At present, the smelting process of stainless steel in the world is mainly divided into one-step, two-step and three-step methods, as well as new integrated production methods. One-step smelting is: molten iron + AOD (argon oxygen refining furnace); The two-step method is: EAF (electric arc furnace) + AOD (argon oxygen refining furnace). The three-step process is: EAF (Electric Arc Furnace) + AOD (Argon Oxygen Refinery) + VOD (Vacuum Refinery Furnace).