METHOD FOR MANUFACTURING HOT DIP ALUMINUM COATED STAINLESS STEEL SHEET BY INDIRECT HEATING

摘要

PURPOSE: A method for manufacturing hot dip aluminum coated stainless steel sheet is provided in which operation is stably performed in annealing process or cooling process by suppressing a chromium oxide film to the maximum through preheating process adopting indirect heating instead of direct fired furnace. CONSTITUTION: In a method for continuously plating stainless steel sheet in a hot dip aluminum coating pot(3), the method for manufacturing hot dip aluminum coated stainless steel sheet(4) by indirect heating comprises a preheating step of indirectly heating the stainless steel sheet(1) in preheating zone(30) at an oxygen concentration of 100 ppm or less and dew point temperature of -40 deg.C or less under the reduction gas atmospheric conditions; annealing step of annealing the preheated stainless steel sheet in annealing zone(50) at a reduction gas atmosphere; and cooling step of cooling the annealed stainless steel sheet in cooling zone(60) to a temperature of the hot dip aluminum coating pot or more at a reduction gas atmosphere, wherein the preheating step is performed in the temperature range of 400 to 500 deg.C, the annealing step is performed at an oxygen concentration of 50 ppm or less and dew point temperature of -30 deg.C or less, wherein the cooling step is performed at a dew point temperature of -20 deg.C or less, and wherein the stainless steel sheet is cooled to a temperature of 680 deg.C or more in the cooling step.