A型排气歧管的结构复杂,高度落差较大,管壁薄,技术要求严格,生产工艺难度较大。初始工艺设计为顶注封闭式浇注系统,横浇道贯穿两个热侧冒口进流,采用过滤网。主要问题是浇注过程中进渣,形成渣 A-type exhaust manifold complex structure, a larger height drop, thin wall, strict technical requirements, the production process is more difficult. The initial process design for the top-note closed pouring system, runner run through the two hot-side riser flow, the use of filters. The main problem is the slag into the process of casting, forming slag