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High Carbon Chrominum Cold Work Tool Steels

Advanced TIP TIG Welding
TIP TIG Welding is always better quality than TIG and 100 to 500% faster with superior quality than TIG - MIG - FCAW.

 
 
   




Written by Ed Craig
www.weldreality.com>



As site changes are frequent, please refresh before using.





(D) STEELS. HIGH CARBON - CHROMINUM,
COLD WORK TOOL STEELS.

 

(D) Steels. AISI / SAE D2 / D3 / D4 / D5 / D6 / D7
UNS T3040X - ASTM A681

(D) Steels. Air or oil hardened. Hardness 54 - 61 HRC (D7 to 66 HRC)

(D) Steels. Carbon 1.4 - 2.5% / Chrome 11-13.5% / Mo 1% / V 1.4 -4%

(D) Steels. About 50% machinability of (W) steels annealed.
W steels = 100% machinability.

(D) Steels. Unmachinable when hardened.

(D) Steels. Grinding can cause expansion and cracking.

(D) Steels. None deforming yet highly stressed and low impacts.

(D) Steels subject to thermal cracking near stress raisers.

(D) Steels Annealing temperature 1650F

(D) Steels Hardened in air temp 1850F

(D) Steels Tempering temp 900F, hold temper minimum
3-4 hrs after welding..

(D) Steels weld pre-post heat 900F

(D) Steels Interpass max temp 800F



D2
Germany - Din 1.2379
UK - BD2
Carbon 1.6% max.
Mn 0.6 / Si0.6 / Cr13 / Ni 0.3
Mo1.2 / Co 1 / V 1.1.
D3France - Z200 C 12
UK - BD3
Germany - DIN 1.2080
Japan - SKD 1

 

What is Brittleness?:The ease at which the weld or metal will break or crack without appreciable deformation. When a metal gets harder it becomes more brittle. Preheat, inter-pass temp controls and post heat all are designed to reduce the potential for brittleness.




GENERAL CONSIDERATIONS FOR WELDING TOOL STEELS:

Ensure base metals are clean avoid tool marks.

Remove all sharp edges and tight corners in weld areas.

Use Dye pen to check for surface cracks.

Majority of tool steels will be weld repaired in the Hardened condition

A hardness test will determine if steel is hard or annealed.

To weld massive tool parts with large amounts of weld "anneal first"

Steels in the annealed condition metal can be removed with an oxy acet/fuel torch.

Steels in the hardened condition use grinding/carbon arc rather than oxy fuel or plasma to remove metal.

Discoloration glazing of steel while grinding indicates damage.


Preheating before grinding or oxy cutting prevents damage.




ALL TOOL STEELS MUST BE PRE HEATED BEFORE WELDING.

Pre heat prevents cracking, distortion stresses and shrinking.

Annealed or hardened steels the steel must be pre heated.

If base metal hardened yet not tempered anneal temper first.

Preheat hardened steels don't exceed temper temperature.

Hardened steels if temper unknown >25mm use 300 to 400F preheat.

Annealed steels, preheat at maximum pre heat recommendation.

If steels are quenched and tempered to match tool steel properties, the
electrode selection and heat treatment recommendations critical.


What is Hardness? The resistance of the metal or the weld to penetration. Hardness is related to the strength of the metal. A good way to test the effectiveness of the weld procedure after the weld and heat treatment is complete, test the hardness of weld and the base metal surrounding the weld.



WELDING TOOL STEELS:

With all tool steels the first weld consideration should be does the weld require the same hardness as the base.

Is the metal to be welded in the annealed or hardened condition.

Use lowest possible weld current, (smallest electrode diamaeter)

No weaves use stringer beads.

Peen each weld after completion,

Ensure parts are clean.

Avoid excess joint restraints.


What is Ductility? The amount that a metal or weld will deform without breaking. Measured on welds by the % of elongation in a 2 inch 51 mm test piece. An E71T-1 flux cored electrode should result in a minimum of 20% elongation. An E70S--6 MIG weld should produce approx 22%.

