Industrial practice of improving quality of 220 mm×260 mm rectangular billet using PMO technology

The former Electric Furnace Plant of Zenith Iron and Steel Group was the first to adopt the Pulsed Magneto-Oscillation (PMO) homogenization technology originally developed by Shanghai University for the continuous casting of 220 mm×260 mm rectangular billets. Taking low-carbon gear steel, medium-carbon tool steel and high-carbon bearing steel as research materials, this paper explores the influence of PMO technology on the internal quality of continuous casting billets via industrial trials. The improvement effect and variation rules of casting speed and superheat on the equiaxed grain ratio of billets are comparatively analyzed. Industrial production results indicate that compared with billets treated merely by final electromagnetic stirring (F-EMS), the equiaxed grain ratio of billets processed with PMO rises by 50% to 100% on average. Such growth becomes more prominent as casting speed and superheat increase. While enhancing the quality of continuous casting billets, PMO technology remarkably expands the process window for continuous casting, offering another key technical approach for the research and engineering application of homogenization technology in continuous casting.