Research and Development > Technical Report > No.12 Special Issue on “Steel Pipes and Tubes” and “Stainless Steel” > Mo-Saving Stainless Steel JFE 445M for Hot Water Tanks

No.12 Special Issue on “Steel Pipes and Tubes” and “Stainless Steel”

Mo-Saving Stainless Steel JFE 445M for Hot Water Tanks

FUKUDA Kunio     ISHIKAWA Shin     KASAMO Toshihiro

Abstract

For the use of hot water tank, JFE Steel developed the cost-saving JFE445M (22.5mass%Cr-1mass%Mo) stainless steel containing less Mo than the current material Type444 (19mass%Cr-2mass%Mo) stainless steels. The results of corrosion tests, such as the pitting potential, the rate of rusted area at cyclic corrosion test, the repassivation potential for crevice corrosion, indicated JFE445M had the same or even better corrosion resistance than Type444. At the welding zone by Tungsten Inert Gas (TIG) welding method, JFE445M exhibited particularly higher corrosion resistance than Type444. It was considered that the higher Cr content of JFE445M prevented the severe Cr depletion at the interface between the scale and the substrate when the oxide layer was formed during welding.

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