Patent ID: 6033499
Filing Date: 2000-03-07
Classification: B21D,C21D,C22F

Abstract:
In the process of forming an age-hardened aluminum alloy sheet by clamping edges of said sheet in a fixed position and stretching said sheet with a punch having a sheet forming surface and a punch radius at the periphery of said forming surface such that said sheet is stretched across said forming surface and around said radius and deformed into conformity with said sheet forming surface, the improvement comprising,identifying (a) the edges of said sheet to be clamped and (b) the area of said sheet to be engaged by said punch surface including the portion of said area to be stretched around said punch radius portion,selectively rapidly heating a region within said area of said sheet to be engaged by said punch but excluding from said heated region said portion to be stretched around said punch radius to temporarily eliminate the age-hardened condition of said region and to thereby soften it as compared to the rest of said sheet and immediately quenching said heated region to room temperature and thereafterengaging said sheet with said punch to deform it into conformity with said sheet forming surface before said heated region regains its age-hardened condition.