Heat treatment of steel is a process that involves heating, insulation, and cooling the steel in a solid state to change its internal structure and obtain the desired properties. Heat treatment does not change its chemical composition and shape, which can improve the process performance of steel and significantly enhance its usability, thereby unleashing the potential of steel and improving the usability and service life of workpieces. However, it has little effect on cast iron Therefore, cast iron is generally not subjected to heat treatment in factories.
Some parts in production, such as gears, spline shafts, piston pins, etc Its surface requires high hardness and wear resistance, while the core requires a certain strength and sufficient toughness. Ordinary quenching and tempering processes cannot achieve this, and surface heat treatment is required to strengthen the surface.
Surface heat treatment can be divided into two categories: one is heat treatment that only changes the surface structure without changing the surface chemical composition, known as surface quenching; Another type is heat treatment that simultaneously changes the surface chemical composition and structure It is called chemical heat treatment.