Patent ID: 6266991
Filing Date: 2001-07-31
Classification: B23P

Abstract:
A method to coldwork holes at ambient temperatures of manufacturing shops, utilizing superelasticity property of shape memory alloys, comprising the steps of:(a) inserting a seamless sleeve made of a shape memory alloy having a superelasticity property into a hole in an associated workpiece, whose diameter is sufficiently larger than the outside diameter of said sleeve;(b) placing a mandrel having a diameter at one end sufficiently larger than the inside diameter of said sleeve, the combined diameter of said mandrel and wall thickness of said sleeve being greater than the diameter of said hole;(c) driving said end of said mandrel through and out of said sleeve to expand said sleeve and said hole, thereby coldworking the material around said hole; thereafter said sleeve at ambient temperature shrinking to an outside diameter sufficiently smaller than the diameter of coldworked said hole as to ease the removal of said sleeve out of coldworked said hole.