Shandong Zhongao Steel Co. LTD. is a large-scale iron and steel enterprise integrating sintering, iron making, steel making, rolling, pickling, coating and plating, tube making, power generation, oxygen production, cement and port. The main products include sheet (hot rolled coil, cold formed coil, open and longitudinal cut sizing board, pickling board, galvanized sheet), section steel, bar, wire, welded pipe, etc. The by-products include cement, steel slag powder, water slag powder, etc. Among them, fine plate accounted for more than 70% of the total steel production.1. According to the shape of the head: hexagonal head, round head, square head, countersunk head and so on. The hexagonal head is the most commonly used. The general countersunk head is used where the connection is required. 2. U-bolt, both ends of the thread can be combined with the nut, mainly used to fix the pipe such as water pipe or flake such as car plate spring.The application scope of bolts is: electronic products, mechanical products, digital products, electrical equipment, mechanical and electrical products. Bolts are also used in ships, vehicles, hydraulic engineering and even chemical experiments. Bolts are used in a lot of places anyway. Such as digital products above the use of precision bolts. Microbolts for DVD, camera, glasses, clocks, electronics, etc.; General bolts for television, electrical products, Musical Instruments, furniture, etc.; As for engineering, construction, bridge is the use of large bolts, nuts; Traffic instruments, aircraft, trams, automobiles, etc. are used for large and small bolts.