UDDEHOLM TOOL STEELS FOR FORGING APPLICATIONS · PDF filetooling application hot work tooling...

TOOLING APPLICATION HOT WORK TOOLING 1

UDDEHOLM TOOL STEELS FOR

FORGINGAPPLICATIONS

TOOLING APPLICATION HOT WORK TOOLING2

This information is based on our present state of knowledge and is intended toprovide general notes on our products and their uses. It should not therefore beconstrued as a warranty of specific properties of the products described or awarranty for fitness for a particular purpose.

Classified according to EU Directive 1999/45/ECFor further information see our “Material Safety Data Sheets”.

Edition 3, revised 19.2016, not printed

© UDDEHOLMS ABNo part of this publication may be reproduced or transmitted for commercialpurposes without permission of the copyright holder.


CONTENTS

Hot forging of metals 4

Warm forging 7

Progressive forging 8

Effect of forging parameters on die life 10

Die design and die life 11

Requirements for die material 14

Manufacture and maintenance of forging die 16

Surface treatment 17

Tool steel product programme – general description 19 – chemical composition 20 – quality comparison 20

Tool steel selection chart 21

Cover illustration: Connecting rod forging tool.

Most of the photos are coming from Arvika Smide AB, Sweden and FiskarsBrands Finland Oy Ab

Selecting a tool steel supplier is a key decision for all parties, including the tool

maker, the tool user and the end user. Thanks to superior material properties,

Uddeholm’s customers get reliable tools and components. Our products are always

state-of-the-art. Consequently, we have built a reputation as the most innovative

tool steel producer in the world.

Uddeholm produce and deliver high quality Swedish tool steel to more than 100,000

customers in over 100 countries. We secure our position as a world-leading supplier

of tool steel.

Wherever you are in the manufacturing chain, trust Uddeholm to be your number

one partner and tool steel provider for optimal tooling and production economy.

Quite simply, it pays to go for a better steel.


HOT FORGINGOF METALSIn hot forging a heated up billet is pressedbetween a die set to a nearly finished product.Large numbers of solid metal parts are producedin aluminium alloys, copper alloys, steel orsuper-alloys where irregular shapes need to becombined with good mechanical properties.The main methods of drop forging are hammerforging and press forging.

HAMMER FORGING

Hammer forging is characterized by a very shortcontact time and very rapid rate of increase offorce with time (impact loading). The cumulativecontact time for the bottom die can be fairly longif one includes the time between blows. How-ever, since a lubricant with “blow-out” effect isnormally used with hammers, effective contactbetween the part and the die only occurs duringthe actual forging blow.

These features imply that impact toughnessand ductility are important properties for diesteel to be used in hammer dies. This does not

mean to say that wear resistance is not impor-tant, particularly in smaller dies, which in factnormally fail as a result of wear. In hammerforging, there is a lot to be said for using insertsof a more wear-resistant die steel which areshrink fitted into a tough holder material.

For larger, high-production hammer dies,which may be resunk a number of times, it isimportant that the die steel used has sufficienthardenability that the later cavities are not sunkin softer material with inferior wear resistance.

PRESS FORGING

In press forging, the contact time under pres-sure is much longer, and the impact load ismuch lower than in hammer forging. In generalterms, this means that the heat resistance andelevated temperature wear resistance of the diesteel are relatively more important than theability to withstand impact loading. However,one must optimize impact toughness andductility in relation to wear resistance; thisapplies particularly for large press dies whichare not supported from the sides. Since thesurface temperature of press dies will during


GROSS CRACKINGForging dies might fail as a result of some formof gross cracking. This may occur during asingle cycle or, as is most common, over anumber of cycles; in the latter instance, thecrack growth proceeds via a high-stress fatiguemechanism. Gross cracking is more frequent inhammer blocks than in press tooling, becauseof the greater degree of impact.

WEARIf all other damage mechanisms are sup-pressed, a forging die will ultimately wear out(parts out of tolerance). Wear occurs when thework material plus oxide scale glide at highvelocity relative to the cavity surface under theaction of high pressure. It is most pronouncedat convex radii and in the flash land. Wear isincreased drastically if the forging temperatureis reduced (higher flow stress for the workmaterial). The explosion which occurs via

TYPICAL DIE FAILURES

The deterioration of forging dies is usuallyassociated with several processes which mayoperate simultaneously. However, one of thesenormally dominates and is the ultimate cause offailure. In general, four distinct damage mecha-nisms can be distinguished:• wear• mechanical fatigue and gross cracking• plastic deformation• thermal fatigue cracking (heat checking)

Different damage mechanisms can dominate indifferent parts of the cavity.

