改善钛合金切削加工性的置氢工艺及置氢量优化

Optimization of Hydrogenation Process and Hydrogenation Concentration in Improving Titanium Alloy Machinability

为了改善钛合金的切削加工性能,提出将钛合金进行置氢处理后再进行切削加工。在650℃、750℃和800℃下对Ti-6Al-4V合金进行了置氢处理,并在干切削条件下对其开展了切削力、切削温度对比试验。结果表明:在置氢工艺相同时,随着置氢量增加,热电偶的热电势系数越来越大;主切削力在650℃置氢时相对未置氢试件仅降低2%,750℃置氢时没有降低,而800℃置氢时主切削力约下降了8%;切削温度均呈现先快速降低、经过一平缓变化段后又快速增加的变化趋势,在650℃、750℃和800℃置氢情况下,切削温度相对未置氢试件分别约降低了50℃、76℃和80℃。最终确定优选的置氢工艺为:在800℃下置氢、保温6h、随炉冷却至室温;最佳置氢量范围为0.21%～0.37%。

The titanium alloy is a kind of typical difficult--to--cut material. Before machining, the titanium alloys were processed at 650℃, 750℃ and 800℃ by thermohydrogen treatment technology respectively in order to improve the machinability. The measurement experiments about cutting force and cutting temperature were carried out in dry cutting. The results show that, when the hydrogenation process is identical, thermoelectromotive force coefficient increases with the increase of hydrogen concentration. respectively, the main When the Ti -- 6Al-- 4V cutting force falls 2;, alloy was hydrogenated at 0; and 8; respectively. 650℃,750℃ and 800℃ Moreover, the cutting temperature firstly rapidly reduces, secondly flatly changes, thirdly rapidly increses with the increase of hydrogen concentration, and the cutting temperature reduces 50℃, 76℃ and 80℃ respectively under the three hydrogenation temperature. The preferred hydrogenation process of Ti--6A1--4V is as follows,the process is concluded at 800℃ for 6 hours, then cooled in the furnace, and the optimum hydrogen concentration ranges from 0.21; to 0.37