low hydrogen electrode

Ordinary vertical down electrode

Ordinary vertical down electrode

Size

Size

Size

- 44 -

(29) Measurement of Welding Spatters

＜Outline＞

Welding spatters consist of fine particles of molten metals scattering from the tip of a covered electrode

or a welding wire and a molten pool. Since no standard specifies the measurement of the amount of welding

spatter, various measuring methods are used. In general, the emission rate of spatters is measured in such

a way that all spatters generated from the arc are collected in spatter collectors. Specifically,

bead-on-plate welding is carried out in the flat position, all spatters generated are collected with

collectors made of copper equipped around the arc, weigh the amount of spatters collected and the

emission rate of spatters is calculated per unit time or per amount of welding consumables used.

Furthermore, the distribution of particle sizes of welding spatters, collected by the above-mentioned

method, can be measured.

＜Applicable specimens and equipment＞

・ Welding consumables

・ Welding power sources


・ Emission rate of welding spatters per unit time (mg/min)

・ Emission rate of welding spatters per welding consumables used (mg/g)

・ Particle size distribution of welding spatters

＜Examples of applications ＞

・ Measurement of emission rate of welding spatters with MAG and MIG welding wires

・ Measurement of emission rate of welding spatters with covered electrodes

・ Measurement of emission rate of welding spatters with particular MAG and MIG welding power sources

・ Investigation of relationship between shielding gas composition and emission rate of welding spatters

by MAG welding

・ Investigation of relationship between the surface condition of steel plates (with or without anti-spatter

agents) and emission rate of welding spatters by MAG welding

[Welding spatter collectors]

〔スパッタ発生量に及ぼす溶接電流の影響調査〕

Spatter

Welding

torch

Spatter

collecting box

Testing plate

Size of testing plate：25t×60w×450ℓ （mm）

60w

450ℓ 25t

Wire dia.：1.2 mmφShielding gas: Ar+20%CO2

Em

issi

on r

ate

of sp

atte

rs (

mg/

min

.)

[Effect of welding current on emission rate of spatters]

Welding current (A)

YGW16 conventional wire andconstant voltage power source

SEA-50 wire andconstant voltage power source

SEA-50 wire andpulsed current power source

- 45 -

(30) Measurement of Welding Strain and Residual Stress

＜Outline＞

We contract for measuring dynamic strain and residual stresses. In measuring dynamic strain, a gauge

and a sensor are attached on a specimen and then welding or testing is conducted to measure strain

changed with a passage of time. For the measuring equipment, a digital logger is used. In measuring

residual stresses, a strain gauge is attached on the measuring location of a specimen. And then, by

measuring the difference between the strain when the gauge is attached and that when the specimen is cut,

the residual stress is calculated by using the material characteristics of Young’s modulus and Poisson’s

ratio.


・ Welded joints

・ Test pieces for mechanical testing

・ All sorts of metallic materials and components


・ Welding strain

・ Residual stress


・ Measurement of dynamic strain during welding of aluminum alloy joints

・ Measurement of residual stress of welded joint of carbon steel pipes

・ Measurement of residual stress of FSW joint of aluminum alloys

・ Measurement of dynamic strain of tension test specimens

・ Measurement of residual stress of bent pipe of stainless steels


・ Data Logger made by National Instruments SCXI1121+LabVIEW (for dynamic strain)

・ Data Logger made by Kyowa Electronic Instrument UCAM-65A (for residual stress and static strain)

[Example of strain gauge attached]

[Investigation results of residual stress vs. distance from bead (MAG welding of carbon steel)

Ｄｉｓｔａｎｃｅｆｒｏｍｂｅａｄ（mm）

Res

idual

str

ess

(MPa)

Bead

Longitudinal to bead

Transverse to bead

- 46 -

(31) Example-1 of Damage Investigations

（Fatigue Fracture）

＜Contents＞

■ The macroscopic and microscopic observations of the fracture surface mode are the most effective

means for the investigation into causes of damages when the fracture surface is preserved in the case of

damages of structures and machine parts. Especially, the microscopic observation of the fracture

surface by SEM can provide a definite evidence to identify any fracture mode and initiation site.

■ Mentioned below is an example of investigation of a fatigue-fractured bolt that had been used for a

building structure. As shown below in a schematic view of the appearance of the bolt, it was obvious

that the bolt was broken along a screw groove. And as shown below in a schematic macroscopic view of

the fracture surface, it was conspicuous that the bolt was loaded by repetitive forth-and-back

directional stresses. Furthermore, the magnified microscopic observation revealed that fatigue fracture

occurred in the bolt because a striation pattern was observed in the fractured surface, as shown in the

SEM fractograph below.