Thermal fatigue Wear Wear

combustion of oil-based lubricant in the con-fined space between forging and die can alsogive rise to a type of erosive wear.

Wear.

Thermal Cracking Wear Plastic fatigue deformation

service generally be higher than for hammerdies, it is important that the die surface is notexcessively chilled by lubrication. Otherwise,premature heat checking or even thermal shockcracking may result.


Gross cracking is a failure condition which canalmost always be rectified. Normally, crackinglies in one or more of the following:• overloading, e.g. work material temperature

too low

• die design, e.g. too sharp radii or too thin wallthickness

• inadequate preheating of the die

• inadequate toughness of die steel (wrongselection)

• too high hardness of die material

• poor quality heat treatment/surface treatment

• inadequate die support/alignment

PLASTIC DEFORMATIONThis occurs when the die is locally subjected tostresses in excess of the yield strength of thedie steel. Plastic deformation is quite commonat small convex radii, or when long thin toolingcomponents e.g. punches, are subjected to highbending stresses.

The following can be the cause of plasticdeformation in forging dies:

• too low billet temperature (high flow stress ofwork material)

• inadequate hot strength of die steel

• die temperature too high

• die material too soft

Totally cracked die.

THERMAL FATIGUE CRACKINGThis results if the surface of the cavities issubjected to excessive temperature changesduring the forging cycle. Such temperaturechanges create thermal stresses and strains atthe die surface which eventually lead to crack-ing via a low-cycle fatigue mechanism (heatchecking).

Thermal fatigue cracking is increased by thefollowing factors:• cavity surface at too high temperature

(excessive billet temperature and/or longcontact time)

• excessive cooling of die surface betweenforgings

• inadequate preheating of die• wrong selection of die steel and/or poor heat

treatment

All these factors will increase the differencebetween maximum and minimum temperature inthe die surface.


WARM FORGINGWarm forging is a precision forging operationcarried out at a temperature range between550–950°C (1020–1740°F). It is useful for forgingof details with intricate shapes, with desirablegrain flow, good surface finish and tighterdimensional tolerances than if hot forged.

The weight of the forged piece is between0.1–50 kg (0.22–110 lbs) and the production rateabout 10–40 pieces per minute. The contacttime is about 200 ms and the mechanical loadsat 600°C (1110°F) are 3 to 5 times higher than inhot forging. Automatic multistation presses withintegrated cooling/lubricating systems are oftenused.

UPSETTING

Tube Rod

FORWARD EXTRUSION

Punch

Die

IRONING

LATERAL EXTRUSION

HEADING

OPEN DIE EXTRUSION

Reducing

BACKWARD EXTRUSION

Can

Typical processes in warm forging.

DIE MATERIAL PROPERTIES

The properties profile required for tool steel inforging dies depends to some extent on thetype of forging operation, on the work materialand on the size of the part, depth of cavity etc.However, a number of general characteristicswill always be required in all forging operations.The particular die damage mechanism are givenin parentheses.

• Sufficient hardness and ability to retain this atelevated temperatures—temper resistance(wear, plastic deformation, thermal fatiguecracking).

• Enhanced level of hot tensile strength and hothardness (wear, plastic deformation, thermalfatigue cracking).

• Good toughness and ductility at low andelevated temperatures (gross cracking,thermal shock cracking, thermal fatiguecracking). It is important that the die steelexhibits adequate toughness/ductility in alldirections.

• Adequate level of fatigue resistance (grosscracking).

• Sufficient hardenability (retention of wearresistance etc. if the die is resunk).

• Amenability to weld repair.

• Good machinability, especially prehardeneddie blocks.

Workmaterial


PROGRESSIVEFORGINGIn progressive forging a large number of sym-metrical, precision-forged parts with forgedweights of up to about 5 kg (11 lbs) are pro-duced. The fully automatic process involvessupplying hot rolled bars at one end of the line,

heating them inductively, cutting them to therequired size, shaping them in 3–4 stages anddischarging finished forgings at the other end ofthe line.

Depending on the weight of the forgings,production capacity is between 50 and 180 perminute.

