Preparation And Refinement Performance Of Al-5Ti-1B Alloy Wire Produced By Electromagnetic Stirring And CASTEXP Process

Grain refinement is an effective method to improve mechanical properties of materialand Al-Ti-B master alloy wire is the most widely used grain refiner in aluminum industry.However, domestic Al-Ti-B master alloy has many problems, such as low purity, poor shapeand distribution of TiAl₃and TiB₂particles, compared with the similar foreign products. As aresult, domestic Al-Ti-B master alloy was unable to meet the requirement of production ofhigh quality aluminum plate, strip and foil. Preparation of high quality Al-Ti-B master alloyhas been required for the development of aluminum processing industry. In this paper, a kindof high quality Al-5Ti-1B master alloy was prepared by Continues Casting and Extrusion（CASTEX） forming technique. The alloy preparation and wire forming parameters werestudied and optimized.Experimental results showed that optimal fluoride salt addition amount was5%morethan normal amount. The fluoride salt addition order was adding part of K₂TiF₆first and thenadding K₂TiF₆and KBF₄uniform mixture. The optimal reaction temperature was850-880℃and the optimal reaction time was60-90min. Through electromagnetic stirring of Al-5Ti-1Bmaster alloy melt in the tundish, the accumulation and precipitation of particles wereeliminated and the melt purity of Al-5Ti-1B master alloy was improved. The viscous forcewas influenced by temperature. The distribution uniformity of particles could be improved byincreasing electromagnetic stirring temperature and time. The most suitable electromagneticstirring temperature and time were790℃and20min respetively.The Al-5Ti-1B master alloy wire prepared by CASTEX forming technique had smoothsurface and uniform microstructure. Action of shear and rub moves force made TiAl₃andTiB₂particles distribute uniformly in the master alloy wire. A casting and extrusiontemperature of790℃and a casting extrusion wheel speed of20r/min were used to prepare thehigh quality Al-Ti-B master alloy wire. The optimal refinement effect was obtained by adding0.2weight percent of refiner with angulatus block TiAl₃and evenly dispersed small TiB₂particles at700-730℃for5min. Through industrial test and comparison with home andabroad similar products, the comprehensive performance of Al-5Ti-1B master alloy wire prepared by CASTEX forming technique was excellent and could meet the requirements ofindustrial application.