live knot,light knot,tight knot;swivel,unsound knot

The experimental method and steps of steel ball head bolt upset forming technology are introduced herein.

锅炉用钢制活节螺栓镦锻成形工艺的试验方法及试验过程,并对试验结果进行分析,证明该工艺在实际生产中的可行性,该工艺已经用于实际生产。