PM M-4

PM M-4 is a high-vanadium special purpose high speed steel exhibiting better wear resistance and toughness than M2 and M3 in cold work punches, die inserts and cutting applications involving high speed and light cuts.

Chemical Composition:

  • Carbon 1.40%
  • Manganese 0.30%
  • Sulfur 0.06%
  • Molybdenum 5.25%
  • Vanadium 4.00%
  • Silicon 0.55%
  • Chromium 4.00%
  • Tugnsten 5.50%

Typical Applications:

  • Powder Compaction Punches
  • Gear Hobs
  • Shaper Cutters
  • Broaches
  • Milling Cutters
  • Rolls
  • Punches

Thermal Treatments

Preheat:

1500/1550F (820/845C), equalize, Second preheating stage at 1800/1850F (1010/1040C) recommended for vacuum or atmosphere hardening. Equalize.

Austenize:

1850/2150F (1010/1175C), 30/45 minutes at temperature. Standard recommendation to achieve RC 60-62 after tempering is to use 2050F (1120C)

Quench:

Salt, oil or atmosphere quench to 1000-1100F(540-595C), equalize, then air cool to below 125F(50C) or hand warm. Vacuum or atmosphere quench rate through 1850-1300F (1010-705C) range is critical to achieve optimum heat treat results.

Temper:

1000F (540C) minimum, hold 2 hours at temperature, air cool. Temper twice minimum. Triple tempering is recommended if austenizing at 2000F (1095C)

Cryogenic Treating:

Refrigeration treatments may improve long term dimensional stability by transforming retained austenite. Refrigeration treatments should generally be performed after the first temper, and must be followed by a temper.

Hardening Data

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Temperature   1850F 1900F 1950F 2050F 2100F 2150F
°C °F (1025C) (1040C) (1065C) (1120C) (1150C) (1175C)
As Quenched   61 63 65 65 64.5 63.5
540 1000 56 57 60.5 62 63 64
550 1025 54 56 58.5 60 62 63
565 1050 52 54 56.5 58 60 61
595 1100 49 51 52 54 55 56
620 1150 44 45 46 48 50 51
650 1200 40 41 43 46 47 48



Surface Treatments

PM M-4 can be nitrided, steam tempered or titanium-nitride coated if desired. If the CVD TiN treatment is used, care is required in vacuum hardening.

Annealing

Heat to 1600F (870C), hold 2 hours, slow cool 30F (15C)/hour maximum) to 1000F (540C), then furnace or air cool.
Typical annealed hardness: 225/255 BHN.

Stress Relieving

Annealed Material: Heat to 1100/1300F (595/740C), hold two hours, cool in still air.
Hardened Material: Heat to 25F (15C) below original tempering temperature, hold two hours, cool in still air.

Welding

Welding of PM M-4 is generally not recommended due to the fine-grain microstructure produced by the PM process. If weld repair must be performed, use air hardening tool steel filler material.
Annealed Material: Preheat 1000/1100F (540/595C), maintain over 1000F (540C) during welding. Reanneal or temper 1550F (845C) 6 hours after welding.
Hardened Material: Preheat to 25F (15C) below original tempering temperature (1000F (540C) minimum). Maintain above 900F (480C) during welding. Cool to 150F (65C) after welding. Temper 25F (15C) below original tempering temperature. Minimum 1000F (540C)

Physical Properties

  • Modulus of Elasticity,31psix10(6):(221 GPa)
  • Density:0.288 lb./in3 (7972 kg/M3)
  • Thermal Conductivity:12.1 BTU/hr./ft./F( 21 W/m/ °K)