The yield strength (ReH) shall be no less than 235 MPa; the tensile strength (Rm) shall be strictly controlled within the range of 360 to 510 MPa; and the elongation after fracture (A) shall be guaranteed to be 26% or higher. With regard to the control of chemical composition through smelting analysis, the carbon (C) content is capped at 0.17%, the manganese (Mn) content is limited to a maximum of 1.40%, whilst harmful elements such as phosphorus (P) and sulphur (S) are strictly restricted to 0.035% or less.