基于Fluent的涂层刀具切削热传导研究

Investigation on Heat Conduction with Coated Tools Based on Fluent

切削过程中,第二变形区刀具前刀面和切屑底部摩擦产生的热量通过刀—屑接触面流入到刀具体中,进而引起刀具温度的升高,过高的刀具温度会降低刀具强度,缩短刀具寿命。本文基于Fluent固体能量方程构建刀—屑接触面传热有限元模型,探讨涂层刀具在切削H13淬硬模具钢时涂层材料、涂层厚度和刀—屑实际接触面积对刀—屑接触面传热的影响规律。研究结果表明:在相同的刀—屑接触面温度和相同的涂层厚度条件下,Al2O3涂层对切削热传导的阻碍作用最为明显;涂层越厚,则刀—屑接触面处温差越大,较厚的刀具涂层能够有效降低刀具体内温度;刀—屑的不完全接触对刀—屑接触面处的热传导影响较大,随着刀—屑实际接触面积的减少,刀—屑接触面处的温差逐渐增加,减小刀—屑实际接触面积有利于降低刀具体内温度。

The friction heat generated in the tool-chip interface at the secondary deformation zone flows into the cutting tool and then induces the temperature rising of cutting tool. High temperature of cutting tool can reduce the tool strength and then shorten the tool life. The FE model of heat conduction in the tool-chip interface is built based on the solid energy equation of Fluent. The influences of coating materials,coating thickness and actual contact area on the heat conduction in the tool-chip interface are investigated. The research result shows that Al2 O3 coating material can provide the best thermal resistance in the tool-chip interface under the same initial temperature and the same coating thickness. With the increasing of coating thickness,the temperature drop is increasing. Thicker cutting tool coating can effectively reduce the temperature of cutting tool. The actual contact area at the tool-chip interface has the significant effect on the heat conduction in the toolchip interface. The temperature difference is increasing with the decreasing of tool-chip actual contact area. It can be deduced that the lower thermal conductivity,the thicker coating thickness and the smaller actual contact area can provide the better thermal resistance through the cutting heat flowing into cutting tool,the smaller actual contact area can decrease the temperature of cutting tool.