Method of making aluminium rolled product having at least one bright surface

Abstract

The invention concerns a method for cold rolling bright aluminium rolled products and comprises: (a) Providing a first aluminium alloy rolled product (b) Rolling said first product with a rolling mill ( 1 ) having at least one work roll ground to a finish ( 11 ), with a roughness Ra less than 1 μm, and using a rolling lubricant ( 51 ) from a first container ( 2 ) comprising less than 150 mg/L of aluminium debris to obtain a second aluminium rolled product having at least one bright surface, (c) Transferring at least a portion of said rolling lubricant to a second container ( 3 ) (d) Filtering the lubricant from said second container ( 52 ) by using cross flow filtration ( 4 ) through a membrane ( 41 ), to obtain a cleaned rolling lubricant ( 54 ) comprising less than 10 mg/L and preferably less than 5 mg/L of aluminium debris preferentially having a mean diameter of less than 2 μm, (e) Returning said cleaned rolling lubricant ( 54 ) to the first container.

1 . A method for cold rolling bright aluminium rolled products comprising:
 (a) Providing a first aluminium alloy rolled product   (b) Rolling said first product with a rolling mill having at least one work roll ground to a finish, with a roughness R a  less than 1 μm, and using a rolling lubricant from a first container comprising less than 150 mg/L of aluminium debris to obtain a second aluminium rolled product having at least one bright surface,   (c) Transferring at least a portion of said rolling lubricant to a second container   (d) Filtering the lubricant from said second container by using cross flow filtration through a membrane, to obtain a cleaned rolling lubricant comprising less than 10 mg/L and optionally less than 5 mg/L of aluminium debris optionally having a mean diameter of less than 2 μm,   (e) Returning said cleaned rolling lubricant to the first container.   
     
     
         2 . The method according to  claim 1  wherein the water content of the rolling lubricant from said first container is less than 0.1 g/L and the water content of said cleaned rolling lubricant is less than 0.05 g/L. 
     
     
         3 . The method according to  claim 1  wherein the cross flow filtration is carried out through at least one cylindrical ceramic membrane 
     
     
         4 . The method according to  claim 1  wherein the cross flow filtration is carried out with filter membrane assembly having a plurality of filter membranes dynamically moving. 
     
     
         5 . The method according to  claim 1  wherein the rolling lubricant temperature is between 30° C. and 50° C. 
     
     
         6 . The method according to anyone of  claim 1  wherein the cross flow filtration is carried out at a temperature between 50° C. and 100° C. 
     
     
         7 . The method according to anyone of  claim 1  wherein the roughness Ra of said at least one bright surface measured according to standard DIN EN ISO 4288 and/or by using white light interferometry is less than 0.1 μm, optionally less than 0.05 μm, and optionally Ra less than 0.03 μm. 
     
     
         8 . The method according to  claim 1  wherein said rolling lubricant from said first container comprises less than 50 mg/L of aluminium debris. 
     
     
         9 . The method according to  claim 1  wherein said aluminium rolled product comprises an aluminium alloy from the 1XXX, 3XXX or 5XXX series. 
     
     
         10 . The method according to  claim 1  wherein said at least one work roll is ground to a smooth finish with a roughness R a  less than 0.1 μm.