Production manner null of aluminum alloy board for automobile body sheet

摘要

PURPOSE: To inexpensively produce an Al alloy sheet excellent in formability in the case of using low viscosity lubricating oil by a simple process by subjecting the cold rolled sheet of an Al-Mg alloy having a specified compsn. to process annealing, thereafter subjecting it to final cold rolling by a roll having a specified surface roughness and executing final annealing. ;CONSTITUTION: The ingot of an Al allay contg., by weight, 2.0 to 8.O% Mg and furthermore contg. one or ≥two kinds among 1.5% Fe, l.0% Mn, 0.3% Cr and 0.3% Zr is subjected to hot rolling, is thereafter subjected to cold rolling at ≤20% rolling ratio and is next subjected to process annealing at 320 to 550°C to regulate the recrystallized grain size in the surface layer of the Al alloy sheet to 70 to 300μm, which is successively subjected to final cold rolling by a rolling roll having ≤0.5μm Pa roll roughness to form into a sheet material in which the recrystallized grain size in the sheet surface layer is regulated to 10 to 50μm and the surface roughness Pa to ≤0.5μm, and also, the surface roughness Ra in the case of being applied with 10% stretch is regulated to ≥0.8μm. The Al alloy sheet having high formability under low viscosity lubrication only by ordinary roll finishing can be produced at a low cost without subjecting the surface of the Al alloy sheet to special shot dull finishing.;COPYRIGHT: (C)1996,JPO