高温水中静荷重下におけるマルテンサイト系ステンレス鋼の応力腐食割れ挙動
1989 年 75 巻 8 号 p. 1338-1345
詳細
1989 年 75 巻 8 号 p. 1338-1345
Stress corrosion cracking behavior of martensitic stainless steels is evaluated as a function of tempering temperature by means of three points bending SCC tests in high purity water at 70-288°C. Stress corrosion cracking initiates at small corrosion pits or crevice corrosion and SCC susceptibility increases with increasing hardness of the steel. Threshold SCC stress is about 300 MPa for the steel with hardness of HV 430 and equal to yield strength for that of HV 300. No susceptibility is detected for the steels of which HV are less than 270 with an exception of the steel of high Ni content. SCC susceptibility increases with increasing water temperature and increasing hardness of steels. Chromium plated steel and high Ni steel show higher SCC susceptibility than the unplated steel and lower Ni steel, respectively. Low C and low Ni steel in fully annealed conditions exhibits no SCC susceptibility even in long term exposure test for 5 000h in high purity water at 288°C.
