Research On The Preparing Process And Refining Effect Of Al-Ti-B Refiner Adopting Titanium Chips

Titanium and its alloys are widely used in aerospace,shipbuilding,chemical industry,medical treatment,sports goods and household goods and other fields.As it belongs to the material that is difficult to be machined,the rate of utilization in the process of production and processing is low,and it is easy to produce a large number of chips.How to reuse these chips is of vital importance to its sustainable development.The traditional titanium alloy chips recovery method is remelting method.The energy consumption is high in the remelting process,the equipment cost is expensive,the recovery process is complex,the product composition is not uniform,the recovery rate of titanium alloy chips is low,and the whole remelting process must be carried out in vacuum.In this study,Al-5Ti-1B grain refiner was prepared adopting titanium chips.In the process of titanium chips recovery,the energy consumption was low,the operation was simple,and the refiner prepared had a good refining effect.The influences of additive sequence,reaction time,reaction temperature and additive way on the microstructure of Al-5Ti-1B refiner prepared adopting titanium chip were studied.The results showed that the additive sequence mainly affected the phase composition of the microstructure of the refiner.When KBF₄ was added first and titanium chips were added later,the microstructure of the refiner was mainly composed of TiAl₃ phase and TiB₂ phase,and AlB₂ phase also existed.The reaction time mainly determines whether the titanium chip can react completely.When the reaction time is 90min,the titanium chips are completely dissolved.When the reaction time was less than 90min,there were residual undissolved titanium chips in the microstructure of the refiner.Reaction temperature mainly affects TiAl₃ phase morphology,reaction temperature higher than 900?,there are long strip TiAl3 phase in the microstructure of the refiner.The process parameters were analyzed and the dissolution model of titanium chips in the mixed additive method was proposed.The microstructure of TiAl₃ phase was fine and TiB₂ phase is uniformly distributed prepared by adding titanium chips and KBF₄ mixture before adding titanium chips.The optimal preparation process of the refiner was as follows:adding titanium chips and KBF₄ mixture before adding residual titanium chips;reaction temperature is 850-900?,reaction time was 90 min.The influences of refining temperature,refining time and addition amount of self-made Al-5Ti-1B refiner on the refining effect of industrial pure aluminum were studied.The grain size of macrostructure of refined commercial pure aluminum was compared.When refining temperature was 740?,refining time was 5 min,addition of refiner was 0.3 wt.%,self-made Al-5Ti-1B refiner showed the best refining effect.The grain size of refined pure aluminum was 400?m.By comparing self-made and commercial Al-5Ti-1B refiner products,the refiner's refining effect was evaluated with commercial pure aluminum and A356 alloy as refining objects.The results showed that the self-made refiner's refining effect was better than that of commercial bulk refiner,and the grain size of pure Al was refined was about half of that of commercial bulk refiner.However,there is still a certain gap between self-made refiner and commercial rod refiner.After refinement,the grain size of pure Al was refined was about 1.2 times of commercial rod-refiner,and the fading effect occurred when the refining time is more than 90min.