HCHCR
HCHCR Grade Introduction:
Cold-work tool steels which include D2, D3, D4, D5, and D7 steels are high-carbon, high-chromium steels. Apart from D3 steel all group D steels have 1% Mo and are air hardened. Type D3 steel is oil-quenched; though small sections can be gas quenched after austenitization using vacuum. As a result, tools made with type D3 steel tend to be brittle during hardening. Type D2 steel is the most commonly used steel among the group D steels. The D3 steels contain 1.5 to 2.35% of carbon and 12% of chromium.
HCHCR Grade Application:
- Highly stressed cutting
- Punching tools for thin sheets
- Shear blades for cutting
- Profile rolls
- Stone processing tools
- Pressure pads
HCHCR Equivalent Grades:
| Country |
USA |
German |
Japan |
| Standard |
ASTM A681 |
DIN EN ISO 4957 |
JIS G4404 |
| Grades |
D3 |
1.2080/X210Cr12 |
SKD1 |
HCHCR Chemical Composition:
| Element |
C |
Si |
Mn |
P |
S |
Cr |
Ni |
V |
Cu |
W |
| Content (%) |
2.00-2.35 |
0.60 |
0.60 |
0.03 |
0.03 |
11.00-13.50 |
0.30 |
1.00 |
0.02 |
1.00 |
Mechanical Properties:
| Properties |
Metric |
Imperial |
| Izod impact unnotched |
28.0 J |
20.7 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 |
7.7 x 1000 kg/m3 |
0.278 lb/in3 |
| Melting point |
1421°C |
2590°F |
Thermal Properties:
| Properties |
|
T (°C) |
Treatment |
| Thermal expansion |
12 x 10-6/ºC |
20-100 |
– |
Forging Properties:
Pre-heat at 900-950°C then raise temperature to 1050-1100°C. Soak until uniformly heated. D3 tool steel is relatively hard at elevated temperature. Therefore, initial hammer blows must be light and the temperature must not be allowed to fall below 1020°C until the metal begins to flow. Final forging should not be done below 900°C.
Stress Relieving:
When tools are heavily machined, ground or otherwise subjected to cold work, the relief of internal strains is advisable before hardening to minimize the possibility of distortion. Stress relieving should be done after rough machining. To stress relieve, heat the steel component to 600-650°C. Soak well and cool in the furnace or in air. The tools may then be finish machined before hardening.