Study On Technology Of The EMC, Purification And Micro-alloying For 5356-Al Alloy

5356 aluminum alloy as a universal welding material is widely used in welding of the Al-Mg, Al-Mg-Si and Al-Zn-Mg series aluminum alloy structural materials. As the industry developing, the preparation of high-quality aluminum alloy welding wire is particularly critical because of the increasing requirements of the quality and performance of aluminum alloy wire.Adopt soft-contact electromagnetic continuous casting method and ingot casting method to produce 5356-Al alloy, the effects of the different power, casting rate, quantity of cooling water and trace amount of Sc to 5356-Al alloy are investigated. At the same time, the function of elements and the effects of C2Cl6 and C2Cl6-TiO2 melt compound purification technology on the hydrogen content of 5356-Al alloy were also analyzed by the experiments.The experiment shows 5356-Al alloy has the optimal surface and internal quality and tensile properties with the process parameters which the power is 10kw, the casting speed is 8cm/min, the quantity of cooling water is 1.7m3/h. The tensile strength and elongation of 5356-Al alloy can be up to 310.0MPa and 16.3%, and the surface has no obvious casting defects. At the same time, the microstructure of the edge is equiaxed crystals basically, while the center is broken dendrite crystals with an uniform distribution of the second phases. And, under the homogenization heat-treatment of 5356-Al alloy,440℃×30h with the air cooling, the micro-segregation of Mg has been eliminated basically and the phase Al8Mg5 which is distributing along the grain boundaries continuously dissolves significantly. Besides, trace amount of Sc can significantly improve the strength and plasticity of 5356-Al alloy. While the amount of Sc is up to 0.4wt.%, it would refine the grain size and reduce the number of the second phase, the tensile strength and elongation can be up to 330.0MPa and 29.0%, which increased by 6.5% and 77.9% respectively. In addition, there are two different kinds of refining agents:1.00wt.%C2Cl6 and 0.85wt.%C2Cl6-0.55wt.% TiO2 (accounting for burden), can both keep the hydrogen content of 5356-Al EMC billets 0.15μg/g with a high melt purified level, and no coarse impurity, obvious pore and other oxide inclusion are found in the microstructure.