Historical overview on the development of converter steelmaking from Bessemer to modern practices and future outlook

Converter steelmaking is the main stage in ore-based production using blast furnace hot metal and steel scrap as charge materials. Over 70% of steel is produced via basic oxygen converters today. The converter process was developed in the middle of nineteenth century by blowing air through pig iron melt for decarburisation. The subsequent innovation was basic lining and the Thomas process. The next problem, the switch from air to oxygen was hard and did not succeed on an industrial scale until the 1950s when oxygen blowing via top lance was developed. Oxygen bottom blowing was then solved by applying annular nozzles with hydrocarbon cooling. Current technologies combine benefits of top and bottom blowing in hybrid processes. In this review, the history of converter processes is briefly surveyed. Recent progress and challenges, e.g. better utilisation of post combustion for scrap melting, are discussed. Continuous converting and the future role of converter process are also highlighted.