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利用电子背散射衍射(EBSD)和显微硬度(HV)测量技术,表征了原始态、锻造固溶处理态和锻造去应力处理态316LN不锈钢(316LNSS)的显微组织和残余应变.利用U型弯曲应力腐蚀评价方法,研究了3种材料在325℃,3.5%Na OH溶液中的应力腐蚀开裂(SCC)行为的差异.结果表明,原始态316LNSS的SCC数量最多,裂纹扩展速率最大,而锻造固溶处理态316LNSS的SCC敏感性最低;原始态和锻造固溶处理态的316LNSS在高温碱性溶液中发生明显的沿晶应力腐蚀开裂(IGSCC),而锻造去应力态的316LNSS发生混合型SCC;去应力处理不能有效消除锻造过程中可能产生的条带组织,不利于316LNSS整体抗SCC性能的提高.
The microstructure and residual strain of 316LN stainless steel (316LNSS) were characterized by EBSD and HV measurement in the original state, the forged solution treated state and the forged as-quenched state, The stress corrosion cracking (SCC) behavior of the three materials in 3.5% NaOH solution at 325 ℃ was studied.The results show that the SCC number of the original 316LNSS is the largest and the crack propagation rate is the largest, while the forging 316LNSS in the solution treated state has the lowest susceptibility to SCC; 316LNSS in the original state and the as-forged solution treated state show obvious intergranular stress corrosion cracking (IGSCC) in the high temperature alkaline solution, while 316LNSS in forged de-stressed state undergo mixed SCC The stress-relieving treatment can not effectively eliminate the possible bands in forging process, which is not conducive to the improvement of the overall anti-SCC performance of 316LNSS.