Method for producing a sheet metal or strip and a sheet metal or strip produced using same

Abstract

A method for producing a sheet metal or strip and a sheet metal or strip produced using this method are described. For a comparatively high gloss level and a comparatively high durability, it is proposed for the sheet metal or strip made of an aluminum alloy of the EN AW-5xxx type to have a cold-rolled structure having a grain structure that is elongated in the rolling direction, with grains whose grain aspect ratio AIl=ll(0°)/ll(90°) is ≥10, more particularly ≥15, measured according to ASTM E112-13.

1 . A method for producing a sheet metal or strip, wherein the method comprises the following steps in the indicated order:
 Hot rolling a rolling ingot made of an aluminum alloy of EN AW-5xxx type and with an initial thickness to a hot-rolled strip or sheet metal with a hot strip thickness,   Intermediate annealing of the hot-rolled strip or sheet metal with a first holding temperature, which is ≥a solvus temperature of Mg-containing precipitates of the aluminum alloy and is<a melting temperature of the aluminum alloy, and subsequent quenching of the intermediate annealed strip or sheet metal,   Cold rolling the quenched strip or sheet metal to a final thickness in a plurality of rolling passes, optionally with a pickling step as an intermediate step between the plurality of rolling passes, wherein the cold rolling is carried out with a cold rolling degree of ≥70% of a hot strip final thickness to the final thickness, and   Final annealing of the cold-rolled sheet metal or strip with a second holding temperature<a recrystallization temperature of the aluminum alloy.   
     
     
         2 . The method according to  claim 1 , wherein the first holding temperature is in a range from ≥400° C. to ≤600° C. 
     
     
         3 . The method according to  claim 1 , wherein the intermediate annealing has a first holding time in a range from >2 seconds(s) to 6 minutes (min). 
     
     
         4 . The method according to  claim 1 , wherein the second holding temperature is in a range from 200° C. to 280° C. 
     
     
         5 . The method according to  claim 1 , wherein the final annealing has a second holding time of ≥6 hours (h) and/or ≤30 h. 
     
     
         6 . The method according to  claim 1 , wherein the final annealing of the sheet metal or strip is carried out under inert gas. 
     
     
         7 . The method according to  claim 1 , wherein the hot rolling is carried out with a hot rolling degree of ≥95% or greater from the initial thickness to the hot strip thickness. 
     
     
         8 . The method according to  claim 1 , wherein the sheet metal or strip is hot-rolled to the hot strip thickness in a range from 5 to 12 mm. 
     
     
         9 . The method according to  claim 1 , wherein in the cold rolling, the sheet metal or strip is rolled in rolling passes with decreasing roll roughness of the rolls in each rolling pass. 
     
     
         10 . The method according to  claim 1 , wherein the sheet metal or strip is cold-rolled to the final thickness in a range from 0.5 to 1.5 mm. 
     
     
         11 . The method according to  claim 1 , wherein before the hot rolling, the rolling ingot is kept at a heating temperature ≥400° C. for at least one hour. 
     
     
         12 . A sheet metal or strip made of an aluminum alloy of EN AW-5xxx type with a cold-rolled structure that has a grain structure that is elongated in a rolling direction, with grains whose grain aspect ratio AI l = l   l(0°) / l   l(90°)  is ≥10, measured according to ASTM E112-13. 
     
     
         13 . The sheet metal or strip according to  claim 12 , wherein  l   l(90°)  is <20 μm. 
     
     
         14 . The sheet metal or strip according to  claim 12 , wherein the structure is not recrystallized in an H2X state. 
     
     
         15 . The sheet metal or strip according to  claim 12 , wherein a surface of the strip or sheet metal has a gloss level of ≥50 GU, measured according to ÖNORM EN ISO 7668 at an angle of 20° and transverse to the rolling direction. 
     
     
         16 . The sheet metal or strip according to  claim 12 , wherein the sheet metal or strip has a surface layer that is polished or is polished and anodized, and wherein a surface of the strip or sheet metal has a gloss level of ≥60 GU, measured according to ÖNORM EN ISO 7668 at an angle of 20° and transverse to the rolling direction. 
     
     
         17 . The sheet metal or strip according to  claim 12 , wherein the aluminum alloy contains
 from 0.50 to 1.1 wt % magnesium (Mg),   from 0.01 to 0.30 wt % silicon (Si),   from 0.01 to 0.7 wt % iron (Fe),   
       and optionally, elements from the following group, either individually or in combination:
 up to 0.20 wt % manganese (Mn) 
 up to 0.20 wt % copper (Cu) 
 up to 0.10 wt % chromium (Cr) 
 up to 0.25 wt % zinc (Zn) 
 up to 0.01 wt % titanium (Ti) 
 up to 0.03 wt % gallium (Ga) 
 up to 0.05 wt % vanadium (V) 
 
       and residual aluminum as well as inevitable production-related impurities, each totaling a maximum of 0.05 wt % and all together totaling at most 0.15 wt %. 
     
     
         18 . The method according to  claim 1 , wherein the first holding temperature is greater than or equal to a solvus temperature of Mg 2 Si type precipitates. 
     
     
         19 . The method according to  claim 1 , wherein the cold rolling is carried out with a cold rolling degree of ≥75% of the hot strip final thickness to the final thickness. 
     
     
         20 . The sheet metal or strip according to  claim 12 , wherein the sheet metal or strip is made of an aluminum alloy of the EN AW-5xxx type with a cold-rolled structure that has a grain structure that is elongated in the rolling direction, with grains whose grain aspect ratio AI l = l   l(0°) / l   l(90°)  is ≥15 measured according to ASTM E112-13.