Welding of Tool Steel - Uddeholm (eBook, 17 Pages)

7/29/2019 Welding of Tool Steel - Uddeholm (eBook, 17 Pages)

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WELDING

OF TOOL STEEL

T R E A T M E N T O F T O O L S T E E L

Wherever tools are made

Wherever tools are used


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Weldingof Tool Steel

2

This information is based on present state of knowledge and isintended to provide general notes on our products and their uses.It should not therefore be construed as a warranty of specificproperties of the products described or a warranty for f itness for aparticular purpose.

ContentIntroduction .......................................................... 3

General information onwelding of tool steel .............................................. 3

Welding methods for tool steel ............................ 4

The welding bay ................................................... 5

Filler-metal characteristics ................................... 6

Be careful as regards hydrogen! .......................... 9Elevated working temperature ............................ 10

Welding procedure ............................................... 11

Weld repair ofhot work tool steel ........................................... 14plastic mould steel ........................................... 15cold work tool steel .......................................... 16


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IntroductionThe weldability of steels with more than 0,2% car-bon is usually considered to be poor. Hence, toolsteels with 0,32,5% carbon are difficult to weld and

many steel suppliers will actuallyrecommend against welding. However, improvedquality of consumables, refined welding equip-ment, developments in welding technique and, notleast, improvements in tool steel quality have com-bined to render tool welding as a realistic possibil-ity, which can have considerable economic conse-quences.

Hence, Uddeholm recognizes that tool steelsoften need to be welded; this is especially true forexpensive tooling like die-casting dies, large forg-ing dies, plastic moulds, carbody dies and blanking

tools where repair and adjustment via welding ishighly cost-attractive in comparison with the ex-pense of producing new tooling.

The welding bay.

Generalinformation onwelding of tool steelTool steels contain 0,32,5% carbon as well as

alloying elements such as manganese, chromium,molybdenum, tungsten, vanadium and nickel. Themain problem in welding tool steel stems from its

high hardenability. Welds cool quickly once theheat source is removed and the weld metal andpart of the heat-affected zone will harden. Thistransformation generates stresses because theweld is normally highly constrained, with a con-

comitant risk for cracking unless great care isexercised.

In what follows, a description is given of thewelding equipment, welding technique and weldconsumables that are required in order to weldtool steel successfully. Of course, the skill andexperience of the welder is also a vital ingredient inobtaining satisfactory results. With sufficient care,it is possible to achieve weld repairs or adjust-ments which, in terms of tooling performance, arehardly inferior to that of the base steel.

Welding of tooling may be required for anyone

of the following reasons: Refurbishment and repair of cracked or worn

tooling

Renovation of chipped or worn cutting edges,e.g. on blanking tools

Adjustment of machining errors in toolmaking

Design changes.


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GAS TUNGSTEN-ARC WELDING

(GTAW OR TIG)

Principle

In MMA welding, the electrode rod from whichthe arc is struck is consumed during welding.

The electrode in TIG welding is made of tung-sten or tungsten alloy which has a very high melt-ing point (about 3300C/6000F) and is thereforenot consumed during the process(Fig. 2). The arc is initially struck by subjecting theelectrode-workpiece gas to a high-frequency volt-age. The resulting ionization permits striking with-out the necessity for contact between electrodeand workpiece. The tungsten electrode is alwaysconnected to the negative terminal of a DC powersource because this minimizes heat generation

and thereby any risk of melting the electrode. Cur-rent is conducted to the electrode via a contactinside the TIG-gun. Any consumables which arerequired during TIG-welding are fed obliquely intothe arc in the form of rod or wire. Oxidation of theweld pool is prevented by an inert-gas shroudwhich streams from the TIG tun over the electrodeand weld.

Power source

TIG welding can be performed with a regularMMA power source provided this is comple-

mented with a TIG control unit. The gun should bewater cooled and be capable of handling a mini-mum current of 250 A at 100% intermittence. A gaslens is also a desirable feature in order that theinert gas protection is as efficient as possible.Welding is facilitated if the current can be in-creased steplessly from zero to the optimum level.

SHIELDED METAL-ARC WELDING

(SMAW OR MMA)

Principle

An electric arc generated by a DC or AC powersource is struck between a coated, rod-like elec-trode and the workpiece (Fig. 1).