TOOL STEELS AND SMAW ELECTRODE DATA.

SMAW Electrodes most versatile weld process for tool steels.

Electrode 3/32 2.5mm amperage 50 to 80 amps DCSP

Electrode 1/8 3.2.5mm amperage 70 to 115 amps DCSP

Electrode 5/32 4mm amperage 100 to 150 amps DCSP

Most tool and die SMAW electrodes use AC-DC Positive.

Flux cored good for welds which benefit from high weld depositions.

GTAW, TIG good for small precise welds.

  • Don't use oxy fuel to weld.
  • Ask. Is the weld for joining or does the weld require a
    specific mechanical property ( hardness or machinability)?
  • Use smallest electrodes possible.
  • Peen each weld bead.
  • Avoid arc strikes.
  • Consider run on plates.
  • Avoid craters.
  • Try to use stringers rather than weaves.
  • If possible for the firsts pass (butter pass) consider the E312 electrode except for water hardened steels.
  • For water hardened steels use E11018 instead of E312 for butter pass.
  • When using E312 use only one layer to avoid shrink cracks.
  • If excessive hardness not required in weld use E312 then an E9018-6 or E11018-

    FOR LARGE COMPONENTS THAT REQUIRE BOTH STRENGTH AND HARDNESS

    • First use E312 followed by E11018-G followed by the tool steel.
    • Try to provide a minimum of 3 layers of tool steel weld to a minimum depth of 3mm.
    • If the repairs are on annealed steels remember the electrode selected must respond to heat treatment after weld.
    • The weld hardness will depend on the preheat/interpass temperatures plus weld procedures.
    • The weld hardness will depend on the chemistry of the selected electrode along with the base metal dilution.
    • The weld hardness will depend on the post heat treatment and cooling rate time.
    • To join components, and prevent cracks preheat and deposit ductile electrodes.
    • To prevent cracks, limit carbon pickup in first pass, (use low current narrow stringer beads) also if possible stress relieve.
    • To minimize the potential for underbead cracks, preheat and limit heat input during the
      weld.
    • To prevent underbead cracks provide uniform cooling, with immediate stress relief.
    • Fast heating or concentrated heating can cause cracks.


    What is Toughness:
    The ability of the metal or weld sample at a predetermined temperature to withstand a shock.The test for toughness measures the impact of a pendulum
    on a notched specimen. You may see that the required impact properties for the metal or weld are 20ft-lbf @ -20 F (27 j @ -29C)
    reheat at maximum pre heat recommendation.


    TOOL STEELS, PRE HEAT BASICS

    M-T-H-D2 Pre heat 900F (482C)

    • All other tool steels preheat at 350F (176C)
    • Preheat "slowly" The higher the alloy content the slower the preheat.
    • Preheat, the more complex the part shape the slower the preheat.
    • Preheat. High alloy steels avoid oxy fuel use ovens or electric.
    • Preheat. Use insulation around part to retain heat.
    • Preheat. Maintain preheat during welds, don't exceed preheat temp.

     

The "yield and tensile strength". The stress that can be applied to a base metal or weld without "permanent deformation" of the metal. The "tensile strength". The ultimate tensile strength, the maximum tensile strength that the metal or weld can with stand before "failure



TOOL STEELS AND PRACTICES TO AVOID CRACKING.

Annealed steels preheat, for the weld stress relieve, machine harden temper.

Hardened steels, pre heat, weld temper then grind finish.

 

DECARBURIZATION = LOSS OF CARBON CAUSES SURFACE SOFTENING.

Coating surface with Borax prevents decarburization.


TEMPERING
FOLLOW AFTER QUENCHING TO REDUCE HARDENING STRESSES.

High temper provides more toughness with less hardness.

Tempering at low end provides max hardness (max wear) with less toughness.

Tempering above Temper range reduces toughness.

For large repairs on hardened steels use the electrode temper requirements.

