卡瓦类型的自由锻件最容易在内圆弧尖角处发生缺肉的毛病(见附图中A处)为避免产生这种缺陷,《锻工手册》第四分册介绍了一种弯曲成型法,其工艺过程见表1。这种方法只适用于锻造薄壁的大型卡瓦,而且弯曲工艺操作难度较大。特别是弯曲部分的展开长度很难确定,即在表1所示的第2道工序中,如果中间部分拔长不适当,就会在弯曲后形成无法挽救的的废品。 Free-forgings of slip type are the most susceptible to nicking at the sharp corners of the internal arc (see A in the figure). To avoid this, the fourth volume of the Forging Workbook describes a bending method , The process shown in Table 1. This method is only suitable for forging thin-walled large slip, and bending process operation more difficult. In particular, it is difficult to determine the unfolding length of the curved portion. In the second step shown in Table 1, if the intermediate portion is not pulled properly, an irreversible waste product is formed after bending.