METHOD FOR MANUFACTURING ALUMINUM ALLOY SHEET TO BE FORMED SUPERIOR IN HEM BENDABILITY AND SURFACE QUALITY

摘要

PROBLEM TO BE SOLVED: To provide a method for manufacturing a 6000 series aluminum alloy sheet to be formed, which has superior paint bake hardenability, superior hem bendability, and superior surface quality free from ridging and orange peel after being formed.;SOLUTION: The aluminum alloy includes Mg, Si, and one or two elements of Mn and Cr so as to satisfy the expression of 0.1%≤2Mn+Cr≤0.3%. The manufacturing method comprises heating the slab of the above aluminum alloy to 480°C or higher but lower than 580°C, rolling it one or more times with a rolling reduction of 30% or higher at 350 to 500°C, then rolling it one or more times with a rolling reduction of 70% or lower at 200 to 400°C, cooling it, cold-rolling it with a total rolling reduction of 30% or higher, holding it at a solution heat treatment temperature of 480°C or higher but lower than 580°C for 5 minutes or shorter, cooling it to 50°C or higher but lower than 150°C at 2°C/s or lower, and subjecting it to stabilizing treatment. The above slab may contain one or more elements from among Cu, Ti, B, Fe and Zn, as needed.;COPYRIGHT: (C)2005,JPO&NCIPI