利用空间几何关系及坐标变换原理,推导出空间焊接节点管管相贯时相贯线平面展开公式。通过该公式的计算,可以准确、方便地绘出相贯线的平面展开图形,利用图形放样或与数控机床连接,可以进行相贯口的切割。文中公式不但用于球节点多管相贯,也可用于管桁架多管相贯。 Based on the geometric relations of space and the principle of coordinate transformation, the plane expansion formula of the intersecting lines of space welded joints is deduced. Through the calculation of this formula, it is possible to draw the plane expansion pattern of the intersecting lines accurately and conveniently, and to make the cutting of the intersecting mouth by using the figure lofting or connecting with the numerical control machine tool. The formulas in this paper are not only used for the multi-tube intersection of the ball joints, but also for the multi-tube pipe trusses.