Yang C Cheng

US Patent:

7730753, Jun 8, 2010

Filed:

Feb 6, 2007

Appl. No.:

11/671495

Inventors:

Paul E. Krajewski - Sterling Heights MI, US
Yang T. Cheng - Troy MI, US

Assignee:

GM Global Technology Operations, Inc. - Detroit MI

International Classification:

B21D 22/00
C21D 1/68
B22C 3/00

US Classification:

72 42, 72 39, 72 41, 72 43, 72 46, 148537, 148696, 148703, 148708, 508154, 508155

Abstract:

The hot stretch forming of sheet metal alloys, such as highly deformable aluminum alloy materials, is improved by using a lubricant comprising bismuth between the forming tool and the engaged surface of the sheet metal. A precursor of bismuth, such as bismuth subsalicylate, may be dispersed in a liquid and applied to the sheet metal before the sheet is heated to its forming temperature. Other lubricants such as boron nitride may be combined with the bismuth precursor. The precursor compound is decomposed to bismuth (or bismuth and carbon in the case of bismuth subsalicylate) which lubricates contact between the surface(s) of the sheet and the forming tool during forming and removal of the formed part from the tool.

US Patent:

8266938, Sep 18, 2012

Filed:

Aug 25, 2009

Appl. No.:

12/546767

Inventors:

John R. Bradley - Clarkston MI, US
Paul E. Krajewski - Troy MI, US
Yang T. Cheng - Troy MI, US

Assignee:

GM Global Technology Operations LLC - Detroit MI

International Classification:

B21D 26/14
B21J 5/04

US Classification:

72 56, 72707, 294192

Abstract:

Electromagnetic forming methods suitable for creating surface features on a shape memory alloy are described. Features may be created over a range of scales, including those suitable for the generation of holographic images. Features, images, or patterns may be made capable of reversibly appearing and disappearing as a result of changes in temperature and may include temperature sensitive displays for automotive and other applications.