304不锈钢在含硼和锂的高温水中的应力腐蚀破裂和断口分析

FRACTOGRAPHY OF THE STRESS CORROSION CRACKING SPECIMENS OF TYPE 304 STAINLESS STEEL IN HIGH TEMPERATURE WATER CONTAINING BORIC ACID AND LITHIUM ION

采用高温高压慢应变速率拉伸试验方法 ,考察 30 4奥氏体不锈钢在含B和Li离子的介质中的应力腐蚀敏感性 .结果显示 ,材料的处理方式、介质中含Cl及试验温度均影响该钢种的应力腐蚀破裂敏感性 ,并在断口形貌中得以反映 .

Stress corrosion cracking (SCC) of 304 strainless steel in high temperature water media containing H 3BO 3 and Li + was studied using slow strain rate test (SSRT).One group samples were annealed (heated at 1050℃ for 60 min.then water quenched) and the other group samples were sensitized (annealed sample then heated at 650℃ for 120 min.and water quenched).Temperature for SSRT is 300℃ or 250℃.Water media contained 1200 mg/L H 3BO 3,2 mg/L Li +,2.5 mg/L or 5 mg/L Cl - in order to simulate pressurized water reactor condition.The results proved that sensitized material,chloride concentration in the water and higher test temperature showed SCC susceptibility more severely for 304 stainless steel.The fractography proved susceptibility clearly.