Designation by Standards
| Steel No. | DIN | EN | AISI | JIS | ГОСТ |
| 1.2738 | 40CrMnNiMo8-6-4 | - | P20+Ni | / | / |
Chemical Composition (in weight %)
| C | Si | Mn | Cr | Mo | Ni | V | W | Others |
| 0.40 | 0.30 | 1.50 | 1.95 | 0.20 | 1.00 | - | - | S: 0.070 |
Description
This steel is in the category generally labeled as Mold Steels. Nickel and chromium are the alloying elements for hardness and toughness. Cold work tool steel with good machinability, excellent polishability, suitable for texturing. Improved through hardenability comapred to Mat.No. 1.2311.
Applications
Typically used for relatively low temperature applications such as die casting dies and injection molds, synthetic plastic moulds dies, for large moulds.
Physical properties (avarage values) at ambient temperature
Modulus of elasticity [103 x N/mm2]: 205
Density [g/cm3]: 7.80
Thermal conductivity [W/m.K]: 29.0
Specific heat capacity[J/g.K]: 0.46
Coefficient of Linear Thermal Expansion 10-6 oC-1
| 20-100oC | 20-200oC | 20-300oC | 20-400oC | 20-500oC | 20-600oC | 20-700oC |
| 11.7 | 12.3 | 13.0 | 13.3 | 13.7 | 13.7 | 14.0 |
Soft Annealing
Heat to 710-740oC, cool slowly. This will produce a maximum Brinell hardness of 235.
Stress Relieving
Stress relieving to remove machining stresses should be carried out by heating to 650oC, holding for one hour at heat, followed by air cooling. This operation is performed to reduce distortion during heat treatment.
Hardening
Harden from a temperature of 840-880oC followed by oil, air ot warm bath (180-220oC) quenching. Hardness after quenching is 52 HRC.
Tempering
Tempering temperature: See the data bellow.
Tempering Temperature (oC) vs. Hardness (HRC) vs. Tensile Stregth (N/mm2)
| 100oC | 200oC | 300oC | 400oC | 500oC | 600oC | 700oC |
| 52 | 51 | 49 | 46 | 42 | 36 | 28 |
| 1790 | 1730 | 1620 | 1480 | 1330 | 1140 | 920 |
Forging
Hot forming temperature: 1093-898oC.
Machinability
Machinability is relatively good at about 80% that of the W group water hardening steels.
Welding
This alloy is weldable by conventional methods. Contact the alloy supplier for details and weld procedures.
Remark
All technical information is for reference only.