A bolt is one of the most commonly used fasteners in mechanical manufacturing and engineering installation. It usually consists of a head and a threaded shank, and is used with a nut to realize detachable connection of two or more components. Bolts feature simple structure, reliable connection, convenient assembly and disassembly, and high universality. They are widely used in construction engineering, mechanical equipment, automobile manufacturing, rail transit, household appliances, steel structures and other fields. According to material, strength grade, thread type and application, bolts can be divided into hex bolts, socket head cap screws, expansion bolts, anchor bolts, flange bolts and other types, making them indispensable basic parts in industrial production and daily assembly.