PURPOSE: To prevent the formation of scale on the surface of steel material, and to prevent the environmental pollution due to the generation of black smoke in the heating of steel material in a continuous heating furnace, by controlling the heating zone and the soaking zone to oxidizing and reducing atmospheres respectively.
CONSTITUTION: In heating steel material 2 in a heating zone 4 and a soaking zone 5, the fuel gas in the heating zone 4 is controlled to 1.0W1.5 air-fuel ratio to form oxidizing atmosphere, hereby the fuel is burned completely and the release of black smoke from a stack is prevented. The air-fuel ratio of the fuel gas fed to a burner 7 for the heating zone 4 is controlled to the set value by the feed back of the indication of the analytical meter 8 for oxygen installed in the heating zone 4. In the soaking zone 5, the fuel gas is controlled to 0.5W1.0 air-fuel ratio so as to burn the fuel incompletely to form reducing atmosphere thereby preventing the formation of scale on the steel material 2. The air fed to the soaking zone burner 7' is controlled to the predetermined value by the indication of a CO analytical meter 9 installed in the soaking zone 5.
KOREEDA SHIYOUJI
NAKASUJI KAZUYUKI
