ABSTRACT In this, a method to measure welding residual stress in butt-welded joints of carbon steel plates using longitudinal critically refracted wave (Lcr wave) is proposed. Cross-correlation was employed to calculate the difference in time of flight between Lcr wave, and the optimal step length for the measurements is discussed. To determine Lcr wave acoustoelastic coefficient of the heat affected zone (HAZ), the relationship between the Lcr wave acoustoelastic coefficient and the grain size is established. The results show that one cycle is the optimal step length for the difference in the time-of-flight calculation, and with increasing grain size increase, Lcr wave acoustoelastic coefficient decreases in the form of a power function. In addition, grain size can be determined by using amplitude of the Lcr wave, so that the measured value of welding residual stress in HAZ can be corrected. The welding residual stress in melted zone (MZ) is corrected by calibrating acoustoelastic coefficient of the MZ. The acoustoelastic coefficient of the MZ is larger than that of parent material (PM). At last, welding residual stress in the butt-weld joint is measured and corrected with the Lcr wave technique. The results are verified by the hole drilling method.

中文翻译：

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利用纵波临界折射测量碳钢板焊接残余应力的晶粒尺寸校正

摘要 在此，提出了一种利用纵向临界折射波（Lcr 波）测量碳钢板对接焊缝焊接残余应力的方法。使用互相关来计算 Lcr 波之间的飞行时间差异，并讨论了测量的最佳步长。为了确定热影响区（HAZ）的Lcr波声弹性系数，建立了Lcr波声弹性系数与晶粒尺寸之间的关系。结果表明，一个周期是飞行时间计算差异的最佳步长，随着晶粒尺寸的增加，Lcr波声弹性系数以幂函数的形式减小。此外，可以通过使用 Lcr 波的振幅来确定晶粒尺寸，从而可以校正热影响区焊接残余应力的测量值。通过校准MZ的声弹性系数来校正熔化区（MZ）的焊接残余应力。MZ 的声弹性系数大于母材 (PM) 的声弹性系数。最后，采用Lcr波技术对对接焊缝的焊接残余应力进行测量和校正。结果通过钻孔方法验证。