1. Basic mechanical properties
Yield strength (Rp0.2): ≥235 MPa.
Tensile strength (Rm): 360-510 MPa (labelled as 350-480 MPa in some data, possibly (related to process fluctuation).
Elongation (A): ≥21%, some scenes require ≥20%.
2. Physical Properties
Density: 7.85 g/cm³.
Modulus of elasticity: 206 GPa.
Thermal expansion coefficient: 11.6×10-⁶/°C.
3. Effect of process on properties
Cold-drawing/heat-treatment process: Optimise strength and toughness through cold-drawing and heat-treatment to meet the demand of high-precision hydraulic system.
Surface quality: high internal and external wall finish, no oxide layer, suitable for precision machining.
4. Comparison with similar standards
DIN 1630 St35: Mechanical properties (e.g. tensile strength, yield strength) are the same as DIN 2391, but the latter requires higher dimensional tolerances and surface finish.
No. 20 steel (GB/T 8163): yield strength (≥245 MPa) and tensile strength (410-550 MPa) are similar to St35, but St35 impurity control is more stringent.
