激光冲击波对X80管线钢焊接接头疲劳性能的影响  

Effects of laser shock wave on fatigue properties of X80 pipeline steel welded joints

作　　者：孔德军[1] 龙丹[1] 叶存冬[1] 王文昌[2] 吴永忠[1] 

机构地区：[1]常州大学机械工程学院,江苏常州213016 [2]常州大学石油化工学院,江苏常州213164

出　　处：《材料热处理学报》2014年第1期103-108,共6页Transactions of Materials and Heat Treatment

基　　金：江苏省自然科学基金(BK2009104);江苏省普通高校研究生科研创新计划项目(CXLX11-0388;CXZZ12-731);江苏省科协首席专家(工程师)项目

摘　　要：利用激光冲击波对X80管线钢焊接接头进行了表面强化处理,通过拉伸疲劳对比试验,采用罗卡提法求出激光冲击强化处理前后X80管线钢焊接接头的疲劳极限。用扫描电镜和X射线衍射仪分析了激光冲击处理前后X80管线钢焊接接头断口形貌和残余应力,并对激光冲击处理提高抗疲劳断裂机理进行探讨。结果表明,激光冲击处理引入了-339 MPa的残余压应力,使X80管线钢焊接接头疲劳强度由445 MPa提高到496 MPa,提高了11.2%;原始状态的试样疲劳裂纹起始于试样表面,经激光冲击处理后焊接接头疲劳源转移至次表层,表层晶粒细化和残余压应力是主要机制,提高了X80管线钢焊接接头的疲劳性能。Surface of XS0 pipeline steel welded joint was processed with LSP （laser shock processing）, the fatigue limits of X80 pipeline steel welded joints before and after LSP were obtained by tension fatigue experiments based on Locati method. The fracture morphology and residual stress of X80 pipeline steel welded joint before and after LSP were analyzed by SEM and XRD, respectively. The mechanism of improving fatigue fracture resistance by LSP was discussed. The results show that the compressive residual stress of - 339 MPa is introduced by LSP, increasing fatigue strength of X80 pipeline steel welded joint by 11. 2% , from 445 MPa to 496 MPa. The fatigue crack of the as-received specimen in primitive state is initiated at the surface, while the fatigue crack is initiated in subsurface for the specimen after LSP. The surface grain refinement and compressive residual stress of the welded joint by LSP is the main mechanism for the improvement of fatigue properties of the X80 pipeline steel welded joints.

关 键 词：激光冲击处理 X80管线钢 焊接接头 疲劳性能 断口形貌 

分 类 号：TG142.4[一般工业技术—材料科学与工程]