| To promote the application of semi-solid forming to industry, the numerical simulation technology has been applied to the analysis of the process of AlSi9Mg alloy semi-solid billet production by pouring near liquids. The effect of pouring temperature, pouring height, pouring velocity and cooling condition on the velocity field and temperature gradient has been investigated, and the effect on microstructure of the semi-solid billet has also been researched. The results of numerical simulation and experiment shows that: the liquid metal flows mainly along axis, only a little metal along radius, but more and more metal will flow along radius. As a result, the shearing strength of the liquid metal is very large, which have a significant influence on the forming of non-dendrite grains. A lower pouring temperature, a lower cooling intensity, a higher pouring height and a higher pouring velocity are prone to forming spherical or nodular grains.Then based on the results of the numerical simulation and the principle of the orthogonal experimentation, select appropriate technical parameters, and research the relation of the technical parameters. The result shows that as far as the temperature, the effect of cooling intensity is the biggest, following with pouring temperature, pouring velocity, pouring height. Compared with the effect of the cooling intensity, the others can be ignored. As far as the flow field, the effect of pouring velocity is the biggest, following with pouring height, pouring temperature, cooling intensity. Compared with the effect of the pouring velocity, the others can be ignored. The best technical parameter array is the one of pouring temperature is 610℃, pouring velocity is 1.2kg/s, pouring height is 20mm, and the die heat up to 200℃.The experiment result of the true process shows that the result of the numerical simulation is correct, and this technology can obtain the wonderful AlSi9Mg alloy semi-solid billet with spherical or nodular grains.
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