■ It was concluded that the bolt was broken by a fatigue crack initiated and propagated by repetitive

forth-and-back stresses at the bottom of a screw groove where stress was likely to concentrates due to

its specific structure and configuration. Based on this result, some preventive measures can be

proposed as follows: ① Modify the design of the main structure so as to minimize its vibration. ②

Change the material of the bolt to be higher in strength. ③ Fasten the bolt uniformly and firmly.

＜Investigated specimen＞

・ Building structure

・ Bolt（Material： Carbon steel）

Striation pattern

Evidence of fatigue fracture

[Microscopic fractograph by SEM]

[Schematic of appearance of bolt]

：破断位置

A

B

ねじ溝底部で破断Fractured at the bottom of a screw

Location of fracture

Macroscopic fractography (Schematic directions of

crack propagation）

Crack initiation

Beach mark

：Direction of crack propagation

Crack initiation

Beach mark

- 47 -


（Stress Corrosion Cracking）

＜Contents＞

■ In addition to microscopic fractography, observation of the pattern of a crack in the cross section can

provide effective evidences to identify the fracture mode, initiation and path. In case where deposits

like corrosion products remain in the fracture surface, microanalysis of the deposits is very useful to

estimate the corrosive environment.

■ Discussed below is an example of investigation of a pipe that was damaged by stress-corrosion cracking.

As shown in the schematic below, cracks occurred at the vicinity of the weld. Fractography of the

cracks revealed that the fracture surface exhibited intergranular and quasicleavage fracture patterns of

corrosion cracking. In observation of the cross section of the cracks, it was found that the cracks

branched as recognized typically for an ordinary stress corrosion crack and the crack propagated from

the outside to the inside. In WDS analysis of deposits on the pipe, chlorine (Cl) was detected.

■ This investigation revealed that the cracks initiated and propagated as stress corrosion cracks because

the elbow pipe-to-straight pipe weld was exposed under residual stresses to a Cl-bearing corrosive

environment. To prevent this problem, it is recommended to use better corrosion resistant steels over

SUS304 steel.


・ Chemical plant equipment

・ Piping weld（Material：SUS304）

[SEM microscopic fractography]

Mixture of intergranular and quasicleavage fracture patterns

Cross sectional microstructure〕

Crack branches

Typical stress corrosion cracks

[WDS qualitative analysis results of deposits]

Cl-bearing environment

[Schematic view of pipe weld]

: Cracks

Weld

Cl Cl

- 48 -


（Hot Crack）

＜Contents＞

■ Discussed below is an example of application of SEM fractography and cross sectional observation of a

weld crack. In this investigation, cross sectional color-mapping analysis by EPMA was revealed to be

effective for identifying causes of the crack initiation.

■ Investigated was an electric part (blade) that generated a hot crack. A crack generated in the weld of

the blade shown in the schematic blade below was revealed to have a solidification fracture surface by

fractography. In observation of the cross section of the weld, the crack was located in the vicinity of

the middle part of the weld. Furthermore, in color-mapping analysis of the cross sectional cracked area

in terms of sulfur, the segregation of sulfur was found in the vicinity of the crack.

■ This investigation revealed that the electric part was made of the base metal containing much sulfur,

and thus sulfur concentrated at the final solidification portion, thereby causing the hot crack

(solidification crack). Therefore, it is recommended to use the base metal containing less sulfur as a

preventive measure.


・ The blade of an electric part

（Material: Carbon steel（with a high S content）

・ Weld（Material： Carbon steel weld）

[SEM fractography]

Solidification fracture surface

Hot crack

[Color-mapping EPMA analysis of sulfur]

Sulfur segregation in vicinity of crack

[Cross sectional macrostructure〕

A crack occurred at the central part of the weld

：亀裂

[Schematic view of blade]

Weld

Crack

- 49 -

αphase γphase γphase

Analysis location ②

Analysis location ①

(34) Example-1 of Material Evaluations

（TEM Micrography of Structures)

＜Contents＞

■ It is known that such various properties of materials as strength, toughness, corrosion resistance

depend largely on their microscopic structures. Especially, since most of metallic materials are

polycrystalline substances consisting of fine crystals, TEM which uses thin films and extraction replicas

is an effective means to examine the characteristics of materials by structure observation, element

analysis, and identification of precipitates by using electron beam diffraction patterns.

［Example of observation of a duplex stainless steel weld metal（1）］

As-welded： Element analysis of base phase（α,γ）

Shown here are examples of analyses of elements

distributed into two phases of an as-welded duplex

stainless steel weld metal. The ferritic phase contains

larger amounts of Cr and Mo but smaller amounts of Fe

and Ni as compared with the austenitic phase.

