Composition of hexagon socket screws

Internal hexagonal combination screws are generally composed of a combination of an internal hexagonal cylindrical head screw, a spring washer, and a flat washer, which are threaded and fastened together. Internal hexagonal combination screws are divided into 4.8 grade internal hexagonal combination screws and 8.8 grade internal hexagonal combination screws according to their materials. The general material on the market is grade 8.8 internal hexagonal combination screws. Generally, manufacturers use screw wire 10B21 for production. Harden to 8.8 level, but require hydrogen removal to prevent the spring washer and internal hexagonal bolt from breaking.