pH值对高温高压水中304L不锈钢应力腐蚀开裂的影响

Effects of pH values on the stress corrosion cracking of 304L stainless steel in high-temperature and high-pressure water

在高温高压水环境中,采用慢应变速率拉伸试验方法,研究了不同pH值对304L不锈钢应力腐蚀开裂行为的影响规律,并通过扫描电镜对试样断口形貌进行观察与分析.结果表明:在300℃时,304L不锈钢在弱酸性和弱碱性溶液中的应力腐蚀开裂敏感性较大,且酸性越强,敏感性越大.在中性溶液中,304L不锈钢的强度和塑性损失较小,应力腐蚀敏感性较小,断口分析与之吻合.

The effects of pH values on the stress corrosion cracking（SCC）of 304L stainless steel in high-temperature and high-pressure water were studied using slow strain rate tension（SSRT）tests.The fracture morphology of SCC specimens was analyzed with the aid of scanning electron microscopy（SEM）.It is shown that 304L stainless steel exhibits a high susceptibility to SCC in weak alkaline and acidic solutions at 300 ℃,and the susceptibility increases by decreasing the pH value of the solution.In neutral solutions,both the strength and toughness of 304L stainless steel display a limited loss,indicating that 304L stainless steel has a low susceptibility to SCC.Fractography analysis is also consistent with these conclusions.