JPS6415331A - Method for controlling cooling rate of heat treatment furnace - Google Patents

Abstract

PURPOSE:To economically, easily and exactly control the cooling rate of a heat treatment furnace by alternately repeating the blowing of cold wind in the furnace and the heating-up by the recuperation of the material to be treated according to the cooling rate detected by the in-furnace temp. of the heat treatment furnace. CONSTITUTION:The prescribed heating-up and holding of the material to be treated (not shown) are executed by controlling the combustion of a burner 2 by a flow rate controller 6 for combustion in accordance with the measured value of a thermometer 4 along the heat pattern from a heat pattern program setter 5 of the batch type heat treatment furnace 1. The above-mentioned combustion is thereafter stopped by the input of a signal for entry in a cooling zone. The blowing of the cold wind from a cold wind supplying pipe 3 into the furnace is then controlled by a cold wind supply rate controller 8 via a cooling temp. controller 7. The cooling rate is detected by the in-furnace temp. measured by the thermometer 4 in the furnace 1 at this time. The blowing of the above-mentioned cold wind into the furnace is stopped when the cooling rate rises above the set value. The blowing of the cold wind into the furnace is thereafter started when the cooling rate is lowered down to the set value or below by the recuperation of the material to be treated. The in-furnace cooling rate is controlled by repeating the above-mentioned operations.