9AT 汽车变速器离壳体油路管道、加强筋等复杂结构集中于右侧，对称性差，气密性要求高，导致成型难度大，生产合格率较低。 压射速度是影响产品合格率的关键因素，本文通过计算确定了工艺参数并模拟了 3 组不同流速对金属液流动和缺陷率的影响。结果表明，当浇注温度为 680 ℃ 、压射速度为 3.5 m/s 、模具温度为 200 ℃ 时流速最为平缓，产生的缩松缩孔体积最小。 用该组工艺参数进行压铸实验，并对铸件进行组织形貌观察和性能测试，其抗拉强度和伸长率分别为 257.3 MPa 、 4% 。 变速器离壳体产品性能和质量满足使用要求，产品合格率由原来的 65.3% 提高到 77.5% 。

Complex structures such as the oil pipeline and reinforcing ribs from the case of 9AT automobile transmission are concentrated on the right side, resulting in poor symmetry and high requirements for airtightness, which lead to great molding difficulties and low production qualification rates. The injection velocity is a key factor affecting the product qualification rate. In this paper, the process parameters were determined through calculation, and the effects of three different flow rates on the metal liquid flow and defect rate were simulated. The results show that when the pouring temperature is 680 ℃, the injection speed is 3.5 m/s, and the mold temperature is 200 ℃, the flow rate is the gentlest, creating the smallest volume of shrinkage porosity and shrinkage cavity. Die casting experiments were carried out with this set of parameters, the microstructure and morphology of the castings were observed, and performance tests were conducted. The tensile strength and elongation are 257.3 MPa and 4%,respectively. The performance and quality of the transmission case product meet the use requirements, and the qualified rate of the products increases from 65.3% to 77.5%.