榫槽结构浸没式管电极内喷液电解切割加工

Inner-jet electrochemical cutting of mortise structure by tube electrode immersed in electrolyte

在航空发动机中,用于连接涡轮盘和叶片的榫槽/榫头结构加工精度、表面质量要求极高,现有加工技术还不能实现涡轮盘榫槽结构的低成本、高效、高质量加工。电解线切割具有加工精度高、加工表面质量好、加工灵活性强等特点,对涡轮盘榫槽结构的低成本加工具有原理性优势。针对管电极内喷液电解切割时,切缝侧壁表面粗糙度不均匀问题,提出了浸没式管电极内喷液电解切割加工方法。在较为稳定、均匀的外部流场和快速流动的加工间隙内部流场共同作用下,实现了大厚度难加工材料的高效高质量加工。结果表明,相比于管电极内喷液电解切割,浸没式管电极内喷液电解切割加工出的切缝侧壁表面粗糙度比较均匀,整体加工质量较好。优选出内喷液压力,以4.5μm/s的进给速度在20mm厚的高温合金GH4169工件上加工出表面粗糙度为Ra1.247μm的涡轮盘榫槽结构。

In the aero-engine,the machining accuracy and surface quality of the mortise/tenon structure used to connect the turbine disc and blade are extremely high.However,the existing machining technology cannot realize the low cost,high efficiency,and high quality machining of the turbine disc mortise.Electrochemical cutting has the characteristics of high machining accuracy,good surface quality and high machining flexibility,and the advantages of principle for low-cost machining of turbine disc mortise.To solve the problem of the uneven surface roughness of the sidewall cut by inner-jet electrochemical cutting using tube electrode,a method of inner-jet electrochemical cutting using tube electrode immersed in electrolyte was proposed.Under the combined action of a flow field that is relatively stable in the entire machining area and a flow field that flows rapidly in the machining gap,high efficiency and high quality machining of large thickness and difficult to machine materials is realized.The experimental results verified that the surface roughness of slit sidewall cut by inner-jet electrochemical cutting using tube electrode immersed in electrolyte is more uniform,and the overall machining quality is better compared with that of the inner-jet electrochemical cutting using tube electrode.The pressure of inner-jet electrolyte was optimized,and mortise structure of aero-engine turbine disc with surface roughness 1.247μm was successfully fabricated on a 20 mm thick superalloy GH4169 at a feed rate of 4.5μm/s and inner-jet electrolyte pressure of 2.0 MPa.