Grooving on the tube hole will enhance the joint strength significantly, which is owing to the serious scratch between the tube and the brink of the groove.

• 管孔开槽可以明显的提高胀接接头的强度，开一个槽比不开槽的胀接接头拉脱力明显增加许多，这是由于管子和槽边缘之间的严重的“刮蹭”。