TYPICAL FAILURES

Tool parts used in the progressive forging, suchas die, stem, stem holder, punch and counterpunch-ejector are subjected to very highstresses.

As the production speed is very high, the dieparts need to be water-cooled to protect themagainst overheating. Nevertheless, despiteintensive cooling, the tool surfaces can bestrongly heated, even by the brief contact, withthe hot metal being forged.

As a result of this alternate heating andcooling the die parts are subjected to extremelyhigh thermal fatigue. The degree of the thermalfatigue cracking constitutes a measure of thematerial life.

An additional factor is the degree of hot wearof the material, which depends on the surfacetemperatures and the mechanical stresses onthe die.

TOOL MATERIAL PROPERTIES

The required properties profile of the hotforming die and die parts are:

• high temperature strength and good temperresistance to withstand hot wear and thermalfatigue cracking

• good thermal conductivity to withstandthermal fatigue cracking

• good hot ductility and toughness to resistinitiation and rapid spread of thermal fatiguecracking

TYPICAL FAILURES

During the warm forging operation the tool partsare exposed to rather high temperature, highmechanical loads and intensive cooling.

As a result of this alternate heating andcooling the tool parts are subjected to highthermal fatigue.

An additional factor is the degree of hot wearof the material, which depends on the surfacetemperatures and the mechanical stresses onthe tool.

TOOL MATERIAL PROPERTIES

The tool parts are subjected to both highmechanical stresses and high thermal stresses.For these reasons a tool steel has to be chosenwhich has a good temper resistance, good wearresistance, high hot yield strength, good thermalconductivity and good thermal fatigue resist-ance. A warm forging steel must exhibit aproperties profile which is in between the typicalproperties profiles for hot work and cold worksteel.


1

1

2

5

7

3

4

6859 6

6a

6

6a

8

7a5

8 911

10

1 2 3 4 5 6 6a 7 7a 8 91011

Two-part cutting bushWork metalStopperCutterBlankStem/PunchHollow punchBolsterCounter punch-ejectorDieWaste metalPiercerProduct

FORGING IN A FULLY AUTOMATIC PROCESSS


EFFECT OF FORGINGPARAMETERS ONDIE LIFEApart from the influence of the actual diematerial and its heat treatment/surface treat-ment, a number of parameters related to theforging operation affect die life:

• billet temperature

• billet shape and surface condition

• work material

• cavity stress level and contact time

• type of forging operation

• type of lubricant

BILLET TEMPERATURE

Reduced billet temperature in forging is favour-able from the viewpoint of mechanical proper-ties in the forged part itself. This is particularlyimportant if the components are not heattreated after forging. However, the higher flowstress of the work material, which is associatedwith a reduced forging temperature, results inboth increased wear and a higher risk for plasticdeformation. Further, since the forging loadsincrease, the probability for gross cracking isenhanced.

TYPICAL HOT FORGINGTEMPERATURES

STEEL 1050–1250°C (1920–2100°F)

CU-ALLOYS 650–800°C (1200–1470°F)

AL-ALLOYS 350–500°C (660–930°F)

TI-ALLOYS 800–1000°C (1470–2010°F)

BILLET SHAPE ANDSURFACE CONDITION

The greater the difference between the shape ofthe billet and that of the final forging, the greateris the degree of wear because the relativemovement between work material and die mustincrease. Likewise, hard, adherent scale on thebillet surface will increase wear, especially if thegliding distance is large.

WORK MATERIAL

The higher the flow stress of the work material,the faster is die deterioration due to wear and/orplastic deformation, at the same time as the riskfor gross cracking is increased. Hence, stainlesssteel is more difficult to forge than carbon steelat the same temperature.

Forgeability of different types of material.

Low Moderate High

High

Moderate

Low

Constructural

Al–Mg-alloys

Stainless

Ti-alloys

Ni- andCo- alloys

FORGEABLILITY

IMPACT ENERGY OR PRESS POWER


DIE DESIGNAND DIE LIFEAssuming that the forging equipment is in goodcondition (properly adjusted and withoutexcessive play in the ram guide system), thenadherence to the following “die design” princi-ples will reduce the risk for catastrophic diefailure:• proper die support

• dovetails, if used, should be properly dimen-sioned, have sufficiently large radii and beproperly finished (grinding marks should betangential and not axial), see figure below.

