纯铁车削刀具磨损对表面完整性的影响

Effects of Tool Wear on Surface Integrity of Pure Iron Material Under Finish Turning

在微量润滑方式下采用非涂层刀具进行纯铁材料车削刀具磨损试验,并分别采用新刀具、后刀面平均磨损量为0.12和0.21 mm的已磨损刀具切削纯铁材料,研究刀具磨损对纯铁零件表面完整性的影响规律.结果表明:切削速度对纯铁精加工刀具寿命影响较大,其磨损形式以刀具后刀面刀尖磨损和沟槽磨损为主;高速时表面粗糙度随刀具磨损而快速增加,低速时则先增加后趋于平稳;切削速度为100、300 m/min时,工件表面切向和轴向残余应力随刀具磨损呈先减小后增大的变化趋势,显微硬度则呈先增大后减小的趋势;工件表层晶粒扭曲、拉伸状塑性变形程度增加,表面呈现严重的撕裂和塑性流动等缺陷.

The finish turning of pure iron material with uncoated carbide tools under minimal-quantity lubrication was performed to investigate the tool wear and its effects on the surface integrity of pure iron material turned respectively by the tool with an average flank wear of 0.12 and 0.21 mm.The results show that( 1) the life of the tool used in the finish turning of pure iron material is greatly influenced by the turning speed;( 2) the nose wear and the notch wear on the flank surface are two main wear modes of the tool;( 3) the surface roughness rapidly increases with the tool wear at a high turning speed but first increases and then changes a little with the tool wear at a low turning speed;( 4) both the tangential and the axial residual stresses on the tool surface first decrease and then increase with the increase in the tool wear at the turning speeds of 100 and 300 m / min,while the surface microhardness first increases and then decreases;and( 5) with the increase in tool wear,both the distortion and the tensile plastic deformation of grains in the surface layer increase,and serious tearing and plastic flow defects appear on the workpiece surface.