The electrodes consist of a central wire core,which is usually low-carbon steel, covered with acoating of pressed powder (flux). The constitutionof this coating is complex and consists of ironpowder, powdered ferro-alloys, slag formers and asuitable binder. The electrode is consumed under

the action of the arc during welding and drops ofmolten metal are transferred to the workpiece.Contamination by air during the transfer of moltendrops from electrode to workpiece and duringsolidification and cooling of the weld deposit isinhibited partly by slag formed from constituents inthe electrode coating and partly by gases createdduring melting of the electrode.

The composition of the deposited weld metal iscontrolled via the constitution of the electrodecoating.

Power source

For MMA welding, it is possible to use either anAC or DC power source. However, whichever isused, the source must provide a voltage andcurrent which is compatible with the electrode.Normal arc voltages are: Normal recovery electrodes: 2030 V High recovery electrodes: 3050 V

Uddeholm welding consumables are of normal-recovery type. A suitable power source for these isa DC unit with an open voltage of 70 V and whichis capable of delivering 250A/30 V at 35% intermit-tence.

METHODSManual Metal-arc welding (MMA)

Welding conv.

Welding rectifier

Electrode

Electrode holderPower source

+Pole

Pole

Fig. 1

Weld

Filler rod

+ Pole

Pole

Welding

rect.

METHODS

TIG-Welding

Workpiece

Shielding gas

Shielding gas

Fig. 2

Workpiece

Workpiece Weld

Slag

Moltenpool

Welding torch

Tungsten

electrodePower supply

Cooling water

Welding methodsfor tool steel


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PREHEATING EQUIPMENT

Tool steels cannot be welded at room temperaturewithout considerable risk for cracking and it isgenerally necessary to pre-heat the mould or die

before any welding can be attempted (see later).While it is certainly possible to weld tools success-fully by preheating in a furnace, the chances arethat the temperature will fall excessively prior tocompletion of the work. Hence, it is recommendedthat the tool be maintained at the correct tempera-ture using an electrical heating box supplied froma current-regulated DC source. This equipmentalso enables the tool to be heated at a uniform andcontrolled rate.

For minor repairs and adjustments, it is accept-able that the tool be preheated using a propanetorch. Hence, liquid propane cylinders should beavailable in the welding bay.

Electrical elements for an insulated preheating box.

GRINDING MACHINES

The following should be available:

Disc grinder with minimum 180 x 6 mmwheel (7 x 0,25 inch) for preparing the jointand grinding out of any defects which mayoccur during welding.

Flat grinder capable of25 000 rpm for grindingof minor defects and of the finished weld.

If a welded mould is subsequently to bepolished or photo-etched, it may be necessary tohave a grinder capable of giving a sufficientlyfine finish.

The welding bayIn order to be able to effect satisfactory weldingwork on tool steel, the following items of equip-ment are to be regarded as minimum require-

ments (over and above the welding equipment).

DRY CABINET

The coated electrodes used for MMA welding arestrongly hygroscopic and should not be allowed tocome into contact with anything other than dry air.Otherwise, the weld will be contaminated withhydrogen (see later). Hence, the welding bayshould be equipped with a dry cabinet for storageof electrodes. This should be thermostaticallycontrolled in the range 50150C (120300F).The electrodes should be removed from their con-

tainers and lie loose on racks.For welding of tooling outside the welding bay,

it will also be found useful to have a portableheated container in which the electrodes can becarried.

WORKBENCH

It is particularly important during critical weldingoperations, of the type performed with tool steel,that the welder enjoys a comfortable working posi-tion. Hence, the workbench should be stable, of

the correct height a sufficiently level that the workcan be positioned securely and accurately. It isadvantageous if the workbench is rotatable andadjustable vertically, since both these featuresfacilitate the welding operation.

Dry cabinet for storage of electrodes.


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Filler-metalcharacteristicsThe chemical composition of a weld deposit is

determined by the composition of the consumable(filler metal), the base steel composition and theextent to which the base material is melted duringwelding. The consumable electrode or wire shouldmix easily with the molten base steel giving adeposit with:

Uniform composition, hardness and response toheat-treatment

Freedom from non-metallic inclusions, porosityor cracks

Suitable properties for the tooling application inquestion.

Since tool steel welds have high hardness,they are particularly susceptible to cracking whichmay originate at slag particles or pores. Hence, theconsumable used should be capable of producing ahigh-quality weld. In a similar vein, it is necessarythat the consumables be produced with very tightanalysis control in order that the hardness aswelded and the response to heat treatment isreproducible from batch to batch. High-qualityfiller metals are also essential if a mould is to bepolished or photo-etched after welding. Uddeholmwelding consumables meet these requirements.

