welding inspector

DOC NO: 5Q&A-002-SA4 Revision: 0

QUALIFICATION & CERTIFICATION BOARD Date of Issue: 23 May 2011 Management System Manual IIW International Welding Specialist (IWS) Sample Questions and Answers

SA4 FABRICATION AND APPLICATION ENGINEERING Page 1 of 9

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QUESTION 1 1.1 What is the difference between Quality Assurance, Quality Control and Testing 6 marks

Quality assurance is a system of management activities performed to ensure that a process, item, or service is of the type and quality needed by the user. It deals with creating management controls that cover planning, implementation, and review of data collection activities. Quality control, on the other hand, is technical in nature and is implemented at the project level. It includes all the scientific precautions, such as calibrations and duplications, which are needed to ensure that data is of the proper quality and accuracy. Testing: The process of executing a system with the intent of finding defects.

1.2 What is the difference between a Welding Procedure Specification (WPS) and a Procedure Qualification Record (PQR)? 6 marks

A WPS is a document that describes how welding is to be carried out in production. They are recommended for all welding operations and many application codes and standards make them mandatory. It contains sufficient details to enable any competent person to apply the information and produce a weld of acceptable quality. The amount of detail and level of controls specified on a WPS is dependant on the application and criticality of the joint to be welded. Tests are performed to determine if the weld made to the procedure specification meets certain standards as established by the code or specification. If the destructive tests meet the minimum requirements the procedure then becomes a Procedure Qualification Record.

1.3 What is an Essential Variable in a welding process? Give four examples of essential

variables in the gas assisted FCAW process. 8 marks

Essential Variables are variables that have a significant affect on the mechanical properties of a joint. They must not be changed except within the limits specified by this code. e.g. Material thickness range, Material Group etc.

Material. Filler Metal Specification and Classification (size may vary within limits). Current Type and Polarity Shielding Gas composition Position of Welding Wire feed speed range Arc voltage

1.4 List the three stages in the development of welding procedures

3 marks The proposed welding procedure The procedure qualification record-PQR The welding procedure specification- WPS




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QUESTION 2 2.1 (i) Calculate the filler material cost per meter for a welding job given the following data, as

below. 10 marks DATA Parent Material: Carbon steel Equal 12 mm leg lengths Welding Process: GMAW Density of steel = 7.85 x 103 kg/m3 90 fillet weld Cost of filler material = $8/kg Wire diameter = 1.2 mm Deposition Efficiency = 90% Note: List any assumptions that you make.

Volume of weld metal convert mm to metres = Area of cross section x Length = x 0.012 x 0.012 x 1 = 0.000072m Weight of weld = Volume x Density = 0.000072 x 7.85 x 1000 = 0.5652 kg Actual wire used = Weight of weld metal Deposition efficiency = 0.5652 0.9 (90%) = 0.628 kg Total cost of consumables = Cost per kg x Actual weight of consumable used = 0.628 x $8 = $5.02

ii) How many meters of weld will a 15 kg spool of wire complete? 5 marks

Total meters of weld = 15 kg/C = 25 m




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2.2 Calculate the labour cost and the filler metal cost for a welding job given the following data, as

below. 10 marks

DATA Weld Joint type: T joint Single pass fillet welds on both sides of equal length (no preparation) Weld leg length: 8 mm (equal) Total weld length on each side: 1500 mm Material: Carbon steel Welding Process: GMAW Wire diameter = 1.2 mm Deposition Efficiency = 95% Deposition Rate = 4.1 kg/hr Density of steel = 7.85 x 103 kg/m3 Cost of filler material = $5/kg Hourly labour rate (including overhead) = $50 Operator Factor = 40%

Area of the cross section of a fillet weld 0.8 is 8mm in cm = x Base x Height divide 8mm by 10 = x 0.8 x 0.8 = 0.32 cm to give 0.8cm Volume of weld metal = Area of cross section x Length = 0.32 x 150 = 48cm Weight of weld metal = Density x Volume = 7.85 x 48 1000 = 0.38kg Actual weld metal deposited = Weight Deposition efficiency = 0.38 0.95 = 0.4kg Filler metal cost = Actual weld metal x Cost of filler metal = 0.4 x 5 = $2.00 Arc on time = Weld metal deposited Deposition rate = 0.4 4.1 x 60 (mins) = 5.9 mins




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Labour hours = Arc on time Operator factor = 5.9 0.4 = 14.75 Labour cost = Labour hours x Labour rate = 14.75 60 (mins) x 50 ($) = $12.29 Therefore for both welds of the same size Filler metal cost total = $2.00 x 2 = $4.00 Labour cost = $12.29 x 2 = 24.58

2.3 What would be an effective way of reducing the overall cost of producing the welds in question 2.2? Justify your answer with a sample calculation. 4 marks

Increase the operator factor up from 40% by either automating the process or by motivating the

welder eg. Increase from 40% to 50%

Labour hours = Arc on time / Operator factor = 5.9/0.5 = 11.8 mins Labour cost = Labour hours x Labour rate = 11.8/60 x 50 = $9.83 Therefore for both welds of same size: Filler metal cost total = $2.00 x 2 = $4.00 Labour cost = $9.83 x 2 = $19.66 Total cost = $23.66 vs $28.58, save 17% on the cost of producing the weld. Other changes such as increasing deposition rate or reducing labour rate.

