Method for cooling a metal strip during the process of heat treatment
AssigneeDaidotokushuko Kabushikikaisha
InventorsSeiichiro Sekiwa, Kenji Kawate, Hidenobu Jinnouchi
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Abstract
During the process in which a metal strip is moved in a floating condition, the metal strip is first heated, and thereafter cooled and annealed. In cooling the metal strip, the metal strip is cooled so that both edges widthwise thereof are lowered in temperature more quickly than the temperature of a central portion widthwise thereof. The metal strip is cooled in a manner as described whereby a great thermal stress is not introduced in the metal strip and consequently, the metal strip is cooled without being wrinkled.
Claims5
In a method, of heat treatment of a metal strip, which includes the steps of:
- (a) passing the metal strip lengthwise through a heating zone,
- (b) during passage of the metal strip through the heating zone, blowing hot gas onto the strip such that the strip is heated and is also maintained in floating condition by said gas,
- (c) upon emergence of said heated strip from said heated zone, immediately passing said heated strip lengthwise through a cooling zone,
- (d) during passage of the metal strip through the cooling zone, blowing cool gas onto the strip such that the strip is cooled and is also maintained in floating condition by said gas, the cooling of the metal strip being carried out with a cooling gradient which is sufficiently steep to cause in the strip, if cooled substantially equally over its width, a thermal stress greater than the anti-buckling stress of the strip,
- the improvement which comprises cooling the lateral longitudinal portions of the strip more rapidly than a central longitudinal portion thereof, at a rate ensuring that the thermal stress produced in the metal strip is less than the anti-buckling stress thereof.
Dependencies are inferred from the claim text.