Comparison Between Using Longitudinal and Shear Waves in Ultrasonic Stress Measurement to Investigate the Effect of Post-Weld Heat-Treatment on Welding Residual Stresses
Comparison Between Using Longitudinal and Shear Waves in Ultrasonic Stress Measurement to Investigate the Effect of Post-Weld Heat-Treatment on Welding Residual Stresses
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DOI：
10.1080/09349847.2015.1123786
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发表时间：
2017-04
影响因子：
1.4
通讯作者：
Y. Javadi;khaled azari;S. Ghalehbandi;M. Roy
中科院分区：
文献类型：
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作者：
Y. Javadi;khaled azari;S. Ghalehbandi;M. Roy
熔焊是工业上广泛应用的一种连接工艺。然而，一旦焊接过程完成，就会产生不希望的残余应力。为了消除焊接残余应力，焊后热处理（PWHT）被广泛采用。研究了PWHT时间和温度对铁素体不锈钢残余应力的影响。采用超声法测量了8个焊接试样的残余应力分布。超声应力测量是一种基于声弹性定律的无损测量方法，它将机械应力与超声波在被测材料内传播的速度联系起来。超声波可以是纵向（法向）或横向（剪切）换能器分别产生的纵波或横波。基于纵波的超声应力测量使用该方向的纵向临界折射（LCR）波，而横波方法使用超声双折射现象。结果表明，纵波法和横波法均能较好地推断出PWHT的作用，但横波法对应力变化更为敏感。此外，采用LCR方法可以更好地区分地下残余应力的分布。
ABSTARCT Fusion welding is a joining process widely used in the industry. However, undesired residual stresses are produced once the welding process is completed. Post-weld heat-treatment (PWHT) is extensively employed in order to relieve the welding residual stresses. In this study, effect of PWHT time and temperature on the residual stresses of a ferritic stainless steel is investigated. Residual stress distributions in eight welded specimens were measured by using an ultrasonic method. Ultrasonic stress measurement is a nondestructive method based on acoustoelasticity law, which correlates mechanical stresses with velocity of an ultrasonic wave propagating within the subject material. The ultrasonic wave employed could be longitudinal or shear wave produced by the longitudinal (normal) or transverse (shear) transducers, respectively. Ultrasonic stress measurements based on longitudinal waves use longitudinal critically refracted (LCR) waves in this direction, while shear wave methods use an ultrasonic birefringence phenomenon. The results show that the effect of PWHT can be successfully inferred by both longitudinal and shear wave methods, but the former is found to be more sensitive to stress variation. Furthermore, the distribution of subsurface residual stresses is found to be more distinguishable when the LCR method is employed.