激光冲击对X80管线钢焊接接头应力腐蚀的影响

Effects of Laser Shock Processing on Stress Corrosion of X80 Pipeline Steel Welded Joints

摘要:

利用激光冲击波对X80管线钢焊接接头进行了表面改性处理，通过慢拉伸试验分析了X80管线钢焊接接头在NACE溶液（不含H2S和含饱和H2S）的H2S应力腐蚀开裂(SCC)行为，研究了经激光冲击处理后焊接接头表面细化的晶粒和残余应力对H2S应力腐蚀的影响机理.结果表明：激光冲击处理可改善焊接接头的表面质量，形成强化层，产生晶粒细化和残余压应力，获得细小均匀的针状铁素体组织，因大量晶粒承受氢压，可显著提高材料的临界应力值。应力腐蚀敏感指数ISCC比原始状态下降了5.84%，提高了X80管线钢焊接接头抗SCC的性能.激光冲击处理使X80管线钢焊接接头表面粗糙度有所上升，在一定程度上又降低了X80管线钢焊接接头SCC抗力.

Abstract:

Surface of X80 pipeline steel welded joint was processed by laser shock processing, and H2S stress corrosion cracking (SCC) behaviors of X80 pipeline steel welded joints in NACE solution (without H2S) and NACE solution (saturated H2S) were analyzed with slow strain rate testing (SSRT). The mechanism of refined grains and compressive residual stress of X80 pipeline steel welded joints by laser shock processing on H2S stress corrosion was investigated. The experimental results show that surface qualities of the welded joints are improved by laser shock process, and the strengthened layer is formed, which make the refined grain and compressive residual stress on the surface of X80 pipeline steel welded joints. The hydrogen compress is endured by the large number of grains to obviously increase its critical stress value. The sensibility index of stress corrosion ISCC by laser shock processing is decreased by 5.84% as compared to that in primitive state with the result that its properties of resistance SCC were improved. The surface roughness of X80 pipeline steel welded joint is increased by laser shock processing, and the SCC resistance of X80 pipeline steel welded joint is reduced to a certain extent.