溶解氧对高温水中冷变形316L应力腐蚀开裂的影响规律

SCC Crack Growth Rate Dependence of Cold Worked 316L Stainless Steel on Dissolved Oxygen in High Temperature Water

为研究冷变形不锈钢材料在不同溶解氧含量时的开裂规律,使用经冷弯变形的管道316L不锈钢在模拟压水堆一回路温度和压力的条件下进行实验.使用直流电压降法,原位在线测量材料在水中不同含氧量下的裂纹扩展速率.实验结果:材料的裂纹扩展速率随溶解氧含量的升高而升高.在含氧量小于0.2mg/L时这种变化趋势非常的显著,而当超过该值后,这种变化趋势变得缓慢.对这一现象产生的原因进行了分析.

The cold bent 316L pipe was used to study the dependence of crack growth rate on dissolved oxygen in simulated temperature and pressure of primary side water environment. The crack growth rates were measured in-situ real-time using the direct current potential drop method. Experimental results indicate that the crack growth rates increase with the increase of dissolved oxygen. When the oxygen content is less than 0.2 mg/L, the increase of the crack growth rate is very significant, while above this value, it becomes unconspicuous. This result was compared with those of other researchers＇ and possible reasons were analyzed.