TIG filler rod is normally produced fromelectro-slag remelted stock while coated electrodesare of basic type, which are far superior to rutileelectrodes as regards weld cleanliness. Anotheradvantage with basis coated electrodes over those

of rutile type is that the former give a much lowerhydrogen content in the weld metal.

In general, the consumable used for weldingtool steel should be similar in composition to thebase material. When welding in the annealedcondition, e.g. if a mould or die has to be adjustedwhile in the process of manufacture, it is vital thatthe filler metal has the same heat treatment char-acteristics as the base steel, otherwise the weldedarea in the finished tool will have different hard-ness. Large compositional differences are alsoassociated with an increased cracking risk in con-

nection with hardening.Uddeholm welding consumable are designed

to be compatible with the corresponding tool steelgrades (QRO 90 WELD and QRO 90 TIG-WELDare recommended for all Uddeholm hot worksteels) irrespective of whether welding is carriedout on annealed or hardened-and-tempered basematerial.

Obviously, the weld metal of welded tools willrequire different properties for differentapplications.

For the three main application segments fortool steels (cold work, hot work and plastic mould-ing), the important weld-metal properties are:

MMA welding consumables from Uddeholm.


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Cold Work

q Hardnessq Toughnessq Wear resistance

Hot Workq Hardnessq Temper resistanceq Toughnessq Wear resistanceq Heat checking resistance

Plastic Moulding

q Hardnessq Wear resistanceq Polishabilityq Photoetchability

These properties are discussed briefly below.

HARDNESS

If the mould or die is welded in the hardenedand tempered condition, then it is important thatthe weld exhibits the same hardness as the basesteel in the as-welded condition. Such being thecase, small welds can be effected without the ne-cessity of subsequently tempering the tool. AllUddeholm welding consumables fulfil this require-ment (Fig. 3).

0 2 4 6 8 10 12 mm

0,1 0,2 0,3 0,4 0,5 inch

Heataffected

zoneBasesteel Weld metal

Tempering temperature (holding time 2 x 2h)

QRO 90WELD

55

50

45

40

35

HRC

500 550 600 650 700C

900 1000 1100 1200 1300F

Austenitizing temperature1020C (1870F)

Fig. 4. Comparison of tempering curves for QRO 90SUPREME and weld metal produced by MMA weldingwith QRO 90 WELD electrodes.

Distance from surface

HV10450

400

350

300

250

Surface

TEMPER RESISTANCE

If the mould or die is to be heat treated after weld-ing (base steel in annealed condition), then thehardening and tempering characteristics of the

weld metal should be similar to those of the basesteel so that the same hardness is obtained in both(Fig. 4).

QRO 90SUPREME

Fig. 3. Hardness profile across a weld in IMPAXSUPREME (MMA welding using IMPAX WELDelectrodes). Note the uniform hardness distribution,only marginally higher than the base hardness, and thevery narrow heat-affected zone with only a modesthardness increase at the fusion line.

TOUGHNESS

In spite of the fact that we are dealing with that isessentially a casting, weld metal in tool steel can besurprisingly tough as a result of the rather finemicrostructure derived from a high rate of solidifi-cation. In general, however, the toughness will beimproved by subsequent heat treatment. Hence,

larger weld repairs on a fully-hardened tool shouldalways be tempered after welding, even though thehardness of the weld metal and base steel may becompatible in the as-welded condition.

For cold work steels, where very high hard-ness is required, it will be advisable to use a softerfiller metal for the initial layers and finish with ahard electrode on the working surface of the tool.This procedure will produce a tougher repair thanif the hard electrode had been used throughout.

WEAR RESISTANCE

Just as with tool steel, the wear resistance of aweld metal increases with its hardness and alloycontent. Uddeholm welding consumables aredesigned to give weld metals with the same wearresistance as the compatible base steel.


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HEAT-CHECKING RESISTANCE

Welds in hot work tools will normally heat-checkfaster than the base steel because of poorer hotstrength, temper resistance or toughness (duc-

tility). However, if a consumable is used whichgives a weld metal with superior hot strength andhot hardness, then the heat-checking resistancecan be equal to or even better than the base steel.

QRO 90 WELD and TIG-WELD produce weldswhich exhibit excellent resistance to heat checking(Fig. 5).

0 100 200 300 400 500 600 C

QRO 90 WELD

STAVAX WELD/TIG WELD and IMPAX WELD/TIG WELD match theircorresponding tool steel grades exactly and give perfect results after polishingor texturing of a welded mould.

