利用自行设计的连续半固态扩展挤压成形装置制备6201铝合金管材,并采用数值模拟研究此过程的温度场和流场分布规律.结果表明:辊-靴型腔内合金的温度从入口到出口处逐渐降低,等温线向轧辊侧偏移,金属流动速度沿工作辊表面向辊靴表面依次递减.在扩展挤压模具内,合金呈放射状填充到模具中,温度由入口到出口处逐渐降低,且模具扩展腔中心的温度高于壁面的温度.分流孔中心位置和焊合部位对应的成形管材截面流线密集,此处相应的金属硬度也高,在两者之间出现8条流线的舒缓过渡带.为制备表面质量良好的6201铝合金管材,合理的浇注温度为750～780℃.
A continuous semisolid extending extrusion (CSEP) method was proposed.Temperature field and metal flow during continuous semisolid extending extrusion process of 6201 alloy tube were studied.During the process,the temperature in the roll-shoe cavity decreases gradually,and the isothermal lines of the alloy deviate from the shoe side to the work roll side in the roll-shoe gap.Metal flow velocity decreases gradually from the surface of the work roll to the surface of the shoe.In the extrusion mould,alloy temperature decreases gradually from the entrance to the exit and from the center to the sidewall of the mould.The extending cavity is radially filled with the alloy.The flow lines in the tube corresponding to the centers of the splitflow orifices and the welding gaps are dense,and the corresponding harness values are high; there are 8 transitional bands between them.In order to prepare 6201 alloy tubes with good surface quality,the pouring temperature from 750 ℃ to 780 ℃ was suggested.
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