Inventors:
Moinuddin S. Rashid - Bloomfield Hills MI, US
Kulsum Rashid, legal representative - Bloomfield Hills MI, US
Chongmin Kim - Bloomfield Township MI, US
Edward F. Ryntz - Warren MI, US
Frederick I. Saunders - Addison MI, US
Ravi Verma - Shelby Township MI, US
Sooho Kim - Troy MI, US
Paul E. Krajewski - Sterling Heights MI, US
Assignee:
GM Global Technology Operations LLC - Detroit MI
International Classification:
B21D 26/02
Abstract:
A method is disclosed for stretching magnesium-containing aluminum alloy sheet stock into intricate shapes such as are required in automotive body panels. The sheet stock, at a temperature in the range of about 400 C. to about 510 C. , is stretched under the pressure of a working gas into conformance with the surface of a forming tool. The sheet forming pressure is increased continually in a controlled manner from ambient pressure to a final forming level in the range of about 250 psi to about 500 psi or higher. A portion of the sheet can experience strain rates substantially higher than 10secand the forming of the sheet can be completed within 12 minutes.