• sufficient wall thickness, and sufficientmaterial below the cavity and betweenindividual cavities

• adequate radii and fillets in the cavity

• proper dimensioning of flash land and gutter

• proper design of parting plane and, if used,die locks

• correct use and design of setting plugs,punches and knockout pins

• sufficiently large cushion-face area in hammerforging in relation both to die block thicknessand to the capacity of the hammer used

Improper die support, insufficient materialthickness in the die and too small radii are allvery common reasons for a die failing cata-strophically by cracking, and will be furtherenlarged upon.

CAVITY STRESS LEVELAND CONTACT TIME

An increased stress level in the cavity, can befound, for example, in high precision forging,and has the following consequences:• increased stress in the tool with higher risk for

deformation or gross cracking

• increased heat transfer from billet to die(heat checking)

• more pronounced wear

Prolonged contact between billet and die duringforging results in accelerated wear and a greaterrisk for heat checking. For very long contacttimes, the surface layer of the tool may becomeso hot that it transforms to austenite. Crackingproblems can then be experienced if this layerrehardens during the cooling part of the cycle.

TYPE OF FORGING OPERATION

Because of the much higher impact load,hammer dies tend to fail by cracking to anextent which is greater than in press forgingwhere the loading rate is lower. Thermal fatigue(heat checking) is more common in powderforging and other near-net-shape forgingprocesses involving long contact times.

TYPE OF LUBRICANT

Oil-based lubricants can give rise to excessivewear/erosion due to the explosion-like combus-tion of the oil between billet and cavity. On theother hand, water base lubricants cool the diesurface to a greater extent which increases therisk of thermal fatigue cracking.

Grinding of dove-tail radii.


DIE SUPPORT

It is very important that the die is properlysupported underneath by a perfectly flat back-ing surface with sufficient hardness. Concavedepressions in the support surface immediatelyunder the die cavity are particularly deleteriousbecause they exaggerate the tensile stresses atradii.

Proper backing is especially important inhammer forging because there is usually no sidesupport in this case. When dies of greatlydifferent dimensions are used on the samepress or hammer, it is essential to remove anycavities in the backing block or plate whenswitching from a small to a large die.

For press forging, side support of the die isdesirable but this is not always possible. Shrinkfitting of inserts into a massive holder providesthe best security against cracking in press dies.

FILLET RADII

The greatest tensile stresses in a forging dieoccur at the radii between the sides and bottomof the cavity. The smaller the radius, the higherthe stresses. In general, the forging should bedesigned so that die fillet radii less than 2 mm(0.08 inch) can be avoided. For deeper cavities,>50 mm (>2 inch), this radius limit needs to beincreased to 5 mm (0.2 inch).

It is especially important during die makingthat radii are ground and polished with grindingmarks, if any, in the tangential direction. Inparticular, EDM residues, which may containcracks, must be removed completely at radii(and preferably from the rest of the die as well).If this is not possible, then the die should atleast be retempered at 25°C (50°F) below theprevious tempering temperature.

DIE MATERIAL AND WALL THICKNESS

A number of more or less empirical methods ordimensioning of forging dies are available,which range in complexity from simple “rule ofthumb” to fairly advanced nomograms with atheoretical base. However, there is no doubtthat the stresses imparted to the die by a givenforging machine increase profoundly as the diedimensions are decreased.

Minimum height (Hmin) of hammer dies with amaximum depth of cavity (hmax).

hmax

Hmin

Hmin,inch mm

16 400

14 350

12 300

10 250

8 200

6 150

4 10010 25 50 75 100 125 150 mm 0.4 1 2 3 4 5 6 inch

hmax

As a rule of thumb for solid die blocks in pressforging the thickness below the cavity should beat least 1.5 x cavity depth.

As a minimum wall thickness in hammerforging the recommendations are according tothe table below.

t

h

Depth of cavity (h) mm inch

Distancecavity to outeredge of a die (t) mm inch

6 0.2 12 0.510 0.4 20 0.816 0.6 32 1.325 1.0 40 1.640 1.6 56 2.263 2.5 80 3.2

100 3.9 110 4.3125 4.9 130 5.1160 6.3 160 6.3

Mnimum wall thickness (t) recommended in hammerdies between cavity and outer edge.


