Low-carbon steels manufactured by circulating flow vacuum degassing process

Summary

The circulating flow vacuum degassing equipment installed in the open-hearth furnace shop of the Hirohata Works, Fuji Iron & Steel Co., has so far produced 110,000 metric tons of ingots. Its operations has been carried on steadily without any mishaps, and this process is now absolutely necessary to produce certain grades of steel in the Works. Most of the ingots produced by this process are deoxidized by C-O reaction under vacuum from low carbon open steels. The analyses of these steels are the same as those of the conventional rimming steel, except for carbon content, or to be more specific, they contain no deoxidizing elements such as aluminum and silicon. The ingot structure of these steels shows the characteristics of killed steel, and has very slight segragation while their degree of cleanliness is very high. The cold-rolled products from these ingots have surface qualities as good as those of the conventional rimming steel and have somewhat better mechanical properties. The enamelling properties, moreover, are excellent.

Aluminum killed deep drawing steel, produced by adding aluminum onto the degassing vessel, has closely controlled analysis of aluminum in steel and has fewer sliver defects. Thus, it may be said that we have actually realized almost all of the imaginable merits of vacuum degassing utilizing the circulating flow vacuum degassing process.