, measures including optimizing charge scrap structure, hot charging, optimizing power supply system, arc-covering foamed slag, furnace door lance oxygen supplying, oil-oxygen fluxing and lining mortar injection technique are adopted in 20t EAF of the special steel works of Laigang, then the tap-to-tap is shortened by 26 mi.

Since the introduction of melting acceleration technique by coal-oxygen injection in the electric are furnace operation the heat supply has changed from partial supply pattern into a new one on a large area and multi point basis, and as a result the syn- chronous melting of furnace charge has replaced the previous mode of gradually melting.