Surface heat treatment of steel

⑴ Surface quenching:

The surface of the steel part is quickly heated to above the critical temperature, but the heat will be cooled quickly before reaching the core in the future, so that the surface layer can be quenched in the martensite structure, and the core does not undergo a phase change The purpose of hardening the surface without changing the core is achieved. Suitable for medium carbon steel.

⑵Chemical heat treatment:

It refers to infiltrating the atoms of chemical elements into the surface layer of the workpiece with the ability of atomic diffusion at high temperature to change the chemical composition and structure of the surface layer of the workpiece, so as to achieve the specific structure and structure of the steel surface layer A performance heat treatment process. According to different types of infiltrating elements, chemical heat treatment can be divided into four types: carburizing, nitriding, cyaniding and metalizing methods.

Carburization: Carburization refers to the process of infiltrating carbon atoms into the steel surface layer. It is also to make the low-carbon steel workpiece have a high-carbon steel surface layer, which is then quenched and tempered at low temperature, so that the surface layer of the workpiece has high hardness and wear resistance, and the middle part of the workpiece still maintains the toughness and low carbon steel Plasticity.

Nitriding: Also known as nitriding, it refers to the process of infiltrating nitrogen atoms into the surface layer of steel. Its purpose is to increase the hardness and wear resistance of the surface layer as well as to improve fatigue strength and corrosion resistance. At present, the gas nitriding method is mostly used in production.

Cyanidation, also known as carbonitriding, refers to the process of simultaneously infiltrating carbon atoms and nitrogen atoms in steel. It makes the steel surface have the characteristics of carburizing and nitriding.

Metal penetration: refers to the process of infiltrating the surface layer of steel with metal atoms. It is to alloy the surface layer of steel so that the surface of the workpiece has certain alloy steel and special steel characteristics, such as heat resistance, wear resistance, oxidation resistance and corrosion resistance. Commonly used in production are aluminizing, chromizing, boronizing, siliconizing, etc.