GB/T 32076.2-2015

This standard specifies test methods and requirements to verify that high-strength bolting assemblies are suitable for achieving and maintaining a specified preload (clamp force) during tightening. It is applied in the qualification and quality control of bolt, nut, and washer assemblies used in steel structures such as bridges, buildings, and heavy machinery where controlled tension is critical for joint integrity. The standard ensures that the components can consistently deliver the required preload without excessive relaxation or failure under service conditions.