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) |