公路斜拉桥中焊接残余应力的减小与消除的探析

公路斜拉桥锚拉板的焊接残余应力对锚拉板的疲劳寿命产生直接影响,对斜拉桥的使用寿命起决定作用,因此研究如何减小和消除公路斜拉桥锚拉板焊接残余应力具有重要意义。运用超声冲击设备,对斜拉桥锚拉板适用Q370qe钢材焊接热影响区实施超声冲击试验,采用盲孔法检测超声冲击前后热影响区的应力,通过探讨热影响区焊接残余应力在不同超声冲击处理工艺下产生的改变,并分析其规律,继而为斜拉桥锚拉板的生产制造提供有效建议。试验结果表明,超声冲击处理可以把Q370qe钢板焊接残余拉应力转变成压应力,对斜拉桥锚拉板焊接残余应力的减小和消除有比较好的成效;在冲击时间不变的情况下,增加冲击电流可以增大冲击力,使得残余应力焊接热影响区塑性变形和位错结构改变增大,继而消减率随之增加,但是增加的速度减缓;在冲击电流不变的情况下,冲击时间增加,消减率没有显著的变化规律。

Analysis on the Reducing and Eliminating Welding Residual Stress in Highway Cable-stayed Bridge

The welding residual stress of the anchor plate of the highway cable-stayed bridge has a direct influence on the fatigue life of the anchor plate,and plays a decisive role in the service life of the cable-stayed bridge.Therefore,it is of great significance to study how to reduce and eliminate the residual stress of the anchor plate of the highway cable-stayed bridge.The ultrasonic impact test is applied to the anchor plate of the cable-stayed bridge by using the ultrasonic impact equipment,and the ultrasonic impact test is carried out on the welding heat-affected area of the anchor plate of the cable-stayed bridge by using the blind hole method,The changes of the welding residual stress in the heat-affected zone under different ultrasonic impact treatment processes are discussed,and the law of the welding residual stress is analyzed,and the effective suggestions are provided for the production and manufacture of the anchor plate of the cable-stayed bridge.The test results show that the ultrasonic impact treatment can transform the residual tensile stress of the Q370qe steel plate into compressive stress,and has better effect on the reduction and elimination of the residual stress of the anchor plate of the cable-stayed bridge;and under the condition that the impact time is not constant,the impact current can be increased,So that the plastic deformation of the residual stress welding heat affected zone and the change of the dislocation structure are increased,then the reduction rate is increased,but the speed of the increase is reduced;and under the condition of no change of the impact current,the impact time is increased,and the reduction rate does not change significantly.