REQUIREMENTSFOR DIE MATERIALHARDENABILITY

In large press or hammer dies made from pre-hardened die steel, it is important that thehardness is uniform throughout the block. If thedie steel has too low hardenability, the block willbecome softer away from its outer surface anddie life for deep cavities or after progressiveresinking will be impaired.

TOUGHNESS AND DUCTILITY

The surface of the cavity can during use easilydevelop small cracks or other blemishes whichmay propagate in an unstable manner under theaction of the high forging stresses, especially atradii etc. Notch toughness indicates the abilityof the die material to resist crack developmentfrom such defects.

All products, in the Uddeholm tool steelprogramme for the forging industry, are charac-terized by the highest levels of toughness andductility in all directions in the bar or block.Hence, the forger can rest assured that theresistance to gross cracking is the highestpossible in dies made from Uddeholm die steel.

Proper die preheating will considerably reducethe risk for catastrophic failure via cracking.

TEMPER RESISTANCE

The better the steel retains its hardness as thetemperature or the time increases, the better itstemper resistance.

Temper resistance can be assessed from thetempering curve for a hardened tool steel. Inthis, the hardness at room temperature is

plotted against tempering temperature for giventempering time. Another method of presentingtemper resistance data is to plot room tempera-ture hardness against time at a given temperingtemperature.

HOT STRENGTH AND HOT HARDNESS

In contrast to temper resistance, which isdefined in terms of hardness at room tempera-ture, hot strength and hot hardness refer toproperties at high temperature. In general,improved temper resistance is associated withincreased hot strength and hot hardness. It canbe pointed out that good hot hardness and hotstrength are important prerequisites for en-hanced wear resistance at elevated tempera-tures.

A high level of hot hardness and hot strengthis also important in order to achieve adequateresistance to thermal fatigue cracking.

FATIGUE RESISTANCE

Uddeholm tool steel for forging dies are pro-duced to the highest possible quality standards,especially with regard to freedom from non-metallic inclusions. This imparts a degree offatigue resistance which is adequate for eventhe most demanding applications where forgingdies are subjected to cyclic loading with highmaximum loads.


QRO 90SUPREME

DIEVAR

ORVAR SUPREME

VIDAR SUPERIOR

ORVAR SUPERIOR

HOT STRENGTH

100 200 300 400 500 600°C

200 400 600 800 1000 1200°F

TESTING TEMPERATURE

DIEVAR

ORVAR SUPREMEand ORVAR SUPERIORVIDAR SUPERIOR

NOTCH TOUGHNESS

100 200 300 400 500°C

200 400 600 800 1000°F

TESTING TEMPERATURE

QRO 90 SUPREME


MANUFACTUREAND MAINTENANCE OFFORGING DIEMachinability, weldability and, when applicable,response to heat treatment and surface treat-ment are important parameters influencing therelative ease of manufacture and maintenanceof forging dies.

MACHINABILITY

Machinability is a vital consideration whenforging dies are machined from prehardened dieblocks.

The tool steel for forging applications fromUddeholm are characterized by freedom fromoxidic inclusions and a uniform microstructure.These features, in combination with the lowhardness in the annealed condition usually 170–200 HB, are to ensure excellent machinability.

facture are “Grinding of tool steel” and “Electri-cal Discharge Machining (EDM) of tool steel”.

HEAT TREATMENT

If forging dies are manufactured from die steel inthe annealed condition, then the tool mustsubsequently be heat treated in order that thesteel develops its optimum combination ofhardness, toughness, heat resistance and wearresistance.

These properties are controlled throughproper choice of austenitizing temperature,cooling conditions during hardening andtempering temperature and time. The Uddeholmbrochure “Heat treatment of tool steel” will beworth consulting.

For forging dies, where toughness is of theutmost importance, it is essential that thecooling rate during hardening is sufficientlyrapid that undesirable microconstituents such

Even if these grades are supplied prehardened,the extreme cleanliness and microstructuralhomogeneity ensure that machining can nor-mally be carried out without difficulty.

For all products, advanced process controlguarantees that the variations in machiningcharacteristics are minimal from batch to batch.

