Electron Beam Melting Marangoni Convection for Impurity Control

The patent applies local quality by creating a specific temperature distribution pattern in the hearth. An electron beam is radiated along a line extending from the center toward the downstream side, creating a localized high-temperature region that generates Marangoni convection. This localized thermal action modifies the flow characteristics in the impurity-prone downstream region without disrupting the overall melting and pouring process, thereby preventing LDI escape while maintaining production efficiency.

The patent changes the thermal parameters of the molten metal by introducing a controlled temperature gradient through selective electron beam irradiation. By radiating the electron beam along a specific line from the center toward the downstream side, the system creates a deliberate temperature distribution that drives Marangoni convection. This parameter change (temperature gradient) fundamentally alters the flow dynamics to trap impurities in the upstream region, resolving the contradiction between efficient flow and impurity prevention.

The patent replaces the mechanical solution of using a long hearth (physical extension of the heating zone) with a fluid dynamics-based solution. By inducing Marangoni convection through controlled temperature gradients, the system achieves enhanced impurity removal through intensified mixing and circulation. This substitution allows for a shorter hearth length while maintaining or improving impurity removal efficiency, thereby reducing heating costs and increasing productivity.

The patent changes the flow dynamics parameters by introducing Marangoni convection through selective heating. Instead of extending the hearth length to increase residence time, the system modifies the velocity and circulation patterns of the molten metal through controlled temperature gradients. This parameter change (flow velocity distribution) intensifies the mixing and impurity removal process within a shorter time frame and shorter hearth length, resolving the contradiction between thorough impurity removal and production efficiency.

The patent applies local quality by creating different flow characteristics in different regions of the hearth. Through selective electron beam irradiation along a line from the center toward the downstream side, the system creates a localized temperature gradient that generates Marangoni convection in the downstream region. This localized action reduces flow velocity and creates a recirculation pattern in the impurity-prone area, while allowing faster flow in other regions, thus containing impurities without sacrificing overall pouring efficiency.

The patent applies dynamics by creating a time-varying or spatially-varying flow pattern through controlled heating. The electron beam irradiation along a specific line creates a dynamic temperature distribution that drives Marangoni convection, continuously circulating the molten metal and trapping impurities in the upstream region. This dynamic flow control allows the system to maintain efficient overall flow while creating localized low-velocity zones that prevent impurity escape.