45 Seamless Steel Pipe

Comparison and Analysis of Heat Treatment for Corrosion-Resistant Seamless Steel Tubes

Seamless steel tubes must possess excellent wear resistance, machinability, heat resistance, and high strength and toughness for thick-walled tubes. Additionally, as some seamless steel tubes may release gases such as hydrogen chloride, hydrogen fluoride, and sulfur dioxide during the molten state, the molds must have certain corrosion resistance. Currently, domestic users of seamless steel tubes generally choose 4Cr13 stainless steel.

This study investigated the hardness and microstructure of two seamless steel pipes after different temperature quenching and tempering processes. A comparative analysis was conducted on the polishing properties of the two steels, as well as their corrosion resistance under service conditions. The results indicate:

(1) Both types of seamless steel tubes have relatively high hardness after proper heat treatment. The quenching and tempering hardness of B steel is higher than that of A steel, yet both meet the requirements for seamless tube molds.

(2) Based on the experimental results and the material requirements of the mold, recommend the heat treatment process of oil quenching at 1040℃ followed by two tempering cycles at 610℃.

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

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