【摘要】 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。更多还原

【Abstract】 Weld toe cracks are located in the stress concentration region and are often subjected to the additional moment caused by angular welding distortion. For a toe crack of finite length, the crack front near the surface lies in a zone of higher stress than that of a surface crack of the same size on a flat plate under similar loading conditions. The material near the surface is in a plane-stress condition and that at the bottom in a plane-strain condition. The fracture toughness of the material at the crack front near the surface of the plate is higher than that at the bottom. Whether the influence of a weld toe crack on the static strength is greater than lhat of a surface crack on flat plate remains a question. In this paper, Wide plate tensile test were performed. Attachments with different stiffness were welded on to 37SiMnCrbioV high strength steel specimens. The cracks(a/2c=0.05, 0.1; a/t=0.2, 0.4)were cut by electric spark method at the toe of fillet weld. Experiments were also made on wide plate specimens without welded-on attachments for comparison. It is shown that the influence of the weld foe crack on the static strength(pop-in)of 37SiMnCrMoV steel plate with welded-on attachments is greater than that of a surface crack of the samesize on a flat plate, if the crack size is so large that the fracture stress is below yelding point. The higher the stiffness of the attachment, the greater the influencewill be,更多还原