钛合金叶片线切割腔道后酸洗去除重熔层研究

Research on Removal of Re-melting Layer Pickling after Wire Cutting Passage of Titanium Alloy Blade

航空发动机钛合金叶片进行电火花线切割加工腔道时,腔道内表面会产生重熔层。氢氟酸(HF)的强腐蚀性和硝酸(HNO 3)能减少钛合金吸氢,因此,为了去除钛合金叶片腔道内表面产生的重熔层,采用不同浓度比的HF和HNO 3配方进行化学酸洗去除研究。在钛合金叶片进行酸洗前,通过工艺试验确定化学酸洗溶液配方,通过超声波清洗去除油污。在酸洗过程中,通过搅拌酸洗液和上下振动钛合金叶片而增加腔道中酸洗液流动,使腔道内表面重熔层能够均匀去除。结果显示,钛合金叶片化学酸洗后基体氢增量满足标准要求,金相显微图显示重熔层被去除,且酸洗后钛合金基体无过腐蚀和裂纹。形成了一种适用于钛合金叶片在电火花线切割油道/气道后内表面产生的重熔层的去除方法。

When the aero-engine titanium alloy blade passage was machined by wire cut electric discharge machining(WEDM),the passage surface re-melting layer would occurred.The strong corrosivity of hydrofluoric acid(HF)and nitric acid(HNO 3)could reduce the absorption of hydrogen in titanium alloy,and in order to remove the re-melting layer on the inner surface of the titanium alloy blade passage,the HF and HNO 3 formulations with different concentration ratios were used to research chemical pickling removal.Before acid pickling of titanium alloys blade,through the process experiment,it was determined that the formula of chemical pickling solution,ultrasonic cleaning was used to remove machine oils.During the pickling process,the flow of pickling solution was increased by stirring the pickling solution and vibrating the titanium alloy blade up and down,so that the re-melting layer on the inner surface of the channel could be uniformly removed.The results showed that the hydrogen increment of titanium alloy blade matrix met standard requirements after chemical pickling,metallographic micrograph showed that the re-melting layer were removed,and there were excessive corrosion and crack of the titanium alloy substrate without after pickling.A method for removing re-melting layer on the inner surface of titanium alloy blades after machined oil channel/air passage by WEDM was developed.