| 摘要 |
PURPOSE:To suppress the oxidation of steel belt surface and to simplify the succeeding reduction process by a method wherein the oxygen partial pressure in combustion produts in a heating furnace is controlled to a specific range when heating a steel belt in a direct firing heating furnace. CONSTITUTION:When heating a steel belt in a direct firing heating furnace to a temperature over 300 deg.C, the oxygen partial pressure P (ppm) in combustion products is controlled to satisfy the equation log10P<=2.1+(T-600)/250 where T( deg.C) is the heated steel temperature. This suppresses the oxidation of steel surface and facilitates the reduction of formed oxide. As a result, excellent heating efficiency inherent to the direct firing heating method is effectively utilized, allowing the use of a compact reduction zone installation and providing a steel belt having excellent surface appearance. |
