Chemical Composition
The following table shows the chemical composition of D2 tool steels.
| Element | Content (%) |
|---|---|
| C | 1.40 – 1.60 |
| Mn | 0.60 |
| Si | 0.60 |
| Co | 1.00 |
| Cr | 11.00 – 13.00 |
| Mo | 0.70 – 1.20 |
| V | 1.10 |
| P | 0.03 |
| Ni | 0.30 |
| Cu | 0.25 |
| S | 0.03 |
Physical Properties
The physical properties of D2 tool steels are outlined in the following table.
| Properties | Metric | Imperial |
|---|---|---|
| Density | 7.7 x 1000 kg/m3 | 0.278 lb/in3 |
| Melting point | 1421°C | 2590°F |
Mechanical Properties
The mechanical properties of D2 steels are tabulated below:
| Mechanical Properties | Metric | Imperial |
|---|---|---|
| Hardness, Knoop (converted from Rockwell C hardness) | 769 | 769 |
| Hardness, Rockwell C | 62 | 62 |
| Hardness, Vickers | 748 | 748 |
| Izod impact unnotched | 77.0 J | 56.8 ft-lb |
| Poisson’s ratio | 0.27-0.30 | 0.27-0.30 |
| Elastic modulus | 190-210 GPa | 27557-30457 ksi |
Thermal Properties
The following table shows the thermal properties of D2 steels.
| Properties | Conditions | ||
|---|---|---|---|
| T (°C) | Treatment | ||
| Thermal expansion | 10.4 x 10-6/ºC | 20-100 | – |
Fabrication and Heat Treatment
Heat Treatment
D2 steels should be preheated very slowly to 815ºC (1500ºF) and then temperature can be increased to 1010ºC (1850ºF). They are then held at 1010ºC (1850ºF) for 20 to 45 minutes and air cooled (air quenched).
Forging
Forging of D2 steels can be done from 1065ºC (1950ºF) down to 954ºC (1750ºF). Do not forge below 926ºC (1700ºF).
Annealing
Annealing of D2 steels should be done at 871 to 898ºC (1600 to 1650ºF) followed by slow furnace cooling at 4.4ºC (40ºF) per hour or less.
Tempering
D2 steels can be tempered at 204ºC (400ºF) for achieving Rockwell C hardness of 61 and at 537ºC (1000ºF) for a Rockwell C hardness of 54.
Applications
D2 tool steels are used for long run tooling applications, where wear resistance is important, such as blanking or forming dies and thread rolling dies.
