超声冲击处理焊接接头疲劳设计若干问题的探讨  

DISCUSSION ABOUT IMPROVING FATIGUE PERFORMANCE OF WELDED JOINT BY ULTRASONIC PEENING

作　　者：王东坡[1] 田瑞莹[1] 霍立兴[1] 张玉凤[1] 王婷[1] 

机构地区：[1]天津大学材料科学与工程学院,天津300072

出　　处：《机械工程学报》2006年第11期173-178,共6页Journal of Mechanical Engineering

基　　金：国家自然科学基金(50405019)

摘　　要：对大量超声冲击处理焊接接头的试验结果进行分析总结,探讨超声冲击焊接接头疲劳设计与原始焊接接头的差异,并得到下述结论：①材料强度对超声冲击方法改善焊接接头疲劳性能的处理效果有一定影响,随着接头材料强度的提高改善效果也越好,因此采用低强钢超声冲击处理焊接接头的疲劳试验结果得到疲劳设计S—N曲线是安全的。②超声冲击处理焊接接头试件S—N曲线的斜率m远大于3(6～23),不能将试验结果硬性规定按m=3．0进行统计处理,推荐取m=10。③经过超声冲击处理后其疲劳强度不再与所外加的平均应力无关,而是随着应力比R的增加,接头所能够承受的疲劳应力幅度有所降低。因此建议采用最大应力对超声冲击处理焊接接头进行疲劳设计。④当采用最大应力对超声冲击处理焊接接头进行疲劳设计时,外载荷中所含平均应力与超声冲击处理焊接接头在FAT(200万次循环次数下的特定疲劳强度,将其定为疲劳级FAT)下的疲劳强度(应力范围)之间．的关系为：F(R)=1．25-0．5R,-1≤R≤0．5。Large number of testing results of the welded joints treated by ultrasonic peening are analyzed and summarized. Difference in fatigue design between as welded joints and joints treated by ultrasonic peening are discussed. The conclusions are ① Material strength has influence, to a certain extent, on the treatment effect on fatigue performance of welded joints treated by ultrasonic peening. As the material strength increases, the treatment effect will be better. Consequently, it is safe to use the fatigue design S--N curves gained from the fatigue testing results of the low strength steel. ② The S--N curves＇ slope m of welded joints treated by ultrasonic peening are much bigger than 3.0 （the sampling range is 6-23）. It is not appropriate to regulate forcedly that the statistics should be processed accord- ing to m=3.0, while 10 is recommended. ③ Aider the treat- ment of ultrasonic peening, the fatigue strength has something to do with the mean stress. Fatigue stress range that joints can support will decrease as the stress ratio R increases. Hence, it is suggested that the maximum stress should be used in the fatigue design of the welded joints treated by ultrasonic peening. ④ When the fatigue design of the welded joints treated by ultrasonic peening is processed using the maximum stress, the relationship between the mean stress of the applied load and the fatigue stress FAT of the welded joints treated by ultrasonic peening is： F（R） = 1.25 - 0.5R, -1 ≤R≤0.5.

关 键 词：超声冲击 焊接接头 平均应力 疲劳设计 材料强度 

分 类 号：TG404[金属学及工艺—焊接]