QUESTION 3 3.1 List six safe working practices for welding in a fabrication shop. 8 marks Safe working practices:

Regular checking and maintenance of equipment Training Use of suitable safety devices Ensuring safe methods and procedures are known and observed PPE Periodic review of control procedures Pre-requisites: Know and use safe procedures, if in doubt ask Maintain equipment Ensure fume control/ventilation systems work Housekeeping Make any unsafe condition safe before working Signpost dangerous areas Adequate lighting Discourage or forbid smoking Sign post or tag defective equipment, initiate maintenance




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3.2 List three mechanical tests that could be used in qualifying a welding procedure. 8 marks

Nick break test Bend test Charpy test

3.2 List three alternatives to assessing a welded test piece that could be used in qualifying a welding

procedure. 6 marks The possible methods are specific to each standard/code and include:

Welding and assessing a (production) component or special test piece that replicates production welds. Also known as a pre-production welding test.

Previous experience. Relevant evidence is required such as authentic documentation (typically a WPS and/or test and inspection results).

Standard welding procedure. A procedure qualified by an authority (e.g. an examining body) and made available to a fabricator/manufacturer.

Prequalified. A procedure is developed in accordance with the requirements of the standard/code, minimal testing is required (a macro only for AS/NZS 1554).

Qualification based on the use of tested welding consumables. Similar to prequalified method, applicable to materials that do not deteriorate significantly in the heat affected zone.

3.3 List two specific weld/material defects that can be found using each of the following NDT methods

and give two advantages and two limitations of each NDT methods. a) Liquid Penetrant Inspection.

i) Two specific defects that can be found 2 marks

Surface cracks which may be missed by naked eye. Porosity exposed to the surface.

ii) Two advantages 2 marks

Economical inspection method. Aid to visual inspection. Portable. Can be used to inspect a wide a wide range of materials and components.

iii) Two limitations 2 marks

Access is required for surface preparation and cleaning. Surface condition must be satisfactory. Non relevant indications from irregular surfaces. Will only detect surface breaking flaws. The flaw MUST be clean.

b) Radiographic Inspection.

i) Two types of defects that can be found 2 marks

Porosity Tungsten inclusions Underfill Lack of penetration Crack and lack of fusion if orientated correctly to the energy beam




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ii) Two advantages 2 marks

Good volumetric inspection. Can detect surface and sub-surface flaws. Permanent results, e.g. radiograph. Good quality control method.

iii) Three limitations. 3 marks

Equipment can be bulky. Radiation hazard, e.g. harmful. Testing area needs to be controlled. Access required to both sides of the material. May not detect critical defects, e.g. cracks or lack of fusion. Radiographs need interpreting by an experienced person. Gamma results inferior to x-ray results.

. QUESTION 4

4.1 List two specific weld/material defects that can be found using each of the following NDT methods

and give two advantages and two limitations of each NDT methods. a) Magnetic Particle Inspection.

i) Two specific defects that can be found 2 marks Surface cracks which may be missed by naked eye. May give indication of sub-surface flaws.

ii) Two advantages of magnetic particle inspection 2 marks Relatively low cost. Portable, Gives clear indication.

iii) Two limitations of magnetic particle inspection 2 marks Only surface cracks detected with certainty. Can be used only on ferromagnetic Materials. Can give spurious indications. No permanent record




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b) Ultrasonic Inspection.

(i) Two types of sub surface defects that can be found 2 marks All sub-surface defects. Laminations

(ii) Two advantages of ultrasonic inspection 2 marks Very sensitive. Can detect defects too small to be discovered by other methods. Portable equipment. Access required to only one side.

iii) Two limitations of ultrasonic inspection. 2 marks Permanent record is difficult to obtain. Requires high skill level.

