There is a certain relationship between the service life of the spiral steel pipe
and the surface decarburization of the spiral pipe. If the surface is decarburized, the strength and wear resistance of the spiral steel pipe will be reduced, which directly affects the service life of the spiral steel pipe. If the decarburized layer on the spiral pipe is not cleaned, the surface layer hardness and wear resistance of the spiral steel pipe will be correspondingly reduced, and in the process of quenching, the surface of the workpiece will be caused by the change of the volume of the inner and outer layers. A crack is formed.
In order to solve the decarburization problem of the surface, the heat treatment process is mainly processed because the decarburization and the oxidation of the spiral steel pipe are simultaneously performed. Therefore, in the process of heat treatment, the spiral steel pipe should not be in contact with the air as much as possible. This can improve the phenomenon of decarburization.
The medium causing decarburization on the surface of the spiral tube is mainly an oxidizing gas such as oxygen, water vapor and carbon dioxide. When these gases are in contact with the heated spiral tube, the spiral tube is oxidized and decarburized, thereby controlling the carbon dioxide in the furnace and The proportion of carbon monoxide is also very important.
In fact, it is also effective to add a protective gas nitrogen to the spiral steel pipe forging furnace. The nitrogen gas can disperse some oxidizing gas and reduce the decarburization phenomenon of the spiral pipe.