Study On The Key Technology Of Purification Treatment Of A New Refiner AlTiBRE Processed By In-situ Reaction

Aiming at the problems currently existing in grain refiner AlTiBRE master alloy processed by in-situ reaction, that is, congregating tendency of the refinement particles and more metallurgical defects(higher content of inclusions and hydrogen) resulting in polluting aluminum melt again, thus directly influencing the production and application, based on the previous study in this paper, high efficient purification was used to treat the refiner to develop a new AlTiBRE refiner with excellent quality by means of modern analyses and testing techniques such as OM,SEM,EDAX,XRD,etc, which was applied to the refinement of aluminum alloy. Then the effect of refinement are further discussed. The results are as follows:1. Four kinds of fluxes for removing inclusions are designed to purify the refiner, which are CJ1 flux, CJ2 flux, CJ5 flux and CJ6 flux. The experiment results show that the proportion of the ingredients of the CJ5 flux is appropriate, the rate of removing inclusion is up to 82.8%. The main reason for the better refinement of CJ5 flux is that the melting point of conventional fluxes are almost over 650℃, the CJ5 flux is only 601.0℃ which is lower than the others. Therefore the degree of superheat is higher and the viscosity is lower under the same treatment temperature. And with better fluidity and the distribution shape of refining phrase particles can be improved, thermodynamics and kinetics condition of purification have been further improved.2. The distribution of the refinement particles of the refiner can be improved through high efficient flux removing inclusions. After purifying by CJ5 flux, the distribution and morpholopy of TiAl3 refining phrase particles has been further improved. TiB2 particles in the master alloy distributed homogeneously without congregation. Combined with effective purification, the electromagnetic can further improve the distribution form of refining particles.3. A kind of filter layer process appropriate for flux for removing inclusions of master alloy refiners for the production of the new A15TilB0.5RE refiner by in-situ reaction and a key purification technology combined argon blowing with complex active flux, which can reduce the inclusions and hydrogen inside the refiner and improve homogeneity distribution of the refinement particles of the refiner. The refiner made by the purification technique (12#), the rate of removing inclusion is up to 83.6%. TiAl3 particles show little well-distributed block, the average size is 16.8μm. Comparing the A15TilB0.5RE made in lab, A15TilB and AlTiBRE on the market, the new refiner has the highest rate of removing inclusion and distributes more homogeneously, which solves the problem of transition of laboratory achievements into applications of this new refiner.4. The refining effect of A15TilB0.5RE(12#) refiner self-made under productive condition was proved to be better than that of the commercial refiner A15Ti1B and AlTiBRE, and equivalent to that of lab-made refiner AlTiBRE. The appropriate refining technique on commercial purity aluminum is that the proper Ti content is 0.1% under the temperature of 740℃. The refiner also has a significant refining effect on 1070 aluminum alloy produced directly by electrolysis aluminum liquid, which is better than the commercial refiner A15TilB. The main reason for the good refining effect of AlTiBRE refiner self-made under productive condition is the smaller particle size of TiAl3, and the uniform dispersion distribution of TiB2 and the best inner cleaning degree. Therefore when added into aluminum melt, the A15TilB0.5RE(12#) refiner will not pollute aluminum melt again, TiB2, TiAl3 and RE can also distribute rapidly and uniformly. Thus the A15TilB0.5RE(12#) refiner can quickly achieve good refinement effect and maintain long-term stable refinement effect.5. The purity of AlTiBRE refiner has a significant influence on the refinement effect of aluminum alloy. The purity of refiner is better, the distribution and morphology of refinement phase particles are closer to the ideal state, the refinement is better.