Welding on hardened steels not tempered cracking will occur.




    Brittleness: The ease at which the weld or metal will break or crack without appreciable deformation. When a metal gets harder it becomes more brittle. Preheat, inter-pass temp controls and post heat all are designed to reduce the potential for brittleness.




    STRESS RELIEVING (SR) BASIC GUIDELINES:
    • STRESS RELIEF - CONTROLLED HEATING & COOLING TO REDUCE STRESS.
    • STRESS RELIEF MACHINED PARTS FOR DIMENSIONAL STABILITY.
    • STRESS RELIEF SLOW HEATING AND COOLING REQUIRED
    • CONFIRM WITH CODE SPECIFICAIONS FOR STRESS RELIEF REQUIREMENTS.

     

    Fatigue: The ability of a metal or weld to withstand repeated loads. Fatigue failures occur at stress levels less than the metal or weld yield strength. Some things that can influence fatigue failure:

    • Excess weld profiles.
    • Welds with undercut.
    • FCAW or SMAW slag inclusions.
    • Lack of weld penetration.
    • Excess weld heat, typically from multi-pass welds without inter-pass temp controls.
    • Items to a part that adds restraint while welding.
    • Items added to a part that can concentrate stresses in a specific location.
    • Incorrect selection of filler metal, weld too weak or weld too strong.

       

        STRESS RELIEVING

      TYPICAL STRESS RELIEF SOAK TIME
      ONE HOUR PER INCH OF THICKNESS

      SR HEAT & COOL RATE PER HOUR 400oF 204oC DIVIDE THICKER PART
      PARTS OF DIFFERENT THICKNESSES
      SR MAX TEMP DIFFERENCE 75oF 24oC
      STRESS RELIEF CARBON STEELS 1100oF 593oC
      TO 1250oF 677oC
      STRESS RELIEF CARBON 0.5% Mo
      1100oF 593oC TO 1250oF 677oC
      SR 1% CHROME 0.5% Mo
      1150oF 621oC TO 1325oF 718oC
      SR 1.25 % CHROME 0.5% Mo
      1150oF 621oC TO 1325oF 718oC
      SR 2% CHROME 0.5% Mo
      1150oF 621oC TO 1325oF 718oC
      SR 2.25 % CHROME 1% Mo
      1200oF 649oC TO 1375oF 746oC
      SR 5% CHROME 0.5% Mo
      1200oF 649oC TO 1375oF 746oC
      SR 7% CHROME 0.5% Mo
      1300oF 704oC TO 1400oF 760oC
      SR 9% CHROME 1% Mo
      1300oF 704oC TO 1400oF 760oC
      SR 12% CHROME 410 STEEL
      1550oF 843oC TO 1600oF 871oC
      SR 16% CHROME 430 STEEL
      1400oF 760oC TO 1500oF 815oC
      SR 9% NICKEL
      1025oF 552oC TO 1085oF 585oC
      FOR 300 SERIES STAINLESS SR WILL
      RESULT IN CARBIDE PRECIPITATION
      WITH LOW CARBON 300 SERIES
      MAX SR 1050oF 566oC
      SR 400 SERIES CLAD STAINLESS
      1100oF 593oC TO 1350oF 732oC
      SR CLAD MONEL INCONEL Cu NICKEL
      1150oF 621oC TO 1200oF 649oC
      STRESS RELIEF MAGNESIUM AZ31B 0
      500oF 260oC 15 MIN
      STRESS RELIEF MAGNESIUM AZ31B
      H24 300oF 149oC 60 MIN

      HK31A H24 550oF 288oC 30 MIN

      HM21A T8-T81 700oF 371oC 30 MIN

      MAGNESIUM WITH MORE THAN 1.5%
      ALUMINUM STRESS RELIEF
      MAGNESIUM CAST ALLOYS AM100A
      500oF 260oC 60 MIN
      AZ-63A 81A 91C & 92A
      500oF 260oC 60 MIN
       
        
       


      If steels are quenched and tempered to match properties electrode
      selection and heat treatment recommendations critical.



