How to prevent decarburization of thick wall spiral steel pipe

　　The service life of spiral steel pipe and its surface decarburization are positively related. If the surface decarbonization, the strength and wear resistance of spiral steel pipe will be reduced, which will directly affect the service life of spiral steel pipe. If the decarburization layer on the spiral pipe is not cleaned, the hardness and wear resistance of the surface layer of the spiral steel pipe will be reduced correspondingly. Moreover, during the quenching process, cracks will be formed on the surface of the workpiece due to the volume change of the inner and outer layers.

　　If you want to deal with the decarburization of the surface, if you want to deal with the heat treatment process, because decarburization and the oxidation of spiral steel pipe are carried out at the same time, therefore, in the process of heat treatment, we should not let the spiral steel pipe and air contact, so as to improve the decarburization phenomenon.

　　The medium forming decarburization on the surface of the spiral tube is mainly oxygen, steam and carbon dioxide. When these gases contact with the heated spiral tube, the oxidation and decarburization of the spiral tube will be formed. Therefore, the ratio of carbon dioxide to carbon monoxide in the tube furnace is also important.

　　Originally, adding protective gas nitrogen into the forging furnace of spiral steel pipe is also very useful. Nitrogen may be used to remove some oxidizing gas and reduce decarburization of spiral pipe.