真空自耗重熔是镍基变形高温合金冶炼的终端工序，其熔池特征直接决定铸锭的洁净度和冶金质量。本工作基于直径690 mm的GH4738合金大型铸锭的真空自耗重熔工艺特性，建立了电磁-流动-传热及夹杂物运动的多场耦合模型，分析了重熔过程中的熔池特征以及夹杂物的运动轨迹与分布规律，探究了熔炼电流强度、氦气冷却压力和电弧形态变化对真空自耗重熔过程中熔池流动和夹杂物运动行为的影响。结果表明，在重熔过程中，熔池主要呈现稳定的环形流场结构，夹杂物在熔池中的运动表现出明显的流动跟随性和尺寸效应。当熔炼电流强度从8 kA增加至10 kA时，电磁场强度和热输入显著增强，促使夹杂物向熔池内部迁移。氦气冷却压力提升至400 Pa有助于优化熔池形貌、抑制湍流发展，同时防止夹杂物卷入。电弧形态由扩散弧转变为收缩弧则重构了电磁场分布，诱发双环流结构，导致夹杂物向铸锭中心聚集。通过合理调控熔炼电流强度和氦气压力，维持浅平熔池形貌并稳定电弧扩散模式，是实现夹杂物高效去除的关键路径。

As the final step in the production of nickel-based wrought superalloys, the characteristics of the molten pool in vacuum arc remelting (VAR) have a decisive impact on the cleanliness and metallurgical quality of the ingot. In this study, a multiphysics coupling model integrating electromagnetic effects, fluid flow, heat transfer, and inclusion motion was developed based on the process characteristics of a large-scale vacuum-arc remelted GH4738 superalloy ingot with a diameter of 690 mm. Using this model, the molten pool characteristics, along with the motion trajectories and distribution patterns of inclusions during VAR, were systematically investigated, with particular focus on evaluating the influences of arc current intensity, helium gas cooling pressure, and arc morphology evolution on molten flow and inclusion migration behavior. Results indicate that during remelting, the molten pool primarily exhibits a stable annular flow structure, with inclusion movement exhibiting distinct flow-driven behavior and pronounced size-dependent effects. As the melting current increases from 8 kA to 10 kA, the electromagnetic field strength and thermal input are enhanced, thereby promoting more active inclusion migration within the molten pool. Optimizing the helium cooling pressure to 400 Pa effectively improves molten pool morphology, suppresses turbulence development, and mitigates inclusion entrapment. The arc morphology transition from a diffuse to a constricted configuration fundamentally alters the electromagnetic field distribution, establishing dual circulatory flow patterns that drive inclusion accumulation toward the ingot's central region. Therefore, by rationally regulating the melting current and helium pressure, maintaining a shallow and flat molten pool, and stabilizing the diffuse arc mode, efficient inclusion removal can be achieved as a key processing strategy.