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US 5,671,626 AGranted
Method of drawing a tube
AssigneeGeneral Motors Corporation
InventorSohrab Sadri Lonbani
Life of this patent
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Abstract
The invention includes a method of drawing a tube to reduce its size. The tube is coated with a drawing polymer that includes a styrene acrylate copolymer, a stearate such as ammonium stearate, water, and other additives to enhance lubricity. The tube can be coated at low temperatures such as ambient or from 50.degree.-100.degree. F.
Claims3
A method of drawing a metal tube to reduce its size comprising the steps of:
- applying a drawing polymer solution to the outer and inner surfaces of a metal tube at temperatures ranging from 50.degree.-100.degree. F., said polymer drawing solution comprises a styrene acrylate copolymer and a stearate, said step of applying a drawing polymer solution being conducted without prior pickling or phosphating of the metal tube;
- drawing the coated metal tube through a die to reduce the size of the tube in the range of about 10% to about 40% reduction in area wherein said drawing polymer solution comprises 70-75 weight percent water, 4-9 weight percent styrene acrylate copolymer, and 5-10 weight percent of ammonium stearate.
Dependencies are inferred from the claim text.