高残余应力下2507双相不锈钢应力腐蚀开裂行为

Stress Corrosion Cracking Behavior of 2507 Duplex Stainless Steel under High Residual Stress

应用宏观、无损、金相、α相测定、断口、能谱等试验方法,对高残余应力下2507双相不锈钢Cl-应力腐蚀裂纹特征、路径、成因等进行分析。结果表明,双相不锈钢构件只有在特定的条件下(较低的应力水平、较低的温度、含有Cl-的中性溶液中),其突出的抗Cl-应力腐蚀开裂性能才能充分显现。上述条件有一个被突破,特别是高应力下(如厚件大面积堆焊所产生的大范围、高峰值残余应力),即使像2507这样的超级双相不锈钢,其抗应力腐蚀开裂的能力也将严重降低。该项工作对双相不锈钢的应用和结构制造具有一定参考价值。

By means of macroscopical examination,nondestructive testing,metallographic testing,α-phase measurement,fracture and energy spectrum,etc.,the characteristics,paths and causes of Cl-stress corrosion cracks of 2507 duplex stainless steel under high residual stress were analyzed.The results show that only under specific conditions(lower stress level,lower temperature,neutral solution containing Cl-)can the outstanding resistance of the duplex stainless steel to Cl-stress corrosion crack fully exhibit.One of the above conditions has been broken through,especially under high stress(e.g.,the large range and high peak residual stress caused by large area surfacing of thick components),even for super duplex stainless steel such as 2507,its stress corrosion cracking resistance will be seriously reduced.This work has certain reference value for the application and structure manufacture of duplex stainless steel.