对流换热对TC4合金切屑断裂的影响机制研究

Research on the Influence Mechanism of Convective Heat Transfer on Chip Fracture of TC4 Alloy

研究钛合金的切屑断裂机制有利于实现合理断屑,进而改善加工效率和加工质量。基于高速正交铣削试验,在不同切削速度和冷却条件下对TC4合金进行了高速加工,并通过显微镜对切屑锯齿化程度进行了分析,进一步结合二维切削仿真,探究了对流换热条件对切削变形区温度和应变率的影响规律,以揭示钛合金切屑的断裂机制。研究结果表明,高切削速度和合理的冷却可以促进切屑的形态转变,提高材料去除效率;冷却液的对流换热能力越强,切削区域温度越低,切屑的锯齿化程度越明显。在高速加工过程中,采用强对流换热冷却液可以改善材料断屑。

The investigation of chip fracture mechanisms in titanium alloys is beneficial for achieving rational chip fracture and thus improving machining efficiency and machining quality.In this paper,based on orthogonal milling experiments,high-speed machining of TC4 alloy was carried out at different cutting speeds and cooling conditions,and the degree of chip serration was analysed by microscopy.Further,the effect of convective heat transfer conditions on the temperature and strain rate of the cutting deformation zone was investigated in conjunction with two-dimensional cutting simulations to reveal the fracture mechanism of titanium alloy chips.The results of the study show that high cutting speeds and a reasonable cooling effect can promote chip morphological transformation and improve material removal efficiency.The stronger the convective heat transfer capability,the lower the temperature of the cutting area and the more pronounced the degree of chip serration.During high-speed machining,the use of strong convection heat transfer coolant can improve chip serration and chip breakage.