Austenitizing temperature1020C (1870F)

Holding time 2 x 1h

Fig. 5. QRO 90 WELD exhibits superior temperresistance to premium H13 base steel (ORVARSUPREME).

200 400 600 800 1000 1200F

ORVARSUPREME

HRC

60

55

50

45

40

35

30

POLISHABILITY

For plastic mould which need to be polished afterwelding, it is essential that the weld metal does notdiffer greatly in composition or hardness from the

base steel. Otherwise, an outline of the weld isvisible after polishing which will leave a witnessmark on the plastic part.

IMPAX SUPREMEand STAVAX ESRweldedwith IMPAX and STAVAX WELD (or TIG-WELD)consumables, will in conjunction with correct weld-ing procedure, normally give welds which are to allintents and purposes invisible after polishing.

PHOTOETCHABILITY (TEXTURABILITY)

The weld metal and the base steel must also besimilar in composition of a welded surface of a

plastic mould is to be textured via photoetching. Ifnot, the response to etching will vary between theweld and the base metal and this will result in awitness mark on the plastic component. Welds inIMPAX SUPREMEand STAVAX ESRwith IMPAXor STAVAX WELD (or TIG-WELD) will normallynot be discernible after photoetching, providedthat the proper welding procedure is used.


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Be careful asregards hydrogen!Weld in tool steel have high hardness and are,

therefore, especially susceptible to cold crackingderived from hydrogen ingress during welding. Inmany cases, hydrogen is generated as a result ofwater vapour being adsorbed in the hygro-scopiccoating of MMA electrodes (Fig. 6).

(Basic)

(Rutile)

Flux-cored wire (CO2)

Very low Low Medium High

0 5 10 20

Hydrogen concentration in ml/100 g of weld metal.

Fig. 6. Typical quantities of hydrogen available andweldmetal hydrogen contents for different welding

processes and electrode types.

The susceptibility of a weld to hydrogencracking depends on:

q The microstructure of the weld metal (differentmicrostructures have different hydrogensensitivities)

q The hardness of the steel (the greater thehardness, the higher the susceptibility)

q The stress levelq The amount of diffusible hydrogen introduced

in welding.

MICROSTRUCTURE/HARDNESS

The characteristic microstructures giving highhardness in the heat-affected zone and weld metal,i.e. martensite and bainite, are particularly sensi-tive to embrittlement by hydrogen. This suscepti-bility is, albeit only marginally, alleviated bytempering.

Amountofhy

dro

genavailable

STRESS LEVEL

Stresses in welds arise from three sources:

Contraction during solidification of the moltenpool

Temperature differences between weld, heat-affected zone and base steel

Transformation stresses when the weld andheat-affected zone harden during cooling.

In general, the stress level in the vicinity of theweld will reach the magnitude of the yield stress,which for hardened tool steel is very high indeed.It is very difficult to do anything about this but thesituation can be improved somewhat via properweld design, (bead location and sequence of runs).However, no measures to reduce stress will help ifthe weld is seriously contaminated by hydrogen.

CONTENT OF DIFFUSIBLE HYDROGEN

As regards the susceptibility of welds to cold crack-ing, this is the factor that it is easiest to do some-thing about. By adhering to a number of simpleprecautions, the amount of hydrogen introducedduring welding can be reduced appreciably. Always store coated electrodes in a heated stor-

age cabinet or heated container once the packhas been opened (see earlier).

Contamination on the surfaces of the joint of thesurrounding tool surface, e.g. oil, rust or paint,

is a source of hydrogen. Hence, the surfaces ofthe joint and of the tool in the vicinity of the jointshould be ground to bare metal immediatelyprior to starting to weld.

If preheating is performed with a propaneburner, it should be remembered that this cancause moisture to form on the tool surfaces notdirectly impinged by the flame.

Coated

electrod

es

Gas

metal

arc


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Weld metal

HV10

600

500

400

0 1 2 3 4 5 6 7 8 mm

Fusion line

Preheating in an insulated box.

It will be clear from this discussion that theentire welding operation should be completedwhile the tool is hot. Partially welding, letting thetool cool down and then preheating later on tofinish the job is not to be recommended because

there is considerable risk that the tool will crack.While it is feasible to preheat tools in a fur-

nace, there is the possibility that the temperatureis uneven (creates stresses) and that it will dropexcessively before welding is completed (espe-cially if the tool is small).

