气体压力对钛合金电火花诱导烧蚀加工的影响  

Influence of Gas Pressure on EDM Ablation of Titanium Alloy

作　　者：王祥志[1] 刘志东[1] 邱明波[1] 田宗军[1] 黄因慧[1] 

机构地区：[1]南京航空航天大学机电学院,江苏南京210016

出　　处：《航空学报》2014年第12期3480-3488,共9页Acta Aeronautica et Astronautica Sinica

基　　金：国家自然科学基金(51175256;51205197);江苏省自然科学基金(BK2011732)~~

摘　　要：氧气在电火花(EDM)诱导烧蚀加工过程中起到参与氧化放热、蚀除金属和冷却的作用。以气体压力为研究对象,通过理论推导,证明增加气体压力可提高气体流速、减小气体分子平均自由程、提高氧化扩散速度和气体蚀除力以及加速能量散失。通过测得不同气体压力下的击穿电压、击穿延时和工作电压,试验证实了气体压力对击穿电压和击穿延时有较大影响;通过建立EDM诱导烧蚀加工放电等效模型,表明工作电压变化是由电极和工件表面氧化引起的。研究了气体压力对EDM诱导烧蚀加工材料蚀除率(MRR)、相对电极损耗(REWR)和表面粗糙度的影响。结果表明:随着气体压力增大,材料蚀除率先增加后降低,电极相对损耗缓慢减小,表面粗糙度显著降低。In the electrical discharge machining （EDM） ablation process,the oxygen take an important role in the process of oxidation heat,metal corrosion and cooling.Investigation on the effect of gas pressure on improving the gas flow rate,decreasing the molecular mean free path of gas,improving the oxidation diffusion velocity,accelerating the energy dissipation is carried out.Breakdown voltage,the breakdown delay and working voltage under different gas pressure is tested,results show that breakdown voltage and breakdown delay characteristics is greatly influenced by gas pressure.Machining equivalent model of EDM ablation is established to prove that the change of working voltage is caused by the oxidation of the surface of electrode and workpiece.Influence of gas pressure on the material removal rate （MRR）,relative electrode wear rate （REWR） and surface roughness in the EDM ablation is studied.The results show that with the increase of gas pressure,material removal rate increases firstly and then decreases,relative electrode wear decreases slowly and the surface roughness is significantly improved.

关 键 词：电火花加工 烧蚀 钛合金 气体压力 氧扩散 

分 类 号：V216.61[航空宇航科学与技术—航空宇航推进理论与工程] TG661[金属学及工艺—金属切削加工及机床]