超声波冲击与TIG熔修复合强化改善高强钢焊接接头的疲劳性能

研究表明超声波冲击方法与TIG熔修方法在提高焊接接头疲劳性能机理方面存在着很强的互补性。提出一种对接头焊趾先进行一遍TIG熔修处理,然后再实施超声波冲击的复合处理新方法用来改善焊接接头的疲劳性能。对比疲劳试验结果显示:①在一定的应力范围内,超声波冲击处理试件与原始焊态试件相比,疲劳强度提高95％左右,疲劳寿命延长3.6-62倍。②TIG熔修试件与原始焊态试件相比,疲劳强度的改善程度高达34％左右;在较高应力范围内,疲劳寿命没有提高:在低应力范围内,延长疲劳寿命约为0.4—1.3倍。③超声波冲击+TIG熔修复合强化试件与原始焊态试件相比,疲劳强度提高120％左右,疲劳寿命延长28—125倍。④TIG熔修+超声波冲击复合处理能够在TIG熔修和超声波冲击处理的基础上,进一步改善焊接接头的疲劳性能;与单纯的超声波冲击相比,在高应力区域内,TIG熔修+超声波冲击复合处理一定程度上克服了单纯的超声波冲击对所处理的焊接接头疲劳性能改善程度大幅度降低的缺点。

IMPROVING FATIGUE BEHAVIOR OF THE HIGH-STRENGTH WELDED JOINTS COMPOUND TREATED BY TIG DRESSING AND ULTRASONIC PEENING

Studies show that considering the mechanism of improving the fatigue performance, ultrasonic peening and TIG dressing are complementary. A new compound treating method of improving fatigue performance of high-strength welded joint is that firstly treated the welded toe by TIG-dressing and then performed ultrasonic peening. Test results indicated that: (1) In the given range of stress level, contrasted with the specimens in as welded condition the fatigue strength of the specimens treated by ultrasonic peening is increased by about 95% and the fatigue life is prolonged by 3.6-62 times. The fatigue strength of the specimens treated by TIG-dressing is increased by about 34% and the fatigue life is prolonged by 0.4-1.3 times. And while the fatigue strength of the specimens treated by compound treating by TIG-dressing adding ultrasonic peening is increased by about 120% and the fatigue life is prolonged by 28-125 times. (2) The fatigue strength can be even improved by compound treating ultrasonic peening adding TIG dressing on the basis of ultrasonic peening or TIG dressing. In the range of high stress, contrasted with simple ultrasonic peening treating TIG dressing adding ultrasonic peening compound treating has definitive predominance because compound treating overcome the decreasing of fatigue performance improvement of welded joint treated by simple ultrasonic peening.