The best method of preheating and maintain-ing the tool at the requisite temperature duringwelding is to use an insulated box with electricalelements in the walls (see earlier).

Fig. 7 shows the differences in hardnessdistribution across welds which were made on

tools preheated in a furnace and in an insulatedbox. It is clear that the tool preheated in a furnaceshows a considerably greater scatter in hardnessthan that preheated in an insulated box.

Parentmetal(460)

0 0,1 0,2 0,3 inch

Elevated workingtemperatureThe basic reason for welding tool steel at elevated

temperature derives from the high hardenabilityand therefore crack sensitivity of tool steel weldsand heat-affected zones. Welding of a cold tool willcause rapid cooling of the weld metal and heat-affected zone between passes with resulting trans-formation to brittle martensite and risk for crack-ing. Cracks formed in the weld could well propa-gate through the entire tool if this is cold. Hence,the mould or die should during welding be main-tained at 50100C (90180F) above the Ms-tem-perature (martensite-start temperature) for thesteel in question; note that, strictly speaking, the

critical temperature is the Ms of the weld metal,which may not be the same as that of the basemetal.

In some instances, it may be that the base steelis fully hardened and has been tempered at a tem-perature below the Ms-temperature. Hence, pre-heating the tool for welding will cause a drop inhardness. For example, most low-temperaturetempered cold-work steels will have to be pre-heated to a temperature in excess of the temperingtemperature, which is usually ca. 200C (400F).The hardness drop must be accepted in order toperform a proper preheating and mitigate the riskfor cracking during welding.

During multi-run welding of a properly pre-heated tool, most of the weld will remain austeniticunder the entire welding operation and will trans-form slowly as the tool cools down. This ensures auniform hardness and microstructure over thewhole weld in comparison with the situation whereeach run transforms to martensite in betweenpasses (quite apart from the risk for cracking inthe latter instance).

Preheating temperature 350C (660F) infurnace

Preheating temperature 350C (660F) ininsulated box

Fig. 7. Hardness distribution across welds usingQRO 90 WELD where preheating has been performedin a furnace and in an insulated box.


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BUILDING UP THE WELD

First of all, the joint surfaces are clad in using anappropriate number of runs. This initial layershould be made with a small diameter MMA elec-

trode (3,25 mm 1/8 inch max.) or via TIGwelding (max. current 120 A).

The second layer is made with the same elec-trode diameter and current as the first in order thatthe heat-affected zone is not too extensive. Theidea here is that any hard, brittle microstructures,which may form in the base-material heat-affectedzone of the first layer, will be tempered by the heatfrom the second layer and the propensity to crack-ing will thereby be reduced. The remainder of thejoint bode can be welded with a higher current andlarger-diameter electrodes.

The final runs should be built up well abovethe surface of the tool. Even small welds shouldcomprise a minimum of two runs. Grind off the lastruns.

During welding, the arc should be short andthe beads deposited in distinct runs. The electrodeshould be angled at 90 to the joint sides so as tominimize undercut. In addition, the electrodeshould be held at an angle of 7580C to the direc-tion of forward movement.

3.Filling up

2.Second layer

1.Initial cladding

Welding procedureEven with the very best of equipment and properlydesigned consumables, tool steel can not bewelded successfully unless considerable care isexercised injoint preparation, in the actualweld-ing operation, and i performing properheattreatment after welding.

JOINT PREPARATION

The importance of careful joint preparation can notbe over-emphasized. Cracks should be ground outso that the joint slope at an angle of at least 30 tothe vertical. The width of the joint bottom shouldbe at least 1 mm (0.04 inch) greater than the maxi-mum electrode diameter which will be used.

Erosion or heat-checking damage on hot worktools should be ground down to sound steel.

The tool surfaces in the immediate vicinity ofthe intended weld and the surfaces of the jointitself must all be ground down to clean metal. Priorto starting welding, the ground areas should bechecked with penetrant to make sure all defectshave been removed. The tool should be weldedimmediately joint preparation is finished, becauseotherwise there is risk for contamination of thejoint surfaces with dust, dirt or moisture.

Pa ss sequ en ce

$

J o in t pr epa r a t i on

R igh t !

Wrong!

$


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The completed weld(s) should be carefullycleaned and inspected prior to allowing the tool tocool down. Any defect, such as arcing sores orundercut, should be dealt with immediately. Be-fore the tool has cooled, the surface of the weld

should be ground down almost to the level of thesurrounding tool before any further processing.

