电弧等离子体加工中温度与热应力研究

Research on Temperature and Thermal Stress in Arc Plasma Machining

为探究电弧等离子体对熔融石英的热去除加工方法的可行性,采用有限元数值模拟分析方法建立电弧等离子体作用下熔融石英的表面温度与热应力模型,分析电弧加工参数变化对熔融石英表面温度以及热应力分布的影响。仿真分析结果表明:电弧等离子体炬产生的热量能够使得熔融石英表面温度在0.2~0.35 s内达到2100 K至2450 K之间,可保证被加工材料表面温度处于熔融区间,形成微流动填补质量缺陷。在工件表面驻留时间小于0.3 s时,可避免气化损伤,保证材料处于熔融态,产生的拉应力最大值为42.25 MPa,压应力最大值约为781.65 MPa,均小于损伤强度阈值。该方法可实现对熔融石英无热应力损伤的热去除加工。

The paper aims to explore the feasibility of the method for heat removal processing of fused quartz by arc plasma.The finite element numerical simulation analysis was used to establish the model of fused quartz surface temperature and thermal stress under the action of arc plasma,and the influence of the arc processing parameters on the surface temperature and thermal stress distribution of fused quartz was analyzed.The simulation results show that the heat generated by the arc plasma torch can raise the surface temperature of fused quartz to between 2100 K and 2450 K within 0.2~0.35 s,ensuring that the temperature of the surface material which is being processed is in the melting range,forming micro-flow to make up for quality defects.When the surface dwell time of the workpiece is less than 0.3 s,the gasification damage can be avoided,which ensures that the material is kept in the molten state.The maximum tensile stress and compressive stress are 42.25 MPa and 781.65 MPa respectively,both lower than the damage strength threshold.It is concluded that the method works effectively for the thermal removal processing of fused silica without thermal stress damage.