探索闭式热模锻成形时材料的流动规律是控制充填不满等成形缺陷、获得高精度模锻件的理论基础。针对深轮辐齿坯件热模锻成形时易出现填充不满的问题，以某SCr420H深轮辐齿坯为研究对象，基于齿坯件结构分析，设计了“下料—加热—镦粗—预锻Ⅰ—预锻Ⅱ—终锻”的多工位闭式热模锻工艺方案；基于Deform软件，构建了深轮辐齿坯件多工位闭式热模锻全流程有限元模拟模型；采用试验验证了有限元模型的可靠性，并对多工位闭式热模锻成形过程中材料的流动规律进行了研究。结果表明：镦粗比为3.7时，可获得外形良好的圆饼形预制坯，镦粗时受上下表面摩擦效应的影响，材料径向流动不均匀，在坯件腰部出现鼓形；预锻Ⅰ工位成形出用于定位的底面内凹结构，同时减小了后续工位材料填充难度；预锻Ⅱ和终锻成形时的材料流动规律相似，成形前期材料集中流向轮缘部分、成形中期主要流向轮毂部分、末期流向圆角处；终锻成形时未出现材料填充不满的缺陷，在成形后期，少量金属材料从终锻上下模的导向间隙中流出，形成纵向飞边。通过生产试验，成形出填充良好的深轮辐齿坯件，模拟数值获得温度与实际生产数值最大误差不超过3.15%，纵向飞边高度小于0.5 mm，零件各尺寸偏差均小于0.2 mm，验证了所设计多工位闭式模锻工艺的合理性。

Exploring the material flow behavior during the closed die forging is the theoretical basis for controlling forming defects such as insufficient filling and obtaining high-precision die forgings. In response to the problem of insufficient filling during hot die forging of gear blanks with deep spoke, this study selected the SCr420H gear blank with deep spoke as the research object and designed a multi-station closed hot die forging process of “cutting—heating—upsetting—preforging Ⅰ—preforging Ⅱ—final forging” based on structure analysis of the gear blank. Based on Deform, it established a finite element simulation model for the entire process of multi-station closed hot die forging. The reliability of the finite element model was verified by the experimental results, and the material flow law during the multi-station closed hot die forging process was studied. The results show that a circular cake shaped blank can be obtained when the upsetting ratio is 3.7. The material flow along radial direction is uneven due to the friction effect between the upper and lower surfaces, resulting in a bulge shape at the waist of the billet during upsetting. A concave structure was formed on the bottom surface for positioning during pre-forging station Ⅰ, and it reduced the difficulty of material filling in subsequent stations. The material flow law during pre-forging Ⅱ and final forging are similar. The material mainly flows to the wheel flange part in the early stage of forming. It mainly flows to the wheel hub part in the middle stage, and flows to the rounded corner in the late stage. There is no defect of insufficient material filling during final forging. In the late forming stage, a small amount of metal material flows out of the guide gap of the upper and lower die of the final forging, forming a longitudinal flying edge. Through the production test, the well-filled gear blank with deep spoke was formed. The maximum error between the simulated value and the actual production value is not more than 3.15%, the longitudinal flying edge height is less than 0.5 mm, and the size deviation of each part is less than 0.2 mm, which verifies the rationality of the designed multi-stage closed die forging process.