What is Flame Hardening? What is it for?

Hardening is the heating and cooling process performed to increase the tensile strength and hardness of steel and to increase its strength. The material to be hardened is subjected to heating to a suitable temperature, followed by cooling. After this process, the material is hardened. Flame hardening is one of the most preferred surface hardening methods. Metal materials are heated with flames at high temperatures. Then, the hardening process is carried out by quenching. As a result of flame hardening, a hard surface is obtained.
How is Flame Hardening Done?
Flame hardening is applied to parts made of alloy steels, medium carbon steels, mild steels and cast iron. In the flame hardening method, the hardening process is carried out by using direct heat. Flame hardening processes can be performed on all surfaces of the parts. The temperature of the flame used in flame hardening, heating time, heating rate and flame extinguishing temperature vary depending on the type of material. Acetylene and oxygen are used in flame hardening. The tips of the flamethrower are adjusted to suit the material to be cured. The surface to be hardened is heated to quenching temperature with the flame of a gas burned with oxygen. Water is suddenly applied to the part whose surface reaches the required temperature. This process is usually done by spraying water on the material. Cooling occurs immediately after heating. The flame hardening process reaches a surface hardness of approximately 55-60 HRC, depending on the material. There is no change in the chemical composition of the material during flame hardening. The area of the material to be hardened is heated to the appropriate temperature and hardened by adding water after the austenitization process. For this reason, the flame hardening process can be performed on steels suitable for hardening and generally containing carbon between 0.3 and 0.6.
Advantages of Flame Hardening
High hardness surfaces are obtained by the flame hardening method. Deterioration in the material remains at a low level. It is carried out in a shorter time compared to other surface hardening processes such as nitriding and carburizing. The cost of flame hardening is lower. It can be adjusted according to the environment and conditions. It can be applied to the area to be hardened. The surfaces of materials that are too large to fit into ovens can be hardened by flame hardening. After the flame hardening method, there is no change in the chemical composition of the material. http://www.aht.com.tr/