| 摘要 |
PURPOSE:To suppress the surface oxidation of a cold rolled steel plate during cooling by using a water refrigerant having specific vapor pressure under specific conditions in cooling the steel plate soaked in a reducing atmosphere in continuous annealing of said steel plate. CONSTITUTION:In cooling a steel plate soaked in a reducing atmosphere by introducing the same into a cooling zone, a water refrigerant contg. such materials that make the vapor pressure of their aqueous soln. at a 20 deg.C temp. and a 1mol/kg concn. <=18mm.Hg, for example, one or >=2 kinds of LiOH, LiCl, NaOH, KOH, NaCl is used. The concn. thereof is kept at about 0.1-10wt%. Further, in order to make the oxidation suppression during cooling of the steel plate more effective, it is desirable to stick one or more kinds of alkali metal compounds, alkaline earth metal compounds, B compounds, Al compounds, Si compounds, metallic Ni and their compounds, and metallic Sn on the front and rear surfaces of the steel plate prior to annealing. |
