Method for heat treating a rolling stock made of a heat-treatable aluminum alloy

Abstract

A method and an apparatus are shown for heat treating a rolling stock ( 3 ), particularly a strip, made of an age-hardenable aluminium alloy, particularly an alloy of the 6000 series, wherein the rolling stock ( 3 ) in the process of passing through an apparatus ( 1 ) is fed to a solution annealing operation and a quenching operation, and in a subsequent step the rolling stock ( 3 ) is subjected to hot exposure for age hardening. In order to provide advantageous conditions for the method it is proposed that in a first step during the hot exposure the rolling stock ( 3 ) which is in the process of passing through the apparatus ( 1 ) is heated, whereupon in a further step the heated rolling stock ( 3 ) is further subjected to the hot exposure.

1 . A method for heat treating a rolling stock ( 3 ), particularly a strip, made of an age-hardenable aluminum alloy, particularly an alloy of the 6000 series, wherein the rolling stock ( 3 ) in the process of passing through an apparatus ( 1 ) is fed to a solution annealing operation and a quenching operation, and in a subsequent step the rolling stock ( 3 ) is subjected to hot exposure for age hardening, wherein in a first step during the hot exposure the rolling stock ( 3 ) which is in the process of passing through the apparatus ( 1 ) is heated, whereupon in a further step the heated rolling stock ( 3 ) is further subjected to hot exposure. 
     
     
         2 . A method according to  claim 1 , wherein in a first step of hot exposure the rolling stock ( 3 ) passes through heating ( 11 ) in sections along the length of the rolling stock ( 3 ) over the width thereof and is then subjected to further heat exposure either cut to size or coiled into a coil ( 8 ). 
     
     
         3 . A method according to  claim 1 , wherein the rolling stock ( 3 ) in the process of passing through the apparatus ( 1 ) is heated to one of its age-hardening temperatures, preferably to 160 degrees Celsius. 
     
     
         4 . A method according to  claim 1 , wherein the rolling stock ( 3 ) heated in the first step is further subjected to hot exposure prior to its cooling to a temperature beneath the temperature for hot exposure, especially beneath its lowest age-hardening temperature. 
     
     
         5 . A method according to  claim 1 , wherein the rolling stock ( 3 ) is introduced for further heat exposure into a heatable furnace ( 17 ), especially directly after heating, or is encompassed at least partly by a device for reducing the heat radiation, especially an insulating chamber ( 18 ), and thus is further exposed to heat on the basis of its sensible heat. 
     
     
         6 . A method according to  claim 1 , wherein the solution annealing of the rolling stock ( 3 ) occurs at 450 to 570 degrees Celsius, the quenching of the rolling stock ( 3 ) to beneath 200 degrees Celsius, preferably to room temperature, and the heating in the first step of hot exposure to 100 to 200 degrees Celsius, preferably 160 degrees Celsius. 
     
     
         7 . A method according to  claim 1 , wherein the interval between the end of quenching and the start of the heating for the first step of hot exposure is less than 60 minutes. 
     
     
         8 . An installation for performing the method according to  claim 1 , comprising an apparatus ( 1 ) which comprises both a continuous strip furnace ( 5 ) for solution annealing and also a downstream quenching device ( 7 ) for quenching a rolling stock ( 3 ) which is made of an age-hardenable aluminium alloy, especially an alloy of the 6000 series, and is in passage in the apparatus ( 1 ), and a device for hot exposure of the rolling stock ( 3 ) which comprises a heating ( 12 ) for heating the rolling stock ( 3 ), wherein the apparatus ( 1 ) is associated at least partly to the heating ( 12 ) of the device for hot exposure of the rolling stock ( 3 ). 
     
     
         9 . An installation according to  claim 8 , wherein the heating ( 12 ) associated with the apparatus ( 1 ) belongs to a continuous strip furnace ( 10 ), through which the rolling stock ( 3 ) in passage in the apparatus ( 1 ) will pass as a first step of hot exposure. 
     
     
         10 . An installation according to  claim 8 , wherein the other parts of the device for hot exposure of the rolling stock ( 3 ) are arranged to be separate from the apparatus ( 1 ). 
     
     
         11 . An installation according to  claim 10 , wherein the apparatus ( 1 ) for heating the rolling stock comprises the entire heating ( 12 ) of the device for hot exposure of the rolling stock to hot exposure temperature, especially age-hardening temperature, with the other part of the device for hot exposure of the rolling stock ( 3 ) comprising an insulating chamber partly encompassing the rolling stock for age-hardening the rolling stock ( 3 ).