A set wrench is a hand tool used to install and remove threaded fasteners, using the lever principle to apply a moment, usually made of carbon structural steel or alloy structural steel. Its basic types are divided into dead wrenches and live wrenches, and are subdivided into dull wrenches, torx wrenches, socket wrenches, etc., which are suitable for twisting bolts or nuts of different specifications. The socket wrench consists of a multi-specification socket head and accessories, which can be operated in tight spaces.
These tools are divided into household, professional, industrial, and aerospace grades according to usage scenarios, with industrial-grade products focusing on high strength and durability. The surface treatment process includes bright chrome, sub-chromium, electrophoresis, etc., to improve rust resistance. As a representative of the set category, socket wrenches are often equipped with handles, adapters and other components, expanding the range of applications through modular design. The material is mostly chrome vanadium steel (CR-V), which takes into account hardness and elasticity, and the head needs to meet specific hardness standards to ensure functionality.