紧固件机械性能(Part 7):螺栓和螺钉扭矩试验和最小扭矩(M1-M10) ISO 898-7 - 1992

　　This part of ISO 898 specifies a torsional test for the determination of the breaking torque of bolts and screws with nominal diameters 1 mm to 10 mm With property classes 8.8 to 12.9 in accordance with ISO 898-1. The test applies to bolts and screws with thread less than M3 for which no breaking and proof loads are indicated In ISO 898-1, as well as to short bolts and screws with nominal diameters 3 mm to 10 mm which cannot be subjected to a tensile test.

　　The minimum breaking torques are not valid for hexagon socket set screws.