High Speed Steel
PM M-48
PM M-48 High Speed Steel Data Sheet
Chemical Composition
| Carbon | 1.50% |
| Molybdenum | 5.25% |
| Chromium | 3.75% |
| Cobalt | 8.50% |
| Vanadium | 3.10% |
| Tungsten | 9.75% |
| Sulfur | 0.07% |
Typical Applications
| Broaches | Milling Cutters | |
| Gear Hobs | Tool Bits | |
| Taps | End Mills | |
| Shaper Cutters | High Hardness Forming Tools |
Thermal Treatments
Preheat : 1500/1550F (820/845C), equalize, Second preheating stage at 1800/1850F (1010/1040C)recommended for vacuum or atmosphere hardening. equalize.
Austenize : 2100/2200F (1150/1205C), 30/45 minutes at temperature. Standard recommendation to achieve RC 67-69 after tempering is to use 2150/2175F (1175/1190C)
Quench : Salt, oil or atmosphere quench to 1000-1100F(540-595C), equalize, then air cool to below 125F(50C) or hand warm. A fast quench rate from 1850 (1010C) through 1100F(595C) range is critical to achieve optimum heat treat results.
Temper : 1000F (540C) minimum, hold 2 hours at temperature, air cool. Triple tempering is required, quadruple tempering is recommended.
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 | 2100F | 2125F | 2150F | 2175F | 2200F | |
|---|---|---|---|---|---|---|
| °C | °F | (1150C) | (1165C) | (1175C) | (1190C) | (1205C) |
| As Quenched | 68 | 68 | 67 | 66.5 | 66.5 | |
| 540 | 1000 | 67 | 67.5 | 68 | 68.5 | 69 |
| OPTIMUM FOR MAXIMUM TOUGHNESS AND EFFECTIVE STRESS-RELIEVING | ||||||
| 550 | 1025 | 66.5 | 67 | 67.5 | 68 | 68.5 |
| 565 | 1050 | 65.5 | 66.5 | 67 | 67.5 | 68 |
| 595 | 1100 | 63 | 64 | 65 | 66 | 66.5 |
| 620 | 1150 | 59 | 60 | 51.5 | 63 | 64 |
| 650 | 1200 | 53 | 55 | 57 | 59 | 60 |
| 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) | 10 | 10 | 5 | 5 | 3 |
| MINIMUM NUMBER OF TEMPERS (2 HRS) | 3 | 3 | 3 | 4 | 4 |
Surface Treatments
PM M-48 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: 285/311 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, or 1000F (540C)minimum, hold two hours, cool in still air.
Welding
Welding of PM M-48 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) | (214 GPa) |
| Density | 0.298 lb/in3 | (8255 kg/M3) |
| Thermal Conductivity | 11.74 BTU/hr./ft./F | 19 W/m/ °K) |