结构钢件焊接时,在焊接规范、焊条和母材相同的条件下,常常发现甲焊工焊的焊缝在中心处有裂纹,而乙焊工焊的却没有。从这两名焊工所焊的工件上切取焊缝横断面试样。分析结果表明,甲焊工焊的每道焊缝的特点是窄而深,而乙焊工焊的每道焊缝的特点是宽而浅。焊缝的形状系数是指焊缝的宽度与深度之比。窄而深的焊道,形状系数是小的;宽而浅的焊道,形状系数是大的。为什么在窄而深的焊缝中心线上容易形成裂纹呢? Structural steel welding, welding specifications, welding rod and base metal under the same conditions, often found in a welder seam welding cracks in the center, and B welder did not. Sections of the weld cross-section were cut from the workpieces to be welded by the two welders. The results of the analysis show that the characteristics of each weld in a welder are narrow and deep, whereas the characteristics of each welder in a welder are wide and shallow. The shape factor of the weld is the ratio of the width to the depth of the weld. Narrow and deep bead, the shape factor is small; wide and shallow bead, the shape factor is large. Why is it easy to form a crack on the narrow and deep weld centerline?