Method and device for controlled straightening and cooling of a wide metal strip, especially a steel strip or sheet metal, running out of a hot rolled strip rolling mill

Abstract

A method and device for controlled straightening and cooling of a wide metal strip, especially a steel strip or sheet metal, running out of a hot rolled strip rolling mill, using pinching rollers arranged in the moving direction of the strip behind vertical double rollers, said pinching rollers producing a tensile stress acting in a longitudinal direction. According to the invention, the range of use of conventional sheet metal cooling systems can be extended to obtain a more even surface of said steel strip with an increased cooling effect. This is achieved by displacing the metal strip or sheet metal between a pre-straightening machine and splash cooling facility in defined conditions of tensile stress by adjusting the tensile stress and by cooling said strip or sheet metal inside said splash cooling facility between successive pairs of pinching rollers and by additionally controlling the tensile stress.

1 . Method for controlled straightening and cooling of wide metal strip or sheet running out of a hot-rolled strip mill, with the use of pinch rolls, which are installed after (in the direction of strip flow) vertical double rolls and produce a tensile stress that acts in the longitudinal direction, wherein the metal strip or sheet is moved from a pre-straightening machine immediately to a splash cooling installation under defined conditions of tensile stress by adjustment of the tensile stress, and that the metal strip or sheet is cooled inside the splash cooling installation between successive pairs of pinch rolls, and the tensile stress is additionally controlled, whereby the metal strip or sheet is plastically deformed prior to entering the cooling installation. 
     
     
         2 . Method according to  claim 1 , wherein the tensile stress is regulated by switching over the speed with respect to each next, last supporting pinching roller with progressive transit of the metal strip or of the sheet. 
     
     
         3 . Method according to  claim 1 , wherein the pinching rollers are fixed at a spacing, wherein a cooling unit is formed between two pinching rollers depending on the spacing. 
     
     
         4 . Method according to  claim 3 , wherein the spacing is adjusted to a half-length of a resulting intrinsic shape for a metal strip or a sheet with smallest thickness at maximum width and high cooling intensity. 
     
     
         5 . Device for controlled straightening and cooling of a wide metal strip or sheet running out of a hot-rolled strip mill, with vertical pairs of double rolls followed (in the direction of strip flow) by pairs of pinch rolls, between each of which a cooling unit is installed, wherein a pre-straightening machine is installed immediately before the pairs of pinch rolls with the cooling units, between which a controllable tensile stress can be produced, whereby the metal strip or sheet is plastically deformed prior to entering the cooling installation, wherein the metal strip or sheet is moved from a pre-straightening machine immediately to the cooling units under defined conditions of tensile stress by adjustment of the tensile stress. 
     
     
         6 . Device according to  claim 5 , wherein the cooling unit has finely adjustable cooling elements and is provided in an outlet for the metal strip. 
     
     
         7 . Device according to  claim 5 , wherein the cooling unit is designed for a high and/or medium cooling output in accordance with a predetermined product spectrum. 
     
     
         8 . Device according to  claim 5 , wherein tensile stresses can also be produced between the last, supporting pinch roll or the straightening roll at the trailing end of the metal strip or of the sheet and the pinch rollers or the straightening rollers at the leading end of the metal strip or sheet. 
     
     
         9 . Device in accordance with  claim 5 , wherein the cooling units are each designed for a high and an intermediate cooling intensity.