Effect of process parameters of continuous casting on microstructure and mechanical properties of pure aluminum tube

The pure aluminum tubes of d 70 mm×5mm were fabricated by heating-cooling combined mold (HCCM) continuous casting technology. The effect of process parameters on the surface quality, microstructure and mechanical properties of tubes were analyzed. The results show that pure aluminum tubes can be continuously and stably fabricated without defects on the internal and external surfaces, when casting temperature is 750℃, mold heating temperature is 700-720℃ and cooling water flow rate is 1000 L/h. The microstructure of tubes have strong axial orientation columnar-grains on external surface when the continuous casting speed is 20-60 mm/min, and the grain size gradually decreases with the increasing of casting speed. When the continuous casting speed is 80-100 mm/min, the surface microstructure of tubes gradually transforms to equiaxed grains. When the heating-mold temperature and the casting speed are 720℃ and 60 mm/min, the surface roughness value of pure aluminum tubes fabricated is less than 1.6 μm, the tensile strength is 58.4 MPa, the yield strength is 20.6 MPa, and the elongation is 28.9%. This shows that tubes can be directly cold machining without milling surface, which can significantly shorten the production process. © 2021, China Science Publishing & Media Ltd. All right reserved.