大厚板内部焊接残余应力分布实验研究

Measurement of internal welding residual stress distributions in a thick welded plate

本文采用两次切割轮廓法测试55 mm厚对接焊接接头的内部纵向和横向残余应力分布,分析大厚度板单V坡口多道焊接接头的内部应力特征。测试结果表明:轮廓法测试的内部应力结果和热弹塑性有限元数值计算结果符合较好;焊缝及其邻近区域的纵向应力为拉伸应力,峰值拉伸纵向应力出现在焊缝中心距上表面约10 mm深度;接头上半部分拉伸纵向应力幅值大于300 MPa,高拉伸应力分布宽度小于焊缝宽度;接头下半部分(特别是焊缝根部附近)大于200 MPa的拉伸纵向应力分布宽度远大于焊缝宽度;焊缝中心位置横向残余应力从上表面到下表面呈现拉应力-压应力-拉应力的分布趋势,距下表面0~5 mm区域为高横向拉伸应力区(大于300 MPa),且横向拉伸应力峰值出现在下表面附近。

The internal welding residual stress distributions in a butt-welded joint with a thickness of 55 mm were measured with the two-cut contour method,and the internal stress distribution characteristics in the multi-pass welding joint with a single V-type groove were analyzed.Results show that measured internal re?sidual stress distribution by contour method agrees well with those obtained by the thermal-elastic-plastic fi?nite element method;the longitudinal stress within the weld region is tensile stress and the peak value ap?pears at the weld centerline with a 10 mm distance below the top surface;the magnitude of longitudinal stress in the upper part of the weld region is larger than 300 MPa,while the stress distribution width of stress over 300 MPa is smaller than the weld width;the distribution width of the longitudinal stress over 200 MPa within the lower part of the weld is much smaller than the weld width,especially at the location of weld root.The measured transverse stress at the weld centerline exhibits a trend of tensile stress-compressive stress-tensile stress from the top surface to bottom surface,the transverse stress within the region of 0-5 mm distance from the bottom surface is large tensile stress(over 300 MPa),and the peak tensile transverse stress appears in the region near the bottom surface.