摘要
采用慢应变速率试验(SSRT)方法,研究了电极电位和应变速率对低合金钢-不锈钢异材焊接件16MND5/309L/308L在模拟压水堆一回路高温水环境中应力腐蚀破裂(SCC)的影响。结果表明:在5×10-7 s-1应变速率条件下,在-720^+100mV(相对于标准氢电极SHE,下同)的低电位区,所有SSRT试样均在远离界面的308L焊缝金属区发生纯力学韧性断裂,与在氮气中的试验结果类似;当外加电位提高到+200mV后,试样在16MND5/309L界面发生SCC脆断,界面附近的16MND5侧发生穿晶SCC,309L侧发生沿晶SCC。该异材焊接件在该高温水环境中存在一个临界破裂电位,高于此电位发生SCC,在5×10-7s-1的应变速率下,该临界破裂电位处于+100^+200mV;降低速应变率至1×10-7s-1,临界破裂电位仍处于+100^+200mV;提高应变速率至1×10-6s-1后,在+200^+300mV电位区也没有显示出SCC。
Effects of electrode potential and strain rate on the stress corrosion cracking(SCC)behavior of dissimilar metal weld 16MND5/309L/308 Lin simulated primary water environment of pressurized water reactor(PWR)were investigated by means of slow strain rate testing(SSRT).Results showed that at strain rate of 5×10-7s-1,the SSRT specimens always failed in the bulk zone of stainless steel 308 L weld metal with ductile appearance when tested in the potential range from-720 mV to+100mV(vs.SHE).When electrode potential was raised to +200mV,SCC happened in the 16MND5/309 Linterface area,with transgranular SCC in low alloy steel 16MND5 zone close to the interface,intergranular SCC in the 309 Lweld metal close to the interface.There was a critical cracking potential above which SCC occurred,within the range from +100mV to+200mV for the dissimilar metal weld when tested at the strain rate of 5×10-7s-1 in simulated primary water environment of PWR.When strain rate was decreased to1×10-7s-1,the critical cracking potential was still within the range from +100mV to +200mV although the test time increased significantly.When strain rate was raised to 1×10-6s-1,SCC was not observed even at the potentials+200mV and +300mV.
出处
《腐蚀与防护》
CAS
北大核心
2015年第10期923-928,共6页
Corrosion & Protection
基金
国家重点基础研究发展计划(2011CB610506)
关键词
压水堆核电站
异材焊接件
一回路高温水
应力腐蚀破裂
电极电位
应变速率
pressurized water reactor
dissimilar metal weld
primary water
stress corrosion cracking
electrode potential
strain rate