Moulds where welded areas have to bepolished or photo-etched should have the finalruns made using TIG-welding, which is less likelyto give pores or inclusions in the weld metal.

HEAT TREATMENT AFTER WELDING

Depending on the initial condition of the tool,the following heat treatments may be performedfollowing welding:

Tempering

Soft annealing, then hardening + tempering asusual

Stress relieving.

Tempering

Fully-hardened tools which are repair weldedshould if possible be tempered after welding.

Tempering improves the toughness of theweld metal and is particularly important when thewelded area is highly stressed in service (e.g. coldwork and hot work tooling).

The tempering temperature should be chosenthat the hardness of weld metal and base steel arecompatible. An exception to this rule is when theweld metal exhibits appreciably improved temperresistance over the base material (e.g. ORVARSUPREMEwelded with QRO 90 WELD); in thiscase, the weld should be tempered at the highestpossible temperature concomitant with the basesteel retaining its hardness (typically 20C/40Funder the previous tempering temperature).

Product brochures for Uddeholm weldingconsumables and tool steels give tempering curvesfrom which the tempering conditions for welded

tools can be ascertained.Very small repairs need not be tempered after

welding; however, this should be done if at allpossible.

Electrode

Workpiece

Fig. 8. A copper plate as support for the weld whenbuilding up corners.

vv

The arc should be struck in the joint and noton any tool surfaces which are not being welded.The sore form striking the arc is likely location forcrack initiation. In order to avoid pores, the start-ing sore should be melted up completely at the

beginning of welding. If a restart is made with apartly-used MMA electrode, the tip should becleaned free from slag; this assists striking the arcat the same time as a potential source of porosity iseliminated.

In building up edges or corners, both time andconsumables can be saved by using a piece ofcopper plate or graphite as support for the weldmetal (Fig. 8). Using such support also means thatthe molten pool i hotter which reduces the risk forpore formation (low currents need to be usedwhen building up sharp edges or corners).

If copper or graphite support is used, an extra1,5 mm (0,06 inch) must be allowed between thesupport and the required weld surface because theslag takes up a certain amount of space (MMAwelding).

For repair or adjustment of expensive tooling,e.g. plastic mould with a polished or texturedcavity, it is essential that there is good contactbetween the return cable and the tool. Poor contactgives problems with secondary arcing and theexpensive surface can be damaged by arcingsores. Such tools should be placed on a copperplate which provides for the best possible contact.The copper plate must be preheated along with thetool.

Space for slag Copper-plate


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Soft annealing

Tools which are welded to accommodate designchanges or machining errors during toolmaking,and which are in soft-annealed condition, will needto be heat treated after welding. Since the weld

metal will have hardened during cooling followingwelding, it is highly desirable to soft anneal theweld prior to hardening and tempering of the tool.The soft annealing cycle used is that recommend-ed for the base steel. Thewelded area can then bemachined and the tool may be finished and heattreated as usual. However, even if the tool can befinished by merely grinding the weld, soft anneal-ing is first recommended in order to mitigatecracking during heat treatment.

Stress relieving

Stress relieving is sometimes carried out afterwelding in order to reduce residual stresses. Forvery large or highly-constrained welds, this is animportant precaution. If the weld is to be temperedor soft annealed, then stress relieving is not nor-mally necessary. However, pre-hardened tool steel,e.g.IMPAX SUPREMEwelded with IMPAXWELD or IMPAX TIG-WELD, should be stressrelieved after welding since no other heat treat-ment is normally performed.

The stress relieving temperature must be cho-sen such that neither the base steel nor the weldedarea soften extensively during the operation. If

IMPAX SUPREME is to be machined after weld-ing, it is absolutely essential that the mould isstress relieved in order that adequate dimensional

stability is achieved.Very small weld repairs or adjustments will

normally not require a stress relieving treatment.

Heat treatment of a die-casting die after welding.


