超声冲击对十字焊接接头表面形貌及应力集中系数的影响

Effects of ultrasonic impact treatment on surface morphology and stress concentration coefficient of welded cross joint

用HJ-Ⅲ型超声冲击枪对转向架用SMA490BW钢十字焊接接头焊趾表面进行超声冲击处理;根据不同冲击参数获得的几何形貌建立相应的三维模型,再通过有限元软件Ansys计算不同冲击参数下的应力集中系数Kt;应用Origin软件拟合过渡圆弧半径、凹陷深度和应力集中系数与冲击时间的数据关系。结果表明:应力主要集中在十字焊接接头的焊趾凹陷处;应力集中系数Kt随焊趾过渡圆弧半径增大而减小,随凹陷深度的增加而增大;过渡圆弧半径、凹陷深度随冲击时间的增加先增大后趋于平缓;应力集中系数Kt随冲击时间的增加在0~5 min阶段下降较快后维持在1.85左右。

The weld toe surface of SMA490 BW steel welded cross joint of train bogie was treated by HJ-Ⅲ type ultrasonic impact machine. According to the geometrical morphology under different impact parameters,the corresponding 3 D model was built,the stress concentration factor Ktof different impact parameters was calculated through the finite element software Ansys. The diagrams of the transition arc radius,concave depth and stress concentration coefficient and impact time were fitted by Origin software. The results show that the stress concentrates at the cross weld toe hollow,the stress concentration factor Ktdecreases as the weld toe transition arc radius increases,and increases with the sunk depth. Transition arc radius and sunk depth increase with the prolongation of the impact time,then tend to increase gently. With impact time extension,the stress concentration factor Ktfalls faster in 0-5 min stage,then maintains 1.85 around.