4.2 i) Define a crater crack or star crack with the aid of a sketch. 4 marks

A surface intersecting form of hot cracking in the crater of the weld stop. ii) How is it formed and how can it be prevented? 4 marks Crater cracks occur in the crater when the welding arc is improperly terminated. An incorrect manipulative technique is applied that does not allow for crater shrinkage. Prevent by: Improve the welding technique for crater fill Use run off tabs Use devices that provide for the incremental decrease of welding current iii) How can it be detected and be repaired? 2 marks Detect by: Visual inspection or by surface NDT methods Also by radiography and ultrasonic examination Repair by grinding/gouging followed by NDT




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QUESTION 5 5.1 Regulations typically require employers to manage significant hazards in the place of work. Identify

the measures that can typically be used by an employer: 4 marks

Identifying hazards - recognising things which may cause injury or harm. Assessing the hazard - evaluating whether the hazard is significant and the likelihood

and degree of injury or harm occurring to a person if they are exposed to a hazard. Controlling the hazard - by taking all practicable steps to eliminate, isolate, or minimise

significant hazards. Monitoring any exposure - to a hazard that has been minimised

5.2 Define an underbead cold crack. Explain briefly why it occurs.

Definition: A crack in the un-melted parent metal of the HAZ. Typically occurs under the weld bead.

Cause: Hydrogen embrittlement Prevention: Use hydrogen controlled electrodes and/or preheat Repair: (generally found using NDT). Remove and reweld.

5.3 State 2 limitations of the dye penetrant inspection method 2 marks

Access is required for surface preparation and cleaning. Surface condition must be satisfactory. Non relevant indications from irregular surfaces. Will only detect surface breaking flaws. The flaw MUST be clean.

5.4 What are usually the basic elements of a weld repair procedure? 4 marks

In general terms, a welding repair involves: a. Cleaning the joint area b. Complete removal of the defect (confirm using NDE) c. Applying appropriate preheat d. Welding with appropriate process, consumable and technique (controlling interpass

temperatures). ('appropriate' means suitable for the alloys being repaired and may not apply in specific situations)

e. Applying appropriate PWHT f. Dressing the weld g. Carrying out NDE to ensure no further defects have been introduced h. Applying protective treatments as required




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QUESTION 6 The following questions have multiple-choice answers and are worth 2 marks each. Only one answer is correct. Tick only one. If two boxes are ticked, no mark will be awarded. 6.1 How would operational techniques that are used to fulfil the requirements for the outcome of weld

quality be defined? a. Quality Audit b. Quality Assurance c. Quality Control d. Quality management 6.2 A company uses a Quality Manual to:

a. Describe the production process b. Organize NDT inspection of welded products c. Describe the quality assurance policy and quality

control system adopted by the company. d. Present operating procedures

6.3 What is defined by the ISO 14731 standard? a. Method of welder certification for welding of steel b. Method of welders certification for welding of aluminium c. Tasks and responsibilities of welding coordinators d. Conditions for quality assurance for workshop welding operations

6.4 What is defined by AS/NZS ISO 3834 standard? a. Method of welder certification for welding of steel b. Method of welders certification for welding of aluminium c. Tasks and responsibilities of welding coordinators d. Conditions for quality assurance for workshop welding operations

6.5 Which of the following tests is not generally required when qualifying a WPS according to ISO

15614-1 or AS/NZS 1554.1? a. Tensile test b. Bend test c. Chemical analysis d. Visual inspection

6.6 A highly constrained weld joint normally causes:

a. An increase of the residual stresses b. A decrease of the residual stresses c. A decrease of the distortion d. None of the above

6.7 Organization and equipment selection in a welding workshop depends mainly on:

a. Type of the product being fabricated b. Welding consumable selection c. Suppliers recommendation d. Welders decision




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6.8 According to which criteria would you select the level of protective lens shade in a welding helmet: a. According to the light conditions in the workshop. b. According to the level of back scattered infrared radiation c. According to the welding process used. d. According to the instructions of the welding supervisor.

6.9 Thermal crayons indicate reaching a measured temperature by:

a. Change in colour or melting of trace. b. Disappearing of trace from the material surface. c. Immediate evaporation of trace. d. Doubling of trace width.

6.10 For ultrasonic testing, what is the name of the indication that is caused by the opposite side of the

test piece? a. Initial pulse. b. Back wall echo. c. Flash back. d. Main sound beam.

6.11 The term deposition rate means:

a. The travel speed at which a weld is made manually. b. The weight of metal deposited in a unit of time. c. The speed at which an automatic process travels along the joint. d. None of the above.

6.12 After a defect has been found and ground out, which method would be best to confirm that the

defect has been fully removed: a. Dye penetrant or magnetic particle testing. b. Acoustic emission. c. Radiography. d. Ultrasonics.

6.13 What is the first step to repair a defective part?

a. Choosing the repair method. b. Choosing the most suitable electrode. c. Consider the economic viability. d. Cleaning the damaged area.

6.14 Which of the following methods are to identified as NDT methods?

a. Radiography. b. Bend test. c. Fracture test d. None of the above.

6.15 Visual inspection is unlikely to find the following defect: a. Undercut. b. Overlap c. Lack of inter-run fusion d. Surface porosity.

QUESTION 1 QUESTION 2 DATAQUESTION 3 QUESTION 4 QUESTION 5 5.3 State 2 limitations of the dye penetrant inspection method 2 marksQUESTION 6

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