Aluminium alloy sheet product with improved surface aspect

Abstract

The invention relates to a rolled aluminum-based alloy product for cosmetic packaging comprising, (in weight %): Mn 1.0-1.5, Mg 0.2-0.6, Si 0.2-0.6, Fe 0.1-0.7, Cu 0.05-0.3, Cr 0-0.1, Zn 0-0.3, Ti 0-0.15, other elements ≤0.05 each and ≤0.15 total, remainder Al, wherein the fraction of Al(Fe,Mn)Si phase is at least 50%. The invention also related to a process for the manufacture of a rolled aluminum-based alloy product comprising the steps of: a) casting an ingot with a composition according to the invention; b) homogenizing the ingot at a temperature of at least 480° C.; c) hot rolling said homogenized ingot to a hot-rolled intermediate product; d) cold rolling said hot-rolled intermediate product to a cold-rolled intermediate product; e) recrystallization annealing of the cold-rolled intermediate product; f) cold rolling the annealed cold-rolled intermediate product to a cold-rolled product at final thickness; g) recovery annealing the cold-rolled product at final thickness. The products of the invention are particularly useful for cosmetic packaging, preferably for containers such as bottles, cups, tubes, holders, with a matt surface aspect.

1 . A rolled aluminum-based alloy product for cosmetic packaging comprising, in weight %:
 Mn 1.0-1.5,   Mg 0.2-0.6,   Si 0.2-0.6,   Fe 0.1-0.7,   Cu 0.05-0.3,   Cr 0-0.1,   Zn 0-0.3,   Ti 0-0.15,   other elements ≤0.05 each and ≤0.15 total, remainder Al,   
     
     
         2 . A rolled product according to  claim 1  wherein the fraction of Al(Fe,Mn)Si phase, defined as the total 2D surface of all identified quaternary particles divided by the total 2D surface of all detected particles, is at least 50%. 
     
     
         3 . A rolled product according to  claim 1  wherein the Si content, in weight % is optionally at least 0.20 or optionally 0.22 and/or the Si content does not exceed 0.5 or optionally 0.4 or optionally 0.35. 
     
     
         4 . A rolled product according to  claim 1  wherein the iron to silicon weight ratio is less than 2, optionally less than 1.95 or optionally less than 1.9. 
     
     
         5 . A rolled product according to  claim 1  wherein the Ti content in weight % is at least about 0.01 and optionally at least about 0.02 and/or up to 0.06 or optionally up to 0.05. 
     
     
         6 . A rolled product according to  claim 1  wherein, in weight %, the Cr content is less than 0.04 and/or the Zn content is less than 0.04. 
     
     
         7 . A rolled product according to  claim 1  wherein the grain size in the L and LT directions is less than 75 μm and optionally less than 65 μm with an aspect ratio less than 2.0 and optionally less than 1.8. 
     
     
         8 . A rolled product according to  claim 1  wherein the tensile yield strength in the LT direction is at least 155 MPa optionally at least 160 MPa, the ultimate tensile strength in the LT direction is at least 185 MPa and optionally at least 190 MPa, the elongation A50 is at least 5% and optionally at least 6% and the earing is less than 4.3 and optionally less than 4.0. 
     
     
         9 . A rolled product according to  claim 1  wherein after etching and anodizing treatment, the surface of the product is rated 0 or 1. 
     
     
         10 . A process for manufacture of a rolled aluminum-based alloy product  claim 1  comprising:
 a) casting an ingot comprising, (in weight-%) 
 
       Mn 1.0-1.5, 
       Mg 0.2-0.6, 
       Si 0.2-0.6, 
       Fe 0.1-0.7, 
       Cu 0.05-0.3, 
       Cr 0-0.1, 
       Zn 0-0.3, 
       Ti 0.01-0.15, 
       other elements ≤0.05 each and ≤0.15 total, remainder Al,
 b) homogenizing the ingot at a temperature of at least 480° C.; 
 c) hot rolling said homogenized ingot to a hot-rolled intermediate product; 
 d) cold rolling said hot-rolled intermediate product to a cold-rolled intermediate product; 
 e) recrystallization annealing of the cold-rolled intermediate product; 
 f) cold rolling the annealed cold-rolled intermediate product to a cold-rolled product at final thickness; 
 g) recovery annealing the cold-rolled product at final thickness. 
 
     
     
         11 . A process according to  claim 10  wherein the homogenizing temperature is at least 520° C., optionally at least 550° C. and optionally at least 605° C. 
     
     
         12 . A process according to  claim 10  wherein the hot rolling entry temperature of said homogenized ingot is at least 400° C. and optionally at least 450° C. and/or the hot rolling exit temperature is at least 350° C. and optionally at least 380° C. 
     
     
         13 . A process according to  claim 8  wherein the cold-rolled intermediate product has a thickness between 0.6 mm and 2 mm and/or the final thickness of the cold-rolled product is between 0.2 and 1 mm. 
     
     
         14 . A product comprising a rolled product according  claim 1  for cosmetic packaging, preferably optionally for one or more containers optionally one or more of bottles, cups, tubes, holders, with a matt surface aspect. 
     
     
         15 . The product according to  claim 14  wherein a process to transform the rolled product to a package for cosmetics comprises
 cutting one or more blanks from the rolled product 
 forming the blank, optionally typically by stamping and/or drawing and/or ironing, and/or roll-forming and/or spinning into a container, 
 surface treating said container, optionally to a matt surface, by etching and anodizing. 
 
     
     
         16 . The product according to  claim 14  wherein the surface treating comprises an alkaline etching at a temperature of at least 50° C. and a sulfuric acid anodizing step at a temperature of at least 15° C.