四、拉刀的热处理缺陷 拉刀热处理中最主要的缺陷有裂纹、荼状断口、硬度不足、校直压断等。以下作粗浅探讨。 1.裂纹 裂纹是拉刀热处理过程中最严重的一种缺陷,是无法挽救的,除报废外别无他法,经济损失很大。原因常有以下几方面: (1) 淬火过热 当淬火温度高至引起碳化物沿 Fourth, the broach heat treatment defects Broaching heat treatment in the most important defects are cracks, tea fracture, lack of hardness, straightening and so on. The following for a superficial discussion. Crack cracks are the most serious flaw in the broaching heat treatment process is irreparable, in addition to scrap no alternative, a great economic loss. Reasons often have the following aspects: (1) quenching overheating When the quenching temperature is high to cause carbide along