钢的切屑变形和断裂

通过光镜(LM)与扫描、透射电镜(SEM、TEM)研究碳钢在机械加工中,切屑形成过程的变形与断裂特征。单相与多相合金材料的断裂行为有所差别,单相合金仅有一个断裂部位,它位于刀尖处,已加工表面与切屑交界,切屑的形态取决于该断裂行为;多相合金有第二个断裂部位,位于刀屑底部与刀具前刀面交界处,是产生积屑瘤(BUE)的基本条件之一,并影响工件表面加工质量。

Deformation and fracture of Chip in steel

During machining of carbon steel, the characteristics of deformation and fracture in chip formation are studied by light microscope, scanning electron microscope, and trans- mission electron microscope, the fracture behaviour of homogeneous alloyed material differs from that of heterogeneous one. In the former, only one separation (fracture) point may oc- cur in the boundary between machined surface and chip at tool tip. The shape of the chip de- pends on the fracture behaviour. In the latter, an additional separation point may occur in the boundary between chip bottom and rake face. It serves as a basic condition for the forma- tion of built-up edge (BUE) and affects the surface finishing quality of the workpiece.