주조용 CD4MCU 이상 스테인리스강의 크롬 함량에 따른 인장 및 부식 거동 = Tensile and Corrosion Behavior of Cast CD4MCU Duplex Stainless Steel with Different Chromium Contents

다국어 초록 (Multilingual Abstract)

The effect of chromium contents on the microstructure, tensile and corrosion behaviors of as-solutionized CD4MCU(Fe-25Cr-5Ni-2.8Cu-2Mo) cast duplex stainless steel was examined in the present study. The slow strain rate test was also conducted at a nominal strain rate of 1×10^-6/sec in air and 3.5% NaCl+5% H_2SO_4 solution for studying the stress corrosion cracking behavior of the present alloy. It was observed that the increasing amount of chromium encouraged the precipitation of fine 2nd austenitic phases in the ferritic matrix. The fine austenitic phases appeared to contribute the homogenization of deformation, and, consequently, the ultimate tensile strength and elongation were largely improved. The resistance to general and pitting corrosion of CD4MCU alloys in 3.5% NaCl+5% H_2SO_4 solution was significantly improved with the addition of chromium. The trend observed in the stress corrosion cracking(SCC) behavior of CD4MCU alloys in 3.5% NaCl+5% H_2SO_4 solution with different chromium contents was two-fold. In the anodic dissolution environment, the higher chromium content was beneficial in improving the SCC resistance. The reverse was true in the hydrogen generating environment.