(AISI P20)
| Typical Chemistry | |
| Carbon | 0.30% |
| Manganese | 0.75% |
| Silicon | 0.50% |
| Chromium | 1.70% |
| Molybdenum | 0.40% |
| Typical Applications | ||
| Zinc Diecasting Dies | Holders and Backers | |
| Injection Molds | Compression Molds | |
| Prototype Molds & Dies | Transfer Molds | |
- Hardening
CSM 2 is supplied prehardened at two hardnesses. The usual hardness is about 300 BHN (about 30/32 HRC). If additional compressive resistance is required, our CSM 2 High Hard is available at about 340 BHN (about 35/38 HRC). Further heat treating is normally not required. If desired CSM 2 may be heat treated for higher strength. Care must be exercised to minimize the risk of distortion or cracking due to oil quenching.
Preheat: 1250/1350F, equalize.
High heat: 1500/1550F, hold 30-45 minutes at temperature.
Quench: Oil quench to 150/200F. Temper immediately.
Temper: 400-1200F, hold one hour per inch of thickness (two hours minimum). Temper twice.
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| Tempering Temperature °F |
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| 400 | 48.5 |
| 600 | 46.5 |
| 800 | 43.5 |
| 1000 | 39.5 |
| 1200 | 26.5 |
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CSM 2 may be nitrided by most commercial procedures, resulting in a surface hardness of 55-65 HRC. CSM 2 may also be carburized, resulting in a case hardness of 53/57 HRC.
Annealing
Heat to 1450/1500F, hold two hours at temperature.
Cool slowly (50F/hour maximum) to 1200F and hold until equalized.
Air cool to room temperature.
Typical annealed hardness: 187/223 BHN
Stress Relieving
Heat to temperature shown below. Hold two hours minimum. Air cool.
Stress relieving temperature:
Standard (293/321 BHN): 1000F
High-hard (321/353 BHN): 950F
Custom heat treated: 50F below tempering temperature used.
Welding
Welding procedures similar to 4140 or 4340 should be followed. P20, 4130 or 4140 filler material is acceptable.
Prehardened material: Preheat to 800/900F. Maintain above 800F during welding. Cool to hand warm (150F) after welding. Temper twice at 900F.
Customer heat treated material: Preheat and temper after welding at 50F below tempering temperature.
Physical Properties
Modulus of Elasticity ...................................................................30 psi x 106
Density .............................................................................................0.284 lb/in3
Thermal Conductivity .................(200F)................................ 24 BTU/hr/ft/°F
Thermal Expansion
RT - 500F ...................................................................6.84 x 10-6 in./in./°F
RT - 800F ..................................................................7.10 x 10-6 in./in./°F
RT - 1000F ................................................................7.60 x 10-6 in./in./°F