VD vacuum refining furnace is mainly used for secondary deep refining of molten steel, mainly targeting steel grades with high gas content requirements. By using vacuum treatment to achieve degassing, deoxidation, desulfurization, and removal of inclusions in molten steel, combined with weak argon stirring, a high alloy yield can be achieved. The VOD vacuum refining furnace can achieve oxygen blowing decarburization under vacuum conditions and carbon deoxidation under vacuum conditions. It is an external refining equipment for the smelting of high chromium stainless steel, pure iron, and nickel (cobalt) alloys. The process can form a dual connection with the converter or electric arc furnace.