Uddeholm’s product brochures give detailedinformation regarding machining of the prod-ucts. Other Uddeholm publications worthconsulting in the context of forging die manu-

as pronounced grain-boundary carbide precipi-tation, pearlite and coarse upper bainite can beavoided. Furthermore, the austenitizing condi-tions should be such that excessive graingrowth can not occur, since this is detrimentalas regards to toughness. Because forging diesare sometimes EDM’d extensively after heattreatment, there is generally no problem to copewith the greater dimensional change anddistortion which results when the rate of coolingduring hardening is rapid. Remember, however,

10 15 25 35 65 600°C/min.50 60 75 95 150 1110°F/min.

NOTCH TOUGHNESS

Notch toughness of Uddeholm Orvar Supreme, 44–46 HRC, as a function of quench rate.


Bending strength of Uddeholm Orvar Supreme as a function of nitriding depth.

WELD REPAIR OF FORGING DIES

Cracked or worn forging dies are often refur-bished via welding. This is especially true in thecase of large dies where the tool steel itselfrepresents a considerable portion of the totaldie cost.

Further information can be obtained from theUddeholm publication “Welding of tool steel”.

SURFACE TREATMENTThe cavity in forging dies is quite often surfacetreated in order to enhance wear resistance.

NITRIDING

Nitriding is a thermochemical treatment giving ahard surface layer which is very resistant towear. In favourable cases, the process alsorenders a compressive residual stress in thesurface of the die which helps counteract heatchecking.

However, the nitrided layer is very brittle andmay crack or spall when subjected to mechani-cal loading, especially impact loading. Nitridingis usually carried out by one of four methods,nitrocarburizing in salt-bath or gas, gas nitridingor plasma (ion) nitriding.

Before nitriding, the tool should be hardenedand double tempered, the latter at a tempera-ture at least 25–50°C (50–90°F) above thenitriding temperature.

The surface hardness attained and thethickness of the nitrided layer depend on thenitriding method, nitriding time and the charac-ter of the steel being treated. Typical data canbe found in the Uddeholm product brochuresfor the different tool steel.

Nitriding to layer thicknesses >0.3 mm(>0.012 inch) is not to be recommended forforging dies. The reason is that the nitrided layeris brittle and easily cracks during service. Theunderlying steel can not resist the propagationof such surface cracks if the layer thickness istoo great and the entire die may fail catastrophi-cally. 0.3 mm (0.012 inch) maximum nitride layerthickness is a general recommendation; thismaximum value should be decreased if theimpression has very sharp radii or if the die steelis used at high hardness.

The formation of the so-called “white layer”should also be avoided because of brittlenesss.

BENDING STRENGTH

0.05 0.15 0.30 0.45 mm 0.0016 0.006 0.012 0.018 inch NITRIDING DEPTH

200°C (390°F)

20°C (70°F)

that EDM’d dies should always be given anadditional temper at about 25°C (50°F) belowthe previous tempering temperature. Detailedheat treatment recommendations for the variousgrades, in Uddeholm’s tool steel programme forforging dies, are given in the product brochurefor each individual product.


UDDEHOLMTOOL STEEL

Dievar

Unimax

Orvar 2 Microdized

Orvar Supreme/Orvar Superior

Vidar Superior

QRO 90 Supreme

Formvar

Alvar 14

Vanadis 23 SuperCleanVanadis 30 SuperClean

Uddeholm Dievar excels in almost all areas as a hot work tool steel. Theunparalleled toughness and ductility decrease the risk of cracks in the die.Together with the high thermal conductivity and good hot strength, thismakes Dievar the ideal choice for your workhorse dies. It meets therequirements of NADCA #207-2011.

When excessive wear is experienced in the die, Uddeholm Unimax shows itstrue qualities. At a recommended hardness of 56–58 HRC Unimax resistsabrasive wear, both hot and cold, and significantly increases the life of theforging die.

Uddeholm Orvar 2 Microdized is part of the Uddeholm basic range for forgingapplications. It is well-rounded steel with proven qualities and balancedproperties. Orvar 2 M has stood the test of time as a reliable forging toolsteel.

Uddeholm Orvar Supreme is well-rounded steel that has proven itself as agreat hot work tool steel for years. The combination of properties makes thisa solid choice for your tooling needs. It meets the requirements of NADCA#207–2011.

When cracking resistance is critical, Uddeholm Vidar Superior is a greatchoice for forging dies. It meets the requirements of NADCA #207–2011.

Uddeholm QRO 90 Supreme is perfect when the surface of the tool issubjected to excessive heat. The highest thermal conductivity in the Udde-holm hot forging steel range combined with the highest resistance to wear atelevated temperature make this advanced high strength steel a great choicefor long-lasting dies.

