24 July 2021 Cold Heading Steel Bar
ML30CrMo Cold Heading Steel Bar
ML30CrMo is the Chinese standard GB/T 6478-1986 cold heading steel, ML30CrMois a common steel grade which used to produce high strength bolt of class 12.9.This product has characteristics of the uniform-chemical composition, low percentage of harmful elements, high purity, slight decarburization, good surface quality. After spheroid annealing, this product has the characteristics of good cold heading properties, stable heat-treatment properties, and good hardenability.
ML30CrMo Chemical composition:
| C(％) | Si(％) | Mn(％) | P(％) | S(％) | Cr(％) | Mo(％) | Al(%) |
| 0.26-0.34 | Max 0.30 | 0.60-0.90 | 0.035 | 0.035 | 0.80-1.10 | 0.15-0.25 | — |
ML30CrMo Physical Properties:
| 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 |
| 34 | - | - | 0.22 | - | |||
| 622 | 955 | - | 32.3 | 114 | - | ||
| 426 | - | 11 | 21.2 | 133 | 121 |
ML30CrMo Mechanical Properties:
| Yield Rp0.2 (MPa) | Tensile Rm (MPa) | Impact J) | Elongation A (%) | Reduction in cross section on fracture Z (%) | As-Heat-Treated Condition | Brinell hardness (HBW) |
| 891 (≥) | 262 (≥) | 43 | 11 | 33 | Solution and Aging, Annealing, Ausaging, Q+T,etc | 213 |