Cold Work-caused Detriment of Corrosion Resistance of Stainless Steel Tube and Preventative Controls

Analyzed here in the article are the reasons for and elements related to cold work-caused detriment of corrosion resistance of the stainless steel tube. The necessity of solution or annealing heat treatment for the seamless stainless steel tube is emphasized， while the wrong understanding is corrected that corrosion resistance and heat resistance of the seamless stainless steel tube is certainly better than those of the weld steel tube. The importance of properly controlling of the material’s deformation amount during cold working process，and control principles and methods that based on applicable standards of Europe and America are introduced， including decision-making concerning whether stress-relief heat treatment is needed or not，the heat treatment methods，and a newly-developed structure of heat-exchanger composed of twisted tubes.