超声冲击法提高焊接接头疲劳特性研究进展

摘要

焊接结构的失效以疲劳断裂为主，且焊接结构强度主要是由焊接接头的疲劳强度决定的。因此，改善焊接接头疲劳性能将显著提高焊接结构的整体性能。超声冲击处理是一种有效改善焊接接头疲劳性能的表面强化技术。研究表明，该技术通过改善焊接接头几何外形，细化表层晶粒及引入有益残余压应力可大幅度提高焊接接头的疲劳强度和疲劳寿命。综述了超声冲击处理对焊接接头疲劳性能影响的研究现状，分析了影响焊接接头疲劳性能的因素，总结了超声冲击改善焊接接头疲劳性能的结果，对目前研究过程中存在的问题进行探讨，最后展望了超声冲击表面纳米化技术的应用前景。%Fatigue fracture is the main failure mode of welded structures,and the welded structures′fatigue strength is primarily determined by welded joints.Therefore,improving the fatigue performance of welded joints will greatly promote the total performance of the welded structure.Ultrasonic impact treatment (UIT)is an effective tech-nique to improve the fatigue performance of welded joints.Studies have shown that this technique can greatly improve the welded joints′strength and fatigue life by improving the welded joints geometry,refining surface grain and intro-ducing the beneficial residual compressive stress.The effects of UIT on the fatigue properties of welded joints are de-scribed in this paper,the factors which influence the fatigue performance of welded joints are also analyzed.In addi-tion,the fatigue performance results of welded joints after UIT are summarized.Finally,problems which exist in cur-rent research and application prospect of the surface nanocrystallization by UIT are discussed.