声弹性法无损检测焊接残余应力

Measurement of welding residual stresses by acoustoelastic technique

本文介绍了声弹性理论基础和有关焊接残余应力超声测量仪,利用声弹性应力分析方法测量了焊接对接接头中残余应力的分布,这一工作是通过采用脉冲回波重合法,测出主方向偏振超声剪切波速度差完成的,并提出了一种估算材料各向异性的新方法,研究结果表明,焊缝金属区的各向异性系数比母材区各向异性系数大得多,由声弹性方法测得的纵向残余应力分布与理论计算结果吻合较好,其测量精度明显高于由电阻应变仪测量的结果.

In this paper the acoustoclasticity theory and an ultrasonic testing instrument for welding residual stress analysis arc described. The acoustoclasticity stress analysis was applied to measure welding residual stress distributions nondestructivcly in a welded joint. The technique of acoustoclastic stress analysis employed in this paper uses the velocity difference in ultrasonic chcar waves polarized in principal directions by means of the pulse echo overlap method. A new method to evaluate the material anisotropy is proposed. The results arc as follows: the material anisotropy of the weld metal is much stronger than that of the bacc metal; longitudinal residual stress distributions measured by the acoustoclastic technique arc coincident with those obtained by the theoretical analysis.