Abstract

This paper presents the welding residual stress distribution in thick specimens after postweld treatments (postweld heat treatment—PWHT, and ultrasonic impact treatment—UIT). Three specimens with a thickness of 40 mm were multipass butt-welded by the gas metal arc welding (GMAW). The surface stresses were evaluated by the hole-drilling (HD) and the x-ray diffraction (XRD) methods, while the internal stresses were determined by the contour method (CM). It is found that UIT has a local effect on the welding residual stress. It can convert the tensile welding stresses into compressive stresses and introduce about a 3-6 mm compressive stress layer at the treated surface with little effect on the stresses outside the treated region and the stress distribution in the interior weld zone. Additionally, UIT shows the same effect on the surface longitudinal and transverse stresses, which results in a similar distribution and magnitude of compressive longitudinal and transverse stresses on the treated regions. PWHT has a global stress release of the welding residual stress, resulting in almost uniform stress distribution in the specimen with the range from − 200 to 100 MPa. PWHT also causes the release of the compressive transverse stress in the interior.

中文翻译：

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焊后热处理和超声冲击处理后厚壁试样焊接应力分布的实验研究

摘要

本文介绍了焊后处理（焊后热处理-PWHT和超声冲击处理-UIT）后厚样品中的焊接残余应力分布。通过气体保护金属电弧焊（GMAW）对三个厚度为40 mm的试样进行多道对接焊接。表面应力通过钻孔（HD）和X射线衍射（XRD）方法进行评估，而内部应力通过轮廓方法（CM）确定。发现UIT对焊接残余应力有局部影响。它可以将拉伸焊接应力转换为压缩应力，并在处理过的表面引入约3-6 mm的压缩应力层，而对处理过的区域外部的应力和内部焊接区域的应力分布影响很小。另外，UIT对表面的纵向和横向应力显示出相同的效果，这导致在处理区域上的纵向和横向压缩应力分布和大小相似。PWHT会释放焊接残余应力的整体应力，从而使试样中的应力分布几乎均匀，范围为-200到100 MPa。PWHT还导致内部的横向压缩应力释放。