Pm121/Rex121 HSS Powder Metallurgy High Speed Steel Round Bars/Flats/Sheets/Wire

• Type: Special Steel Bar
• Standard: AISI, ASTM, DIN, JIS, GB, BS
• Composition: Stainless Steel Scrap
• Technique: Forged
• Shape: Bar
• Surface Treatment: Polished
• Model NO.: powder high speed steel
• Special Use: High-strength Steel Plate, Wear Resistant Steel, Silicon Steel, Cold Heading Steel, Free Cutting Steel, Mold Steel
• Application: Die Steel Bar
• Length: 2500-5500mm
• Material: HSS
• Usage: Gear Hob
• Customized Support: OEM
• Transport Package: N/M
• Specification: 6-400mm
• Trademark: Smooth
• Origin: China
• HS Code: 7226911000
• Production Capacity: 1000ton/Month

Product Description

Detailed Photos

Product Description

 

PM121/Rex 121 is a high vanadium cobalt-bearing tool steel designed to offer the highest combination of wear resistance, attainable hardness, and red hardness available in a high speed steel. Its superior red hardness permits higher cutting speeds compared to other high speed steels. Its superior wear resistance, owing to its high vanadium content, helps to maintain a sharp cutting edge at increased cutting speeds. PM121/Rex 121 also bridges the performance gap between high alloy tool steels and carbide materials. It may be used for cutting tools, where high cutting speeds demand higher heat resistance, but carbide is too brittle, or for high wear tooling applications (punches and dies) where carbide tools are too fragile. The CPM process results in a homogeneous microstructure with a finer, more uniform carbide distribution imparting superior dimensional stability, grindability and toughness when compared to steels produced by conventional processes. The CPM process also allows the design of more highly alloyed grades which cannot be produced by conventional steelmaking.

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.