激光冲击对X70管线钢焊接接头H_2S应力腐蚀断口的影响  

Effects of laser shock processing on H_2S stress corrosion fractures of X70 pipeline steel welded joints

作　　者：孔德军[1] 吴永忠[1] 龙丹[1] 

机构地区：[1]常州大学机械工程学院,常州213016

出　　处：《焊接学报》2011年第10期13-16,113,共4页Transactions of The China Welding Institution

基　　金：江苏省自然科学基金资助项目(BK2009104);江苏省普通高校研究生科研创新计划项目(XM2011-388)

摘　　要：利用激光冲击波对X70管线钢焊接接头进行了改性处理,通过慢应变速率法(SSRT)研究了其在NACE(national association of corrosion engineers)标准饱和H2S溶液中应力腐蚀的敏感性,并对其断口进行SEM观察,分析了激光冲击处理对X70管线钢焊接接头抗H2S应力腐蚀开裂(SCC)行为的影响.结果表明,原始状态的X70管线钢焊接接头为脆性断裂,断口为应力腐蚀裂纹;经激光冲击处理后X70管线钢焊接接头,韧窝尺寸与深度变小,断口形式为韧性断裂;SCC是X70管线钢焊接接头应力腐蚀断裂的主要机制,激光冲击处理降低了氢致开裂和SCC的倾向,提高了焊接接头抗H2S应力腐蚀的能力.The surfaces of X70 pipeline steel welded joints were processed with laser shock and its stress corrosion sensitivity was investigated in NACE saturated H2S solutions by slow strain rate testing(SSRT).The fracture surfaces were analyzed with scanning electric microscope(SEM).The results show that the X70 pipeline steel welded joints in primitive state is brittle fracture.The cracks of tensile fracture is stress corrosion cracking.The mechanical properties of the X70 pipeline steel welded joints after laser shock processing is enhanced,its dimple dimension and depth becomes smaller,and the fracture mode is ductile fracture.SCC is the main mechanism of X70 pipeline steel welded joint stress corrosion cracking.Laser shock processing reduces the tendency of SCC and improves stress corrosion resistance H2S of the welded joint.

关 键 词：X70管线钢 焊接接头 激光冲击处理 应力腐蚀 

分 类 号：TG115.28[金属学及工艺—物理冶金]