TA15钛合金真空自耗电弧熔炼过程中的富钛偏析研究

Research on Rich-titanium Segregation in TA15 Titanium Alloy during Vacuum Arc Remelting Process

通过超声波探测、显微组织观察、能谱分析及显微硬度测试等一系列表征方法,分析了实际工业生产中TA15钛合金棒材出现的富钛偏析问题。结果显示,富钛偏析区域经抛光腐蚀后呈亮白色,为α单相组织,合金元素较少,硬度低于基体。结合熔炼工艺过程分析发现,由于一次锭起弧熔炼阶段电流较小,熔炼温度较低,部分中间合金提前熔化,少量海绵钛颗粒未熔化就掉入熔池,产生富钛偏析。并且由于二次熔炼时富钛偏析处于炉内焊接部位,重熔并不能将其完全消除。通过减少或取消铸锭炉内焊接,以及对需要焊接的半成品铸锭底部进行车削处理,能够减少钛合金中的富钛偏析。

In this paper,the industry problem of rich-titanium segregation was represented by ultrasonic detection,microstructure observation,energy spectrum analysis and vickers-hardness test.The results show that rich-titanium region has the characteristics of gloss white after polishing etch,αphase,lack of alloy element and lower of hardness compared with the base.Furthermore,combined with the analysis of the smelting process,it is found that due to the smaller current in the melting stage,so the melting temperature is low,some intermediate alloys are melted in advance,and a small amount of titanium sponge particles are melted and fell into the molten pool,resulting in titanium- rich segregation.Moreover,this segregation region,becoming also a welded part ingot in the chamber,cannot be completely eliminated from follow-up remelting process.Rich-titanium segregation in titanium alloy can be reduced by reducing or eliminating welding in the ingot furnace and by turning off the bottom of the semi-finished ingot.