锻后热处理对核级316LN不锈钢在沸腾MgCl_2溶液中应力腐蚀行为的影响  

Effect of Post-forging Heat Treatment on Stress Corrosion Cracking of Nuclear Grade 316LN Stainless Steel in Boiling MgCl_2 Solution

作　　者：郭跃岭 韩恩厚[1,2] 王俭秋[1] 

机构地区：[1]中国科学院金属研究所中国科学院核用材料与安全评价重点实验室,沈阳110016 [2]北京科技大学国家材料服役安全科学中心,北京100083

出　　处：《中国腐蚀与防护学报》2015年第6期488-495,共8页Journal of Chinese Society For Corrosion and Protection

基　　金：国家科技重大专项项目(2011ZX06004-009)资助

摘　　要：研究了锻后固溶处理和锻后去应力处理对核电主管道用316LN不锈钢的显微组织、残余应变和常温力学性能的影响,并研究了不同锻后热处理工艺对316LN不锈钢在沸腾的42%(质量分数)Mg Cl2溶液中应力腐蚀开裂(SCC)敏感性的影响。结果表明,固溶处理能够降低材料的屈服强度和消除锻造过程中的残余应变;锻后固溶处理和锻后去应力处理的样品分别在沸腾Mg Cl2溶液中浸泡24,48和72 h后均发生明显的穿晶应力腐蚀开裂(TGSCC);浸泡72 h后,锻后去应力处理的样品已经完全开裂,而锻后固溶处理的样品只有部分区域发生SCC开裂,即SCC敏感性较低。最后从屈服强度和残余应变角度讨论了锻后热处理对不锈钢SCC敏感性的影响机制。Effect of post solution- and stress relief-treatment on the stress corrosion cracking （SCC） resistance via U-bend specimens test in 42% boiling MgC12 solution, as well as the micro- structure, 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 MgC12 solution for 24, 48 and 72 h, respectively, all the U-bend specimens of either the solution-treated or the stress relief- treated 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 spec- imens 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 treatments on the SCC resistance was discussed in terms of the residual strain and yield stress of the forged steel.

关 键 词：不锈钢 核电材料 热处理 应力腐蚀开裂 MgCl2溶液 断口 

分 类 号：TG171[金属学及工艺—金属表面处理]