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Softannealing

Softannealing

Softannealing

None

Tempering

Tempering

Tempering


UddeholmTool Steel

VIDARSUPREME

ORVARSUPREME/ORVAR2Microdized

QRO 90

SUPREME

ALVAR 14

VIDARSUPREME

ORVARSUPREME/ORVAR 2Microdized

QRO 90SUPREME

Condition

Soft annealed

Soft annealed

Soft annealed

Prehardened

Hardened

Hardened

Hardened

Weldingmethod

TIG

TIG

TIG

TIG

TIG

TIG

TIG

Consumables

QRO 90 TIG-WELD

QRO 90 TIG-WELD

QRO 90 TIG-WELD

UTPA 73G4ESAB OK

Tigrod 13.22

QRO 90 TIG-WELD

QRO 90 TIG-WELD

QRO 90 TIG-WELD

Hardnessas welded

5055 HRC

5055 HRC

5055 HRC

340390 HB340390 HB

5055 HRC

5055 HRC

5055 HRC

Preheatingtemperature

Min. 325C(620F)

Min. 325C(620F)

Min. 325C

(620F)

225275C(430520F)

Min. 325C(620F)

Min. 325C(620F)

Min. 325C(620F)

Softannealing

Softannealing

Soft

annealing

None

Tempering

Tempering

Tempering

UddeholmTool Steel

VIDARSUPREME


QRO90SUPREME

ALVAR 14

VIDARSUPREME


QRO90SUPREME

Condition

Soft annealed

Soft annealed

Soft annealed

Prehardened

Hardened

Hardened

Hardened

Consumables

QRO 90 WELD

QRO 90 WELD

QRO 90 WELD

UTP 73G4

ESAB OK 83.28

QRO 90 WELD

QRO 90 WELD

QRO 90 WELD


Min. 325C(620F)

Min. 325C(620F)

Min. 325C(620F)

225275C

(430520F)

Min. 325C(620F)

Min. 325C(620F)

Min. 325C(620F)

Weldingmethod

MMA(SMAW)

MMA(SMAW)

MMA(SMAW)

MMA

(SMAW)

MMA(SMAW)

MMA(SMAW)

MMA(SMAW)

The following tables give details concerning weld repair or adjustment of tooling made fromUddeholm tool steel grades for hot work, plastic moulding and cold work applications.

Hardnessas welded

5055 HRC

5055 HRC

5055 HRC

340390 HB

340390 HB

5055 HRC

5055 HRC

5055 HRC

Heattreatment

WELD REPAIR OF HOT WORK TOOL STEEL

Heattreatment

Remarks

Heat treatment.See data sheetfor parent steel.

Stress relieve

large repairs.

1020C(2040F)below theoriginal temperingtemperature.

Remarks

Heat treatment.See data sheetfor parent steel.

Stress relievelarge repairs.

1020C(2040F)below theoriginal temperingtemperature.


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15

Remarks

Heat treatment.See data sheet forparent steel.

Tempering temp.200250C(390480F)

Stress relieve large

repairs.



Stress relieve largerepairs.

Welding of ELMAXshould generally beavoided, due to therisk for cracking.

See Uddeholmbrochure.

Contact nearestUddeholm office.

UddeholmTool Steel

STAVAXESR

STAVAXESR

IMPAX

SUPREME

GRANE

RAMAX S

HOLDAX

ELMAX

CALMAX

CALMAX

UddeholmTool Steel

STAVAX

ESR

STAVAXESR

IMPAXSUPREME

GRANE

RAMAX S

HOLDAX

ELMAX

CALMAX

CALMAX

Consumables

STAVAX TIG-WELD

STAVAX TIG-WELD

IMPAX TIG-WELD

UTPA 73G2UTPA 67S

STAVAX TIG-WELD

IMPAX TIG-WELD

UTPA 701

CALMAX/CARMO TIG-WELD

CALMAX/CARMO TIG-WELD

Condition

Softannealed

Hardened

Prehardened

Hardened

Prehardened

Prehardened

Hardened

Softannealed

Hardened

Weldingmethod

TIG

TIG

TIG

TIG

TIG

TIG

TIG

TIG

TIG


200250C(390480F)

200250C(390480F)

200250C

(390480F)

225275C(430520F)

200250C(390480F)

150200C(300390F)

250300C(480570F)

200250C(390480F)

180250C(360480F)

WELD REPAIR OF PLASTIC MOULD STEEL

Remarks

Heat treatment.

See data sheet forparent steel.






Welding of ELMAXshould generally beavoided, due to therisk for cracking.

See Uddeholmbrochure.

Contact nearestUddeholm office.

