24 July 2021 Cold Heading Steel Bar
SWRCH25K Cold Heading Steel Bar
SWRCH25K Cold heading steel molding steel, cold heading is used at room temperature one or more impact loading, widely used in the production of screws, pins, nuts and other standard parts. Cold heading process can save raw materials, reduce costs, but also by cold hardening to improve the tensile strength of the workpiece to improve performance, cold forging steel must have a good cold forging performance, steel S and P and other impurities to reduce the Steel surface quality requirements are strict, often using high-quality carbon steel, if the steel carbon steel is greater than 0.25%, should be ball annealing heat treatment to improve the cold heading performance of steel.
SWRCH25K belongs to the 6.8 grade bolt steel, generally used in the power industry. Can prevent brittle fracture. The material made out of the 6.8 grade bolts do not need heat treatment, can reduce the production cost.
Chemical Composition:
| C(％) | Si(％) | Mn(％) | P(％) | S(％) | Al(%) |
|---|---|---|---|---|---|
| 0.22-0.28 | 0.10-0.35 | 0.30-0.60 | 0.030 | Max 0.035 | — |
Mechanical Properties:
| Proof strength Rp0.2(MPa) | Tensile strength Rm(MPa) | Impact energy KV(J) | Elongation at fracture A(%) | Reduction in cross section on fracture Z(%) | As-Heat-Treated Condition | Brinell hardness(HBW) |
|---|---|---|---|---|---|---|
| 968(≥) | 792(≥) | 34 | 23 | 11 | Solution and Aging,Annealing,Ausaging,Q+T,etc | 212 |
| 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 |
|---|---|---|---|---|---|---|---|
| 31 | - | - | 0.31 | - | |||
| 278 | 141 | - | 22.3 | 214 | - | ||
| 511 | - | 22 | 32.2 | 314 | 321 |