[Results of EDS semiquantitative analysis] （％）

［Example of observation of a duplex stainless steel weld metal（2）］

Shown here is an example of investigation of

the structural change when the same weld metal

as that mentioned above was heat treated for 500

℃ aging. It was revealed, by EDS analysis and

electron beam diffraction, that the heat treatment

produced needle-shaped and plate-shaped σ

phases with high amounts of Cr, Mo, and Si.

[Results of EDS semiquantitative analysis] （％）

Specimen Analysis

locationＳｉＭｎＦｅＮｉＣｒＭｏ Remarks

① 1.7 0.5 63.2 9.2 23.2 2.3 Austenite (γ) As-welded

② 2.4 1.3 57.9 5.0 28.8 4.6 Ferrite (α)

Specimen Analysis

location ＳｉＭｎＦｅＮｉＣｒＭｏ Remarks

Aged at 500℃ ③ 3.6 0.4 49.0 6.6 28.0 12.5 Sigma (σ) phase

αphase

Note: Rough index for intended elements

（Analysis

location ③）

Precipitate

γphase

500℃ aging heat treatment： Identification of precipitates

Electron beam diffraction pattern

σ phase （FeCrMo）

1μm

1μm

Note: Rough index for intended elements

- 50 -

(35) Example-2 of Material Evaluations

(Analysis of Crystal Orientation by EBSD)

＜Contents＞

It is known that the properties of polycrystalline materials depend on the distribution of and relationship

between crystal orientations. Conventionally, they have been investigated by using pole figures by means

of X-ray Diffractometry. In recent years, the SEM/EBSD method has become more popular, by which

individual crystal orientations can be measured, and the relationship between a particular crystal

orientation and the neighboring crystal orientation, as well as intergranular structures, can individually be

investigated. The EBSD is a method for observing microstructures in the light of the difference in crystal

orientation and crystal structure by analyzing the backscatter Kikuchi diffraction obtained by electron

beam irradiation. (Note: EBSD stands for Electron Back-Scatter Diffraction)

［Example of EBSD analysis of top surface of stainless steel

weld metal (1）］

This is an example of EBSD

analysis of a 1-mm width of the

machined and polished top surface

of a stainless steel weld metal. It is

clear that the crystal plane of

(110), a preferred solidification

orientation of individual columnar

crystals, faces approximately the

welding direction.

［Example of EBSD analysis of cross section of stainless steel

weld metal （2）］

This is an example of EBSD

analysis at high magnification of

the same stainless steel weld

metal as that mentioned above.

It is clear that γ austenite

precipitates from δ ferrite in the

surroundings (blue or sky blue

areas) and their crystal

orientations are in the relation of

〈111〉γ//〈110〉α.

backscatter Kikuchi

diffraction

電子線回折パターン

＜Pole figure＞＜Crystal lat

Color Key

Crystal lattice

Welding direction

- 51 -

(36) Example-1 of Researches for Welding and Joining

(Scrum Rivet MIG welding of Steel and Aluminum)

＜Contents＞ ■ In order to use much more aluminum alloys to fabricate automobiles, it is necessary to establish a

more reliable joining technique for dissimilar metals of steel and aluminum alloy. With conventional

MIG welding, sufficient joint strength cannot be obtained because brittle Fe-Al intermetallic

compounds are produced in the joining interface. To overcome this problem, The Scrum Rivet MIG

Welding Process has been developed. With this process, MIG welding of a steel-aluminum lap joint

can be conducted with an aluminum alloy wire on the aluminum alloy bottom plate through the holes

made in the top steel plate.

■ The Scrum Rivet MIG Welding Process has advantages over conventional welding processes for

welding dissimilar metal joints: ① Simple equipment based on the conventional MIG welding

process; ② Intermetallic compounds of the Fe-Al system can be disregarded; ③ The joint

strength ratio can ensure 70%.

■ This research was given in trust to the New Energy and Industrial Technology Development

Organization (NEDO) from the Ministry of Economy, Trade and Industry in the fiscal year of 2004,

as “Technical Development for Innovative Countermeasures against Global Warming through

Rationalizing Energy Uses ― Development Project of Advanced Processing and Forming

Technologies of Aluminum Alloys for Automobile Weight Reduction.” The development of the new

welding process was conducted as one of our collaborative researches with the Kobe Corporate

Research Laboratories of Kobe Steel, Ltd.

[Cross sectional macrostructure] [Tensile strength]

Joint efficiency: 70％ to base metal rupture strength

0

10002000

30004000

5000

60007000

80009000

10000

1 2 3 4 5

Alワイヤ種類

破断

力（N）

50cpm

70cpm

90cpm

4043 4047 5554 5356 51830

10002000

30004000

5000

60007000

80009000

10000

1 2 3 4 5

Alワイヤ種類

破断

力（N）

50cpm

70cpm

90cpm

4043 4047 5554 5356 5183

Strength per 30-mm width

Welding speed

[Comparison with dissimilar-metal joining processes]

鋼板鋼板

Joint geometry is similar to that in rivet joining

Steel plate

Aluminum wire

Aluminum alloy plate

Through-thickness hole

[Scrum Rivet ＭＩＧ Welding Process]

○○ ×Weight

reduction

PlateJoint type

△○ ×Workability

Solid phase joining

○○ ×

△○ ×

Scrum rivet joining

Rivet joining

Circular column and other types

Plate

Sufficient strength can be obtained with the

penetration into the bottom plate of aluminum alloy

by making holes in the top steel plate, through which

MIG welding is performed with an aluminum wire.

