硫酸根离子和电极电位对异材焊接件A508/52M在高温水中应力腐蚀破裂的影响  

Effects of Sulfate and Electrode Potential on Stress Corrosion Cracking of A508/52M Dissimilar Metal Weld in High Temperature Water Environments

作　　者：王光辉[1] 彭君[1] 袁义帆[1] 李光福[1] 杨武[1] 

机构地区：[1]上海材料研究所上海市工程材料应用与评价重点试验室,上海200437

出　　处：《理化检验（物理分册）》2013年第6期357-361,366,共6页Physical Testing and Chemical Analysis(Part A:Physical Testing)

基　　金：国家重点基础研究发展计划资助项目(2011CB610506);核电重大专项资助项目(2010ZX06004-009-03)

摘　　要：采用慢应变速率拉伸(SSRT)、电位测控和水中掺杂的方法,研究了SO_4^(2-)和电极电位对异材焊接件A508/52M在模拟压水堆核电站主回路高温水环境中应力腐蚀破裂(SCC)行为的影响。结果表明:在有和无SO_4^(2-)掺杂的水环境中,试样SSRT的力学行为和断口形貌随电极电位变化的规律相似,即在低电位区均在远离界面的镍基合金焊缝处发生韧性断裂,与氮气环境中的拉伸试验结果相似;在高电位区,试样在焊接件界面周围区域发生SCC脆断;但掺杂10 g·m^(-3)的SO_4^(2-)后,试样发生SCC的临界电位明显降低,说明SO_4^(2-)的存在增加了该异材焊接件在主回路水中的SCC敏感性。最后探讨了相关试验现象的机理和该研究的工程意义。The effects of sulfate and electrode potential on stress corrosion cracking （SCC） behavior of A508/ 52M dissimilar metal weld in simulated primary water environments of pressurized water reactor （PWR） at 290 ℃ were investigated by means of slow strain rate tensile （SSRT） test and electrode potential control. The results show that the variations of SSRT behaviors with the electrode potential of the weld in the waters without and with sulfate doping were generally similar, that is, ductile failure in the bulk zone of Ni-based weld metal when tested at low potentials, but brittle failure by SCC in the area around the ASO8/52M interface when tested at high potentials. Doping 10 g · m 3 SO4^（2-） into the simulated primary water increased the SCC susceptibility by decreasing the critical potential for SCC. The cracking mechanism and the engineering practical significance were discussed at last.

关 键 词：压水堆核电站 主回路水 异材焊接件 应力腐蚀破裂 电极电位 硫酸根离子 

分 类 号：TG172[金属学及工艺—金属表面处理]