THE OXIDATION AND REDUCTION BEHAVIOR OF METAL SURFACE IN A FLAME

We examined the possibility whether the indirect heating by radiant tubes in an annealing process at steel industry can be replaced with the direct flame heating without oxidation of the surface. The energy and capital savings are expected by this new-concept technology. The possibility of its practical application has been proved although the successful operating conditions are sensitive to the controlling factors. To realize this concept, the residual oxygen concentration in a flame must be lower than 0.1%(v/v), and the volume ratios of CO/CO2 and H2/H2O in the flame should be over 0.4 and 0.09, respectively.