Consumables

STAVAX WELD

STAVAX WELD

IMPAX WELD

UTP 73G2UTP 67S

STAVAX WELD

IMPAX WELD

Inconel 625 typeUTP 701

CALMAX/CARMO WELD

CALMAX/CARMO WELD

Weldingmethod

MMA

(SMAW)

MMA(SMAW)

MMA(SMAW)

MMA(SMAW)

MMA(SMAW)

MMA(SMAW)

MMA(SMAW)

MMA(SMAW)

MMA(SMAW)

Condition

Soft annealed

Hardened

Prehardened

Hardened

Prehardened

Prehardened

Hardened

Softannealed

Hardened


200250C

(390480F)

200250C(390480F)

200250C(390480F)

225275C(430520F)

200250C(390480F)

150200C(300390F)

250300C(480570F)

200250C(390480F)

180250C(360480F)

Heattreatment

Soft

annealing

Tempering

None

Tempering

Tempering

None

Tempering at200C(390F)

Softannealing

Tempering

Heattreatment

Softannealing

Tempering

None

Tempering

Tempering

None

Tempering at200C(390F)

Softannealing

Tempering

Hardnessas welded

5456 HRC

5456 HRC

320350 HB

5558 HRC

5456 HRC

320350 HB

~ 56 HRC

5861 HRC

5861 HRC

Hardnessas welded

5456 HRC

5456 HRC

320350 HB

5558 HRC

5456 HRC

320350 HB

280 HBca. 56 HRC(initial plus

finishing layersrespectively)

5962 HRC

5962 HRC


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16

Hardnessas welded

300 HB

5558 HRC

5356 HRC

6064 HRC

280 HB

5356 HRC

5558 HRC

6064 HRC

6064 HRC

280 HB5356 HRC

6064 HRC

6064 HRC

5861 HRC


200250C(390480F)

200250C(390480F)

200250C(390480F)

200250C(390480F)

200250C(390480F)

200250C(390480F)

200250C(390480F)

200250C(390480F)

UddeholmTool Steel

ARNE

FERMO

RIGOR

VIKING

SVERKER 21

SVERKER 3

VANADIS 4

CARMO

CALMAX

UddeholmTool Steel

ARNE

FERMO

RIGOR

VIKING

SVERKER 21

SVERKER 3

VANADIS 4

CARMO

CALMAX


WELD REPAIR OF COLD WORK TOOL STEEL

Condition

Hardened

Prehardened

Hardened

Hardened

Hardened

Hardened

Hardened

Prehardened

ConsumablesWeldingmethod

TIG

TIG

TIG

TIG

TIG

TIG

TIG

TIG

TIG

ConsumablesCondition

Hardened

Prehardened

Hardened

Hardened

Hardened

Hardened

Hardened

Prehardened

Weldingmethod

MMA

(SMAW)

MMA(SMAW)

MMA(SMAW)

MMA(SMAW)

MMA(SMAW)

MMA(SMAW)

MMA(SMAW)

MMA(SMAW)

MMA(SMAW)

AWS E312

ESAB OK 84.52

UTP 67S

Castolin 2

Castolin N 102

Inconel 625 type

UTP 67S

Castolin 2

Castolin 6

Inconel 625 typeCastolin 6

CALMAX/CARMOWELD


200250C

(390480F)

200250C(390480F)

200250C(390480F)

200250C(390480F)

200250C(390480F)

200250C(390480F)

200250C(390480F)

200250C(390480F)

AWS ER 312

UTPA 67S

UTPA 73G2

Castotig 5

Inconel 625 type

UTPA 73G2

UTPA 67S

UTPA 696

Castotig 5

Inconel 625 typeUTPA 73G2UTPA 696Castotig 5

CALMAX/CARMOTIG-WELD

See Weld repair of plastic mould steel

See Weld repair of plastic mould steel

N.B. Consumables with high carbon content are generally not recommended for MMA welding because of the cracking risk.

Hardnessas welded

300 HB

5354 HRC

5558 HRC

5460 HRC

5460 HRC

280 HB

5558 HRC

5660 HRC

5961 HRC

280 HB5961 HRC

5962 HRC

Remarks

Initial layers welded with soft weldmetal.

Choose consumable for finishinglayers which gives suitablehardness.

For FERMO and CARMO, smallrepairs can be made with tool atambient temperature.

Initial layers welded with soft weldmetal.

Choose consumable for finishinglayers which gives suitablehardness.

For FERMO and CARMO, smallrepairs can be made with tool atambient temperature.

Castotig 5 should not be used formore than 4 layers (cracking risk).

Remarks


17/17


Further informationInformation concerning heat treatment of the tool subsequentto welding can be obtained from the brochures for the welding

consumable and/or the tool steel in question.

Documents

Welding of Tool Steel - Uddeholm (eBook, 17 Pages)