      HARDNESS CONVERSION FOR CARBON AND LOW ALLOY STEELS.
      1000 psi = ksi x 6.894 = MPa

      Steel 0.15 Carbon Tensile 60- 65 ksi 413 448 MPa
      Hardness Br 132

      HRC 43 Br 400 Tensile 201 ksi 1385 MPa
      HRC 44 Br 409 Tensile 208 ksi 1434 MPa
      Steel 0.3 Carbon Tensile 85 ksi 568 MPa
      Hardness Br 172
      HRC 45 Br 421 Tensile 215 ksi 1482 MPa
      HRC 46 Br 432 Tensile 222 ksi 1530 MPa
      Steel 0.5 Carbon Tensile 100 ksi 689 MPa
      Hardness Br 219
      HRC 47 Br 443 Tensile 229 ksi 1578 MPa
      HRC 48 Br 455 Tensile 237 ksi 1634 MPa
      HRC 20 Br 228 Tensile 111 ksi 765 MPa
      HRC 21 Br 233 Tensile 113 ksi 779 MPa
      HRC 50 Br 481 Tensile 255 ksi 1758 MPa
      HRC 52 Br 512 Tensile 273 ksi 1882 MPa
      HRC 23 Br 243 Tensile 117 ksi 806 MPa
      HRC 24 Br 247 Tensile 120 ksi 827 MPa
      HRC 54 Br 543 Tensile 292 ksi 2013 MPa
      HRC 56 Br 577 Tensile 313 ksi 2158 MPa
      HRC 25 Br 253 Tensile 122 ksi 841 MPa
      HRC 26 Br 258 Tensile 125 ksi 861 MPa
      HRC 58 Br 615
      HRC 27 Br 264 Tensile 128 ksi 882 MPa
      HRC 28 Br 271 Tensile 132 ksi 910 MPa
      HRC 29 Br 279 Tensile 132 ksi 910 MPa
      HRC 30 Br 286 Tensile 138 ksi 951 MPa
      HRC 31 Br 294 Tensile 142 ksi 979 MPa
      HRC 32 Br 301 Tensile 145 ksi 999 MPa
      HRC 33 Br 311 Tensile 149 ksi 1027 MPa
      HRC 34 Br 319 Tensile 153 ksi 1054 MPa
      HRC 35 Br 327 Tensile 157 ksi 1082 MPa
      HRC 36 Br 336 Tensile 162 ksi 1116 MPa

       

      HRC 37 Br 344 Tensile 167 ksi 1151 MPa
      HRC 38 Br 353 Tensile 171 ksi 1179 MPa
      HRC 39 Br 362 Tensile 176 ksi 1213 MPa
      HRC 40 Br 371 Tensile 181 ksi 1247 MPa
       
      HRC 41 Br 381 Tensile 188 ksi 1296 MPa
      HRC 42 Br 390 Tensile 194 ksi 1337 MPa
       

       

       


      • DECARBURIZATION = LOSS OF CARBON CAUSES SURFACE SOFTENING.
      • Coating surface with Borax prevents decarburization.

      • ANNEAL HEAT ABOVE CRITICAL TEMP THEN COOL 50F (10C) PER HR TO TEMPER.

      • STRESS RELIEVE BELOW CRITICAL TEMP. TYPICAL 1100-1300F (700C) WITH SLOW COOL. Don't stress relieve a weld on hardened steel.

      • TEMPERING FOLLOW AFTER QUENCHING TO REDUCE HARDENING STRESSES.
      • High temper provides more toughness with less hardness.
      • Tempering at low end provides max hardness (max wear) with less toughness.
      • Tempering above Temper range reduces toughness.
      • With hardened steel let steel cool to 150F (65c) then temper.
      • For large repairs on hardened steels use the electrode temper requirements.
      • Welding on hardened steels not tempered cracking will occur.