Effect of Post-forging Heat Treatment on Stress Corrosion Cracking of Nuclear Grade 316LN Stainless Steel in Boiling MgCl2 Solution

Abstract

s: Effect of post solutionand stress relieftreatment on the stress corrosion cracking (SCC) resistance via U-bend specimens test in 42% boiling MgCl2 solution, as well as the microstructure, residual strain and mechanical properties of the forged 316LN stainless steel was studied. Results showed that the yield stress was reduced and the residual strain was eliminated through post solution-treatment for the forged steel. After immersion in boiling MgCl2 solution for 24, 48 and 72 h, respectively, all the U-bend specimens of either the solution-treated or the stress relieftreated steels suffered from clearly transgranular stress corrosion cracking (TGSCC). Furthermore, of which all the stress relief-treated specimens were entirly cracked, while the solution-treated specimens were only locally cracked after immersion for 72 h, suggesting higher SCC resistance for the forged steel after a proper post solution-treatment. Finally, the mechanism of the effect of post-heat 定稿日期:2014-11-05 基金项目:国家科技重大专项项目 (2011ZX06004-009)资助 作者简介:郭跃岭,男,1990年生,硕士生 通讯作者:韩恩厚,E-mail:ehhan@imr.ac.cn,研究方向为苛刻环境中材料的腐蚀与防护 (核电高温高压水、石油化工环境等等) DOI:10.11902/1005.4537.2014.223 6期 郭跃岭等:锻后热处理对核级316LN不锈钢在沸腾MgCl2溶液中应力腐蚀行为的影响 treatments on the SCC resistance was discussed in terms of the residual strain and yield stress of the forged steel.