Audited Supplier
powder high speed steel
Special Steel Bar
AISI, ASTM, DIN, JIS, GB, BS
Stainless Steel Scrap
Forged
Bar
Polished
High-strength Steel Plate, Wear Resistant Steel, Silicon Steel, Cold Heading Steel, Free Cutting Steel, Mold Steel
Die Steel Bar
2500-5500mm
HSS
Gear Hob
OEM
Smooth
N/M
6-400mm
China
7226911000
Product Description
Typical Applications:
Hobs
Powder Compaction Tooling
Broaches
Milling Cutters
Die Inserts
Wear Parts
Guide Rolls
Note: These are some typical applications. Your specific application should not be undertaken without independent study and evaluation for suitability.
Chemical Composition:
| PM121/Rex121 | Carbon | Chromium | Vanadium | Tungsten | Molybdenum | Cobalt | Sulfur |
| 3.4% | 4.0% | 9.5% | 10.0% | 5.0% | 9.0% | 0.03% (0.10%)* |
Physical Properties:
Elastic Modulus 31X106psi 214 GPa
Specific Gravity 8.26
Density 0.298 lbs/in3 8.255g/cm3
Coefficient of Thermal Expansion
°F °C in/in/°F mm/mm/°C
70-400 20-200 6.0 X 10-6 10.8 X 10-6
70-600 20-315 6.15 X10-6 11.1 X 10-6
70-800 20-425 6.33 X10-6 11.4 X 10-6
70-1000 20-540 6.52 X10-6 11.7 X 10-6
70-1200 20-650 6.75 X10-6 12.1 X 10-6
Relative Mechanical Properties:
Wear Resistance
Depending on the application, the wear resistance of
CPM Rex 121 is approximately 50-100% better than CPM
Rex T15, CPM Rex 76 or CPM 10V.
Impact Toughness
Depending on the heat treatment, the impact toughness of
CPM Rex 121 is approximately comparable to that of CPM
15V or conventionally melted T15.
Red Hardness
The red hardness of CPM Rex 121 is higher than that of
CPM Rex 76. CPM Rex 121 can retain a room temperature
hardness of HRC 60 even after tempering at 1200°F (650°C).
Its high red hardness may be particularly useful for high cutting
speed operations.WhenCPM Rex 121 is used in place of
conventional cobalt-bearing high speed steels in cutting
tools, cutting speeds may be increased by approximately
25%-50%, depending on application experience.
Thermal Treatments:
Annealing:
Heat to 1650° F (900°C), hold 2 hours, slow cool no faster than 25°F (15° C) per hour to 1000° F (540°C), then furnace cool or cool in still air to room temperature. Annealed Hardness: Approx. BHN 360/410 (HRC 38/44)
Stress Relieving
Annealed parts: Heat to 1100-1300° F (595-705°C), hold 2 hours, then air cool or furnace cool. Hardened parts: Heat to 25-50°F (15-30°C) below original tempering temperature, hold 2 hours, then air cool or furnace cool.
Hardening (Salt Bath or Vacuum Furnace preferred.)
Pre-heat: 1500-1550°F (815-845°C), hold long enough to soak through. A second pre-heat at 1850-1950°F (1010 1065°C) is recommended when hardening from over 2100°F (1150°C)
Austenitize: 1875-2200°F (1025-1205°C) Hold time at temperature: 5-30 minutes depending on temperature.
Quench: Quench rapidly to below 1100°F (595°C), equalize then air cool to hand warm, 125°F (50°C). Salt or interrupted oil quench usually gives the best heat treat response for high speed steels. Vacuum hardening may result in slightly lower hardness for larger tools. The quench rate from the hardening temperature to below 1100°F (595°C) is critical to achieve optimum results. The cooling rate below 1000°F (540°C) may be slower to minimize distortion if desired.
Temper: Temper 2 to 4 times at 1000°F (540°C) or higher. Hold at least 2 hours at temperature for each temper. (From 2 to 4 tempers are required, depending on exact hardening temperature.) Air cool to room temperature between tempers.
Straightening: Best when done warm 500-1000°F (260 540°C). Straightening after salt quenching, before cooling to below 500°F (260°C) is preferred if possible. This grade has limited toughness; straightening may present a risk of cracking.
Surface Treatments:
PM121/ Rex 121 can be nitrided or PVD coated if desired. If a CVD treatment is used, subsequent hardening is required and may result in undesirable distortion. The high red hardness of CPM Rex 121 makes it a particularly good substrate for TiAlN or similar coatings designed for higher temperature exposure.
