P-20
P-20 Grade Introduction:
P20 is an alloy tool steel which offers good machine ability even in the hardened and tempered (Brinell 300) condition. This steel gives an excellent polished finish and is one of the most widely accepted specifications for machine cut plastic molds and casting dies. P20 is often supplied in the hardened and tempered condition ready for machining. In this condition it gives excellent wear resistance but if maximum surface hardness is required for compression molding plastic dies or similar tools, the steel can be case hardened or nitride. For better machinability a higher Sulphur version P20S is available. For improved through hardenability in larger sections we also offer 1.2738 P20N
P-20 Grade Application:
- Plastic molds
- Die holders
- Zinc die casting dies
- Backers
- Bolsters
- Injection molds
- Shafts
- Rails
- Wear strips
P-20 Equivalent Grades:
| Country |
USA |
German |
GB/T |
| Standard |
ASTM A681 |
DIN EN ISO 4957 |
GB/T 1299 |
| Grades |
P20 |
1.2311 |
3Cr2Mo |
P-20 Chemical Composition:
| Element |
C |
Si |
Mn |
P |
S |
Cr |
Mo |
Cu |
| Content (%) |
0.28-0.40 |
0.20-0.80 |
0.60-1.00 |
0.03 |
0.03 |
1.40-2.00 |
0.30-0.55 |
0.25 |
Mechanical Properties:
| Properties |
Metric |
Imperial |
| Hardness, Brinell (typical) |
300 |
33 |
| Hardness, Rockwell C (typical) |
30 |
30 |
| Tensile strength, ultimate |
965-1030 MPa |
140000-150000 psi |
| Tensile strength, yield |
827-862 MPa |
120000-125000 psi |
| Elongation at break (in 50 mm (2″)) |
20.0% |
20.0% |
| Compressive strength |
862 MPa |
125000 psi |
| Charpy impact (V-Notch) |
27.1-33.9 J |
20.0-25.0 ft-lb |
| Poisson’s ratio |
0.27-0.30 |
0.27-0.30 |
| Elastic modulus |
190-210 GPa |
27557-30457 ksi |
Physical Properties:
| Properties |
Metric |
Imperial |
| Density |
7.85 g/cc |
0.284 lb/in³ |
Thermal Properties:
| Properties |
Unit |
T (°C) |
Treatment |
| Thermal expansion |
12.8 x 10-6/ºC |
20-425 |
– |
Forging Properties:
Heat slowly, allowing sufficient time for the steel to become heated through. Begin forging at 1050°C. Do not forge below 930°C reheating if necessary. After forging, cool very slowly.
Stress Relieving:
When dies are heavily machined, we recommend stabilizing just before finish machining in order to relieve machining strains. Heat to 460-500°C. Soak well and allow to cool in the air.