High Speed Steel
Z-Max PM
Z-Max PM High Speed Steel Data Sheet
Z-Max PM® is an ultra high performance HSS produced by powder metallurgy methods that can be heat treated to a maximum attainable hardness of HRc 68-70. It offers maximized levels of wear resistance, red hardness, attainable hardness, and compressive strength compared to other cobalt HSS grades. It is suitable for use in various heavy duty cutting tool applications involving difficult to machine materials as well as selected cold work applications when under hardened to optimize toughness. It can be considered as a possible alternative to carbide when toughness is a concern. The particle metallurgy processing also provides improved machinability, grindability, heat treat response, and dimensional stability when compared to similar grades produced by conventional methods.
Chemical Composition
| Carbon | 2.0% |
| Molybdenum | 5.0% |
| Chromium | 4.0% |
| Cobalt | 9.0% |
| Vanadium | 5.0% |
| Tungsten | 10.0% |
Typical Applications
| Broaches, Taps | Milling Cutters | |
| Gear Hobs | Tool Bits, End Mills | |
| Powder Compaction Tooling | Precision Wear Parts | |
| 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
Z-Max PM 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 Z-Max PM 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 | 0.292 lb/in3 | (8255 kg/M3) |
| Thermal Conductivity | 11.74 BTU/hr./ft./F | 19 W/m/ °K) |