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Designation by Standards

Steel No. DIN EN AISI JIS ГОСТ
1.2379 X155CrVMo12-1 † X153CrMoV12 D2 SKD11 X12MΦ


Chemical Composition (in weight %)

C Si Mn Cr Mo Ni V W Others
1.55 0.25 0.30 11.50 0.70 - 1.00 - -


Description
This alloy is one of the cold work, high carbon, high chromium type tool steels. D2 is a deep hardening, highly wear resistant alloy. It hardens upon air cooling so as to have minimum distortion after heat treatment.

Applications
Used for long run tooling applications where wear resistance is important, such as blanking or forming dies and thread rolling dies, cutting tools, stamping, woodworking, moulding tools for plastics. Toughness better than in D3. Possibility of nitriding.

Physical properties (avarage values) at ambient temperature
Modulus of elasticity [103 x N/mm2]: 210
Density [g/cm3]: 7.70
Thermal conductivity [W/m.K]: 20.0
Electric resistivity [Ohm mm2/m]: 0.65
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 20-800oC
9.8 11.7 12.1 12.8 12.9 13.0 13.2 13.5


Soft Annealing
Heat to 840-880oC, cool slowly. This will produce a maximum Brinell hardness of 255. To secure uniform softness.

Stress Relieving
Stress relieving to remove machining stresses should be carried out by heating to 650-700oC, 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 1000-1040oC followed by oil, warm bath (500-550oC, cooling bath or air. Hardness after quenching is 62-64 HRC.

Tempering
Tempering temperature: 150-550oC.

Tempering Temperature (oC) vs. Hardness (HRC)

100oC 200oC 300oC 400oC 500oC 525oC 550oC 600oC 700oC
63 61 58 58 59 58 56 51 35


Forging
Hot forming temperature: 1050-850oC.

Machinability
Machinability of D2 is poor. Using the water hardening simple alloy tool steels (W group) as a base of 100 % the D2 alloy would rate about 50 % in machinability.

Corrosion Resistance
D2 is a steel alloy and is not corrosion resistant. It will rust unless protected.

Cold working
Cold working by conventional methods may be done with the alloy in the annealed condition.

Welding
Consult the alloy supplier for information as to welding.

Remark
All technical information is for reference only.