Uddeholm Formvar is a solid upgrade choice from H11/H13 forging dies.With good tempering back resistance and hot yield strength.

Uddeholm Alvar 14 is a pre-hardened grade suitable for hammer forging.The good toughness and ease of machining make this a good choice forbasic hammer forging needs.

PM-produced high speed steel. Recommended for forging applicationswhere very good wear resistance is needed.

TOOL STEEL PRODUCT PROGRAMMEFOR FORGING APPLICATIONSGENERAL DESCRIPTION


Dievar

Unimax

Orvar 2 Microdized

Orvar Supreme

Orvar Superior

Vidar Superior

QRO 90 Supreme

Formvar

Alvar 14

UDDEHOLMTOOL STEEL

PLASTIC PREMATURE HEATHOT WEAR DEFORMATION CRACKING CHECKING

SUPPLIED AISI ANALYSIS % HARDNESS

(W.-Nr.) C Si Mn Cr Mo V Others Brinell

Dievar – 0.35 0.2 0.5 5.0 2.3 0.6 – ~160

Unimax – 0.50 0.2 0.5 5.0 2.3 0.5 – ~185

Orvar 2 H13 Microdized (1.2344) 0.39 1.0 0.4 5.3 1.3 0.9 – ~180

Orvar Supreme H13 0.39 1.0 0.4 5.2 1.4 0.9 – ~180(1.2344)

Orvar Superior H13 0.39 1.0 0.4 5.2 1.4 0.9 – ~180

(1.2344)

Vidar Superior H11 modified 0.36 0.3 0.3 5.0 1.3 0.5 – ~180(1.2340)

QRO 90 Supreme – 0.38 0.3 0.8 2.6 2.3 0.9 Micro-alloyed ~180

Formvar – 0.35 0.2 0.5 5.0 2.3 0.6 – <229

Alvar 14 (1.2714) 0.55 0.3 0.7 1.1 0.5 0.1 Ni 1.7 ≤250 orprehardened

CHEMICAL COMPOSITION

UDDEHOLMTOOL STEEL

QUALITATIVE COMPARISON OF RESISTANCE OF BASIC PROPERTIES

The longer the bar, the better.


TOOL STEEL SELECTION CHARTGENERAL RECOMMENDATIONS

FORGING UDDEHOLM HARDNESS CAVITY APPLICATION STEEL GRADE RANGE DEPTH

HAMMERFORGING Solid die blocks Alvar 14 – Pre-hardened 400–440 HB max 20 mm

(0.8 inch)360–400 HB max 50 mm

(2 inch)320–360 HB max 150 mm

(6 inch)≤320 very deep

Inserts Vidar SuperiorDievarOrvar SupremeOrvar Superior 38–50 HRC

PRESS FORGING Dies DievarVidar SuperiorOrvar SupremeOrvar SuperiorQRO 90 SupremeUnimaxFormvar 38–57 HRC

WARM FORGING Tools UnimaxDievarFormvar 50–58 HRC*

PROGRESSIVEFORGING Tools QRO 90 Supreme

UnimaxDievarFormvar 48–54 HRC*

UPSET FORGING Tools UnimaxDievarFormvar 46–56 HRC

* Uddeholm PM grades can be used in some tool parts. Higher hardnesses can be used.


NETWORK OF EXCELLENCEUddeholm is present on every continent. This ensures you

high-quality Swedish tool steel and local support wherever

you are. We secure our position as the world’s leading

supplier of tooling materials.


UD

DEH

OLM

160402.75 / STR

OKIR

K KNA

PPEN 04.2016

Uddeholm is the world’s leading supplier of tooling materials.

This is a position we have reached by improving our customers’

everyday business. Long tradition combined with research and

product development equips Uddeholm to solve any tooling

problem that may arise. It is a challenging process, but the goal is

clear – to be your number one partner and tool steel provider.

Our presence on every continent guarantees you the same high

quality wherever you are. We secure our position as the world’s

leading supplier of tooling materials. We act worldwide. For us it is

all a matter of trust – in long-term partnerships as well as in

developing new products. Trust is something you earn, every day.

For more information, please visit www.uddeholm.com

UDDEHOLM TOOL STEELS FOR FORGING APPLICATIONS · PDF filetooling application hot work tooling...

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