高温合金IN718上气膜冷却孔电火花加工试验

针对高温合金IN718上ø0.5mm气膜冷却孔的加工,采用煤油中旋转电极内冲液电火花成型加工方法,利用正交试验设计方法对试验进行设计分析,分析峰值电流、脉宽、占空比和冲液压强4个因素对材料去除率和电极相对损耗的影响,基于正交试验结果建立综合评分公式,选择最优加工参数.研究结果表明,峰值电流对材料去除率的影响最明显, 其次为冲液压强和占空比,脉宽对材料去除率的影响很小;峰值电流对电极相对损耗的影响最明显,其次为冲液压强,占空比和脉宽对电极相对损耗的影响很小;最优的加工参数峰值电流为8A、脉宽为130μs、占空比为0.35、冲液压强为5MPa,对该参数进行加工试验研究,与分析结果一致. 

Experiment on electric discharge machining of cooling holes in superalloy IN718

Processing methods of electrical discharge machining (EDM) using inner jet liquid rotating electrodes under the kerosene liquid about ø0.5mm small holes on superalloy IN718 was proposed. The effects of process parameters of EDM, such as peak current, pulse on time, duty cycle and hydraulic pressure, on the material removal rate and the electrode relative-wear were studied using orthogonal design. Comprehensive formula about the material removal rate and the electrode relative-wear based on orthogonal experiment was established to choose the best processing parameters. The analysis of the results shows that the influence of peak current on the material removal is most obvious followed by the hydraulic pressure and duty cycle. The influence of pulse on time on the material removal rate is not significant; the influence of peak current on the electrode relative-wear is most obvious, followed by the hydraulic pressure. The influences of the pulse on time and the duty cycle on the electrode relative-wear are not significant; the optimization parameter group is the peak current 8A, pulse on time 130μs, duty cycle 0.35, and hydraulic pressure 5MPa. This is the optimum parameter group obtained by experimental study.