摘要
一般认为,当切屑弯曲应变ε达到或大于其断裂应变ε_B 时,切屑便发生断裂。但这一判据必须以切屑是属于韧性断裂为前提。针对这一问题,作者观察和研究了切屑断口的形貌,证实钢屑在切削过程中的断裂是属于韧断。从而用ε≥ε_B 作为断屑的判据。作者对其他形式的判据进行了分析,认为均不适用于钢屑的断裂。此外,本文还研究了夹杂物的存在对切屑折断的影响以及断屑时裂纹走向等问题。
By observing and analysing the shape-appearance of the broken sections of chips with the scanning electromicroscope,it is clear that the character of chip breaking is ductile fracture of coalessence of voids.Therefore,the compar son between the chip bending strain and chip broken strain can be used as the criterion for forecasting chip breaking.In addition,the influence of mingled substance in the chip on the chip breaking and the direction of crack propaga- tion in the chip have been studied.
关键词
切屑
断口
断裂
钢
broken section scanning electromicroscopc
