Heat Treatment Process Of Seamless Steel Tube Corrosion-resistant Steel

Seamless steel pipes are required to have excellent wear resistance, machinability, heat resistance, and high strength and toughness of thick walled seamless steel pipes. In addition, some seamless steel pipes may decompose gases such as hydrogen chloride, hydrogen fluoride, and sulphur dioxide in a molten state, so the mould must have a certain degree of corrosion resistance. At present, domestic seamless steel pipe users generally choose 4Cr13 stainless steel.

This study investigated the hardness and microstructure of two types of seamless steel pipes after quenching and tempering at different temperatures, and compared the polishing performance and corrosion resistance of the two steels under usage conditions. The results indicate that:

(1) After appropriate heat treatment, both types of seamless steel pipes have relatively high hardness. The quenching and tempering hardness of B steel is higher than that of A steel, but both can meet the requirements of seamless steel pipe molds.

(2) Based on the experimental results and the material requirements of the mould, it is recommended to use a heat treatment process of 1040 ℃ oil quenching and 610 ℃ double tempering.

(3) Under the same conditions and in the same state, the polishing performance of B steel is superior to that of A steel.

(4) Under the same quenching and tempering process and corrosion conditions, the corrosion resistance of B steel is superior to that of A steel, with an average annual corrosion depth reduced by 34.28% compared to A.