High Speed Steel
M2
M-2 High Speed Steel Data Sheet
M-2 is a general purpose molybdenum-type high speed steel exhibiting well-balanced toughness, wear resistance and red hardness properties. This grade is commonly used in cold work punches and dies and cutting applications involving high speed and light cuts.
Chemical Composition
Carbon | 0.85% |
Manganese | 0.28% |
Chromium | 4.15% |
Molybdenum | 5.00% |
Vanadium | 1.85% |
Tungsten | 6.15% |
Silicon | 0.30% |
Typical Applications
Broaches | Milling Cutters |
Drill Bits | Pins |
Reamers | Punches |
Powder Compaction Pins |
Thermal Treatments
Preheat : 1450/1500F (820/845C), equalize, Second preheating stage at 1850/1900F (1010/1040C)recommended for vacuum or atmosphere hardening. equalize.
Austenize : 1950/2225F (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 2100F (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
Temperature | 1950F | 2000F | 2050F | 2100F | 2150F | 2200F | |
---|---|---|---|---|---|---|---|
°C | °F | (1065C) | (1095C) | (1120C) | (1150C) | (1175C) | (1205C) |
As Quenched | 62 | 63 | 64 | 65 | 65 | 66 | |
540 | 1000 | 60 | 61 | 62 | 63 | 64 | 65 |
OPTIMUM FOR MAXIMUM TOUGHNESS AND EFFECTIVE STRESS-RELIEVING | |||||||
550 | 1025 | 59 | 60 | 62 | 63 | 64 | 65 |
565 | 1050 | 59 | 60 | 61 | 62 | 63.5 | 64 |
595 | 1100 | 57 | 59 | 60 | 61 | 62 | 63 |
610 | 1125 | 55 | 57 | 58 | 58.5 | 60 | 61 |
620 | 1150 | 53 | 54 | 55.5 | 57 | 58 | 59 |
NOTE A: RESULTS MAY VARY WITH HARDENING METHOD AND SECTION SIZE. SALT OR OIL QUENCHING WILL GIVE MAXIMUM RESPONSE. VACUUM OR ATMOSPHERE COOLING MAY RESULT IN UP TO 1-2 HRC POINTS LOWER. |
||||||
---|---|---|---|---|---|---|
MINIMUM TIME AT AUST TEMP (MINS) | 60 | 45 | 30 | 20 | 15 | 10 |
MINIMUM NUMBER OF TEMPERS (2 HRS) | 2 | 2 | 2 | 3 | 3 | 3 |
Surface Treatments
M-2 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: 217/255 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 M-2 is generally not recommended. 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) |