变幅载荷下超声冲击处理焊接接头的疲劳行为

为研究变幅载荷作用下超声冲击处理焊接接头的疲劳行为，采用非承载纵向角接接头进行了Q235B及16Mn钢原始焊态与超声冲击处理态的对比疲劳试验。试验结果表明：①在变幅载荷作用下，Q235B超声冲击处理试件与原始焊态试件相比，疲劳强度提高69%左右，疲劳寿命延长5.7～19.0倍。②在变幅载荷作用下，16Mn超声冲击处理试件与原始焊态试件相比，疲劳强度提高80%左右，疲劳寿命延长2.5～17.0倍。③在变幅载荷作用下，超声冲击处理焊接接头与原始焊态试件的疲劳性能均有所下降：Q235B超声冲击处理焊接接头的疲劳寿命约为恒幅载荷作用时的1/3，原始焊态的疲劳寿命约为恒幅载荷作用时的70%；16Mn超声冲击处理焊接接头的疲劳寿命约为恒幅载荷作用时的1/3，原始焊态的疲劳寿命约为恒幅载荷作用时的75%。④超声冲击处理焊接接头在承受强烈的变幅载荷时依然具有很高的疲劳强度。

FATIGUE BEHAVIOR OF THE WELDED JOINTS TREATED BY ULTRASONIC PEENING UNDER VARIABLE-AMPLITUDE LOAD

In order to research the fatigue behavior of the welded joints treated by ultrasonic peening under variable-amplitude load, the fatigue contrast tests of Q235B and 16Mn steel welded joints in two different states(ultrasonic peening and as welded condition)are directed. Test results show that: (1)When acted by variable amplitude load, contrasted with the Q235B steel specimen in as welded condition the fatigue strength of the specimen treated by ultrasonic peening is increased by about 69% and the fatigue life is prolonged by 5.7-19.0 times. (2)When acted by variable amplitude load, contrasted with the specimen in as welded condition the fatigue strength of the specimen treated by ultrasonic peening is increased by about 80% and the fatigue life is prolonged by 2.5~17.0 times. (3)Acted by variable amplitude load, the fatigue performance of the welded joints treated by ultrasonic peening or as welded is inferior to that of the welded joints which acted by constant amplitude loads. The fatigue life of the Q235B steel welded joints treated by ultrasonic peening is one third of that of the welded joints acted by constant amplitude loads. The fatigue life of as welded joints is about 70% of that of the welded joints acted by constant amplitude loads. The fatigue life of the 16Mn steel welded joints treated by ultrasonic peening is about one third of that of the welded joints acted by constant amplitude loads. The fatigue life of as welded joint is about 75% of that of the welded joints acted by constant amplitude loads. (4)Fatigue strength of welded joints that treated by ultrasonic peening still maintains high when acted variable amplitude loading.