New steelmaking process based on cleaner deoxidation technology

In modern long-process steel production, a blast furnace uses materials such as pulverized coal and coke to reduce iron ore, producing carbon-saturated molten iron. In the converter, molten iron and scrap steel are used as raw materials, and a large amount of oxygen is blown in to achieve decarburization, dephosphorization, and temperature increase, thus obtaining molten steel with high oxygen content. In the refining process, ferroalloys must be added to remove excess oxygen from the initial molten steel. However, this process will cause the deoxidizer added to the molten steel to combine with oxygen, forming a significant amount of oxide inclusions that cannot be completely removed. Furthermore, it requires a substantial consumption of deoxidizing alloys, which increases the carbon emissions in the steel production process. To address these issues, our research team, after years of research, has developed a series of cleaner deoxidation technologies, including carbon deoxidation of molten steel, hydrogen deoxidation of molten steel, and waste plastics deoxidation of molten steel. This technology has undergone multiple hot-state experiments in the laboratory and has been applied in industrial production of non-aluminum deoxidized bearing steel, yielding exce1llent results. This study, through thermodynamic calculations and laboratory hot-state experiments, validated the deoxidation limits of carbon under atmospheric and vacuum conditions. It demonstrated that hydrogen also has the capability to reduce the total oxygen content in molten steel to below 10×10−6. The research also analyzed the deoxidation mechanism and consumption of polyethylene. After adopting cleaner deoxidation technology, the oxygen content of bearing steel can be controlled at 6.3×10−6, reducing the inclusion density by 74.73% compared to aluminum deoxidized bearing steel. In the final deoxidation stage, the use of the cleaner deoxidation technology in non-aluminum deoxidized bearing steel reduces the oxygen content to below 8×10−6. The main composition of oxide inclusions is silicate, along with small amounts of spinel and calcium aluminate. The oxygen content in gear steel can be reduced to 7.7×10−6, with a 54.49% reduction in inclusion density, and it essentially contains no inclusions larger than 5μm. High-speed steel can achieve a total oxygen content as low as 3.7×10−6.