Aluminum weld metal

Types of aluminum wires

Ruptu

re s

tren

N)

- 52 -

(37) Example-2 of Researches on Welding and Joining

(Laser Welding Technology for Iron Powder Sinterd Parts)

＜Contents＞ ■ Iron powder metal parts for automobiles cannot necessarily be produced in single piece due to the

production restriction in product shape. Complicated shape parts, therefore, have been examined to

produce by joining simpler sintered parts. Popular, conventional welding processes, however, are

technically difficult to apply for iron metal powder parts because of the occurrence of welding

defects; hence, there was no established technique until recent year. In view of this situation, an

advanced laser welding process with a special filler wire has been developed in order to obtain sound

welds efficiently for iron powder metal parts.

■ The conventional laser welding causes weld cracks and blowholes in high carbon iron powder metal

parts. The advanced laser welding process offers deep penetration, less distortion, and high

efficiency, by using a special filler wire (high Mn-Al-Ti type) that contains deoxidizing elements

such as aluminum, titanium, and manganese for preventing blowholes and an austenite-forming

element of nickel for preventing weld cracks, and by optimizing the welding conditions. It has also

been confirmed that the postweld heat treatment is effective for improving the tensile strength.

[Conventional laser welding]

[Cross sectional macrostructure] [Tensile strength]

Kind of defect Blowhole Cold crack Hot crack

Cause of

occurrence

Many pores C content：

High

Segregation of

low melting

point compound

in grain

boundaries

Concept for

prevention

Addition of

deoxidizer

Austenitizing of

weld metal

Fixation of S

Measures Addition of Al,

Ti, Mn

Addition of Ni Addition of Mn

Success in preventing welding defects

Without

filler wire

With

filler wire

Welding wire

Postweld heat treatment secures tensile strength

comparable to base metal （fractured at base metal）

[Concept for developing suitable wires]

Flux (High Mn-Al-Ti type)

Sheath metal (Cr-Ni type)

Occurrence of cracks and blowholes

Base metal

- 53 -

(38) Example-3 of Researches on Welding and Joining

(Technology for Direct Lining of Titanium on Steel Plate)

＜Contents＞ ■ Titanium has been used for chemical plants and power plants due to its excellent corrosion

resistance. Lately, it has been tried to apply titanium for offshore structures ― e.g. the titanium

lining for preventing corrosion of bridge piers and very large floating structures (Mega-Float) in the

sea. For these purposes, costly titanium clad steel has been used because titanium-steel directly

welding is difficult. In response to this issue, an advanced MIG brazing process has been developed

as the lining technique by using a small diameter copper alloy wire for direct welding of a titanium

plate (approximately 1mm in thickness) on a steel plate.

■ This new MIG brazing process uses a welding wire of Cu-3%Si-1%Mn alloy with a diameter of 0.8mm

and optimized welding conditions (welding current and wire feeding location) to minimize the

generation of brittle Ti-Cu intermetallic compounds for preventing weld cracks. This process

provides a joint strength of 300MPa or higher, which is sufficient for practical applications.

Steel plate

Weld metal Titanium

plate

[Lining test assembly]

Ensure 300 MPa or higher tensile strength

[Tensile strength]

Welding conditions

Ten

sile

st

rengt

h （M

Pa）

Titanium

plate

Welding torch

[Welding process]

Presser plate

Steel plate

Minimize intermetallic compounds (Area ① in Photo)

〔Joint interface〕

Cu

Copper Titanium

Cu ①

①

- 56 -

（Tech.-001 Rev.2.0.2.1E ： 2007/3/1）

For the permission of reproduction, translation and duplication of this document,

please make a contact with the following.

Technical Section, Technical Research Department

Shinko Welding Service Co., Ltd.

100-1, Miyamae, Fujisawa, Kanagawa 251-8551 Japan

(Phone：+81-466-20-3225 , FAX：+81-466-20-3238)

Technical Introduction...TECHNICAL INTRODUCTION SHINKO WELDING SERVICE CO., LTD. - 2 - 3. Technical...

Documents

Transcript of Technical Introduction...TECHNICAL INTRODUCTION SHINKO WELDING SERVICE CO., LTD. - 2 - 3. Technical...