精密硬态切削过程中已加工表面变质层生成研究

Deteriorative Layer Formation on Machined Surface in Precision Hard Cutting Process

精密硬态切削过程中刀具与工件发生剧烈的热力耦合作用,使得一定条件下已加工表面出现变质层.为揭示变质层的生成机制,研究了PCBN刀具硬态切削淬硬模具钢Cr12MoV的工艺过程.通过实验手段揭示了表面变质层生成机理,得到了不同刀具磨损情况下变质层中白层厚度的变化规律;采用MATLAB数学分析软件构建了已加工表面温度场分布曲线,预测了特定切削条件下变质层中的白层厚度.实验验证结果表明:该模型预测精度较高,可以为精密硬态切削加工过程中工件加工质量的控制提供依据.

Severe thermodynamic coupling effect occurs between tool and workpiece during precision hard cutting process, which causes deteriorative layer to appear on finished surfaces. To reveal the formation mechanism of deteriorative layer, the process of PCBN tool cutting hardened steel mould Crl2MoV was studied. The formation mechanism of deteriorative layer and the variation of white layer thickness with tool wear were revealed through experiment. Temperature field distribution on machined surface was obtained using mathematics analysis software MATLAB, based on which, the white layer thickness was predicted under specific condition. Experimental results show that the model has high prediction accuracy. It can provide basis for machining quality control in hard cutting process.