Tempering is to reduce the brittleness of the steel, and the quenched steel is kept at a suitable temperature above room temperature and below 710 ° C for a certain period of time, and then cooled, this process is called tempering.
Annealing, normalizing, quenching and tempering are the "four fires" in the overall heat treatment. Among them, the quenching and tempering are closely related, and often used together, they are indispensable.
The heat treatment process generally includes three processes of heating, heat preservation and cooling, and sometimes only two processes of heating and cooling. These processes are connected to each other and cannot be interrupted.
Surface hardening is a process of quenching the surface of a workpiece. The surface of the workpiece is rapidly heated, austenitized and rapidly cooled to obtain a martensite structure, while the core still maintains an original annealing, normalizing or quenching state with good plasticity and toughness. After surface quenching, low temperature tempering is required to reduce quenching stress and reduce brittleness. Surface quenching can effectively improve the hardness and wear resistance of t
Annealing is to heat the workpiece to a suitable temperature, using different holding time according to the material and the workpiece size, and then slowly cooling (the slowest cooling rate), in order to achieve or be close to the equilibrium of the metal internal organization, and obtain good process performance and use properties, or prepare for further quenching (annealing: heat treatment processes that heat, hold, and cool metals and their alloys to bring their structures to or near equilib