Abstract: Based on investigation of factors influencing bottom-blowing effect and tuyeres maintenance methods, the reasonable bottom-blowing intensity schemes were proposed for various steel grades, the suitable thickness of furnace bottom was determined and final slag composition and slag splashing process were optimized. The bottom tuyeres exchange technology was used to realize tuyeres exposing and visualization. Thus the tuyeres life was increased and molten pool stirring effect was improved. Now the bottom blowing system could guarantee carbon-oxygen product to be less than 0.002 7 during 4 000 heats in one service life, and combined blowing rate to 80% with 2 bottom tuyeres.

Key words: converter steelmaking, combined blowing, bottom-blowing tuyeres life, bottom-blowing tuyeres maintenance, carbon-oxygen product