440A 스테인리스강의 입계부식에 미치는 첨가원소와 열처리의 영향

Abstract

440A martensitic stainless steels which were modified with reduced carbon content(~0.5wt.%) and addition of small amount of vanadium, tungsten and molybdenum 0.4wt.%, 0.4wt.% and 0.68wt.% respectively were manufactured. Effects of alloying elements and tempering temperatures on the intergranular corrosion were investigated through the method of DL-EPR(Double-electrochemical potentiodynamic reactivation).

(1) The highest DOS(Degree of sensitization)% of specimens was obtained at the tempering temperature of 450℃ regardless of types of alloy because of the precipitation of Cr7C3 (2) Addition of vanadium lowered DOS% a little above the tempering temperature of 550℃. It was considered to be effected by precipitation of VC carbides. (3) Intergranular corrosion was influenced more by tempering temperature than by alloying elements of V, W and Mo.