24 July 2021 Gear Steel Bar
30CrNiMo8 Gear Steel Bar
30CrNiMo8 is a quenched and tempered steel in the German DIN standard grade, which is equivalent to Chinese GB Standard grade 30Cr2Ni2Mo steel. 30CrNiMo8 steel has high yield strength, tensile strength and fatigue strength, as well as sufficient plasticity and toughness.
Generally, 30CrNiMo8 produced by electric arc furnace and oxygen top-blown converter for smelting, and the demanding ones are out-furnace refining, electroslag remelting or vacuum treatment, vacuum induction furnace smelting or double vacuum smelting, and suitable heat treatment. In addition to high-pressure chemical containers with high pressure and frequent fluctuations, it is also used to manufacture pressure pipes, plastic molds, important structures, etc., as well as to manufacture mechanical shafts, camshafts, wheel shafts, levers, and couplings with higher requirements. Rods, rocker arms, gears, etc.
30CrNiMo8 to HRB80 to do the following are very difficult, generally about HRB85 on it. It is widely used in high-pressure chemical tanks with high pressure and frequent fluctuations. It is also used in pressure pipelines, plastic molds, and important structures. Such as the Dongfang Steam Turbine Works FD70A, FD77A wind turbine main shaft made of high quality alloy steel (30CrNiMo8) forgings.
Chamecial Composition:
| C | Cr | Ni | Mo | Mn | P | S | Si |
| 0.26~0.34 | 1.8~2.2 | 1.8~2.2 | 0.3~0.8 | 0.3~0.6 | ≤0.035 | ≤0.03 | ≤0.4 |
Mechanical Properties:
| Yield Rp0.2 (MPa) | Tensile Rm (MPa) | Impact KV/Ku (J) | Elongation A (%) | Reduction in cross section on fracture Z (%) | As-Heat-Treated Condition | Brinell hardness (HBW) |
|---|---|---|---|---|---|---|
| 1050(≥) | 1250 (≥) | 31 | 12 | 44 | Solution and Aging, Annealing, Ausaging, Q+T,etc | 312 |
| Temperature (°C) | Modulus of elasticity (GPa) | Mean coefficient of thermal expansion 10-6/(°C) between 20(°C) and | Thermal conductivity (W/m·°C) | Specific thermal capacity (J/kg·°C) | Specific electrical resistivity (Ω mm²/m) | Density (kg/dm³) | Poisson’s coefficient, ν |
|---|---|---|---|---|---|---|---|
| 22 | - | - | 0.33 | - | |||
| 633 | 387 | - | 34.3 | 124 | - | ||
| 458 | - | 23 | 21.2 | 224 | 442 |