All series of screw products

     The bolt performance grade is composed of two parts of numbers, which respectively represent the nominal tensile strength of the bolt and the yield ratio of the material. For example, the meaning of bolts with performance grade of 4.6 is: the number in the first part (4 in 4.6) is 1 / 100 of the nominal tensile strength (n / mm2) of bolt material, that is, Fu ≥ 400N / mm2; The number in the second part (6 in 4.6) is 10 times of the yield ratio of bolt material, that is, FY / Fu = 0.6; Product of two numbers (4) × 6 = "24") is 1 / 10 of the nominal yield point (or yield strength) (n / mm2) of bolt material, that is, FY ≥ 240n / mm2.

    According to the manufacturing accuracy, ordinary bolts of steel structure can be divided into three levels: A, B and C. A. Grade B is refined bolt, which is generally used for mechanical products, and grade C is rough bolt. Unless otherwise specified, ordinary bolts of steel structure are generally ordinary coarse grade C bolts with performance grade of 4.6 or 4.8.