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对位于应力集中区并且可能受到焊接角变形引起的附加弯矩作用的有限长度的焊趾裂纹来说,裂纹部分前沿总处于高应力区,其最大应力强度因子不在裂纹底部而在裂纹表面附近。裂纹底部处于平面应变状态而裂纹的表面前沿处于平面应力状态。焊趾裂纹对超高强度钢的静载强度的影响是否大于相同尺寸的平板表面裂纹是一个问题。本文对37SiMnCrMoV超高强度钢进行了宽板拉伸试验。试件上加焊各种不同刚度的附件,并在附件角焊缝趾部开人工裂纹,裂纹的深度有0.2板厚和0.4板厚两种,裂纹深长度比(a/(2c))分别为0.05和0.1。同时进行带同样尺寸裂纹的平板试验作对比。试验结果表明:对干37SiMnCr MoV钢而言附件焊趾裂纹对静载强度的影响大于平板上的表面裂纹。这种影响随着附件刚度增加而加剧。
For a finite length weld toe crack located in a stress concentration zone and likely to be subjected to additional bending moments caused by deformation of the weld, the front of the crack is always in the high stress zone and its maximum stress intensity factor is not near the crack surface but near the crack surface. The bottom of the crack is in the plane strain state and the front edge of the crack is in the plane stress state. Whether the weld toe crack has an effect on the static load strength of the ultra-high strength steel is greater than the surface crack of the same size plate is a problem. In this paper, 37SiMnCrMoV ultrahigh strength steel was subjected to a wide plate tensile test. The test pieces were welded with various attachments of different rigidities, and artificial cracks were formed in the fillet weld toe of the attachment. The depth of the crack was 0.2 and 0.4 thick, respectively, and the ratio of crack depth to length (a / (2c)) 0.05 and 0.1. At the same time with the same size crack plate test for comparison. The experimental results show that the influence of weld toe crack on the dry load strength of dry 37SiMnCr MoV steel is larger than the surface crack on the flat plate. This effect is exacerbated by the increased rigidity of the attachment.