Patent ID: 6381827
Filing Date: 2002-05-07
Classification: B23P,F01D,F16B,Y10S,Y10T

Abstract:
A method for maintaining a clamping force between bolted parts while operating at a temperature of 800Â° F. to 1200Â° F., said method including the steps of:selecting an elongated fastener providing a sufficiently large shear area along a shank portion for preventing stripping of threads during high temperature service, the fastener having a stress generator and a connector at opposite ends of said shank portion, the shank portion having a coefficient of thermal expansion similar to a coefficient of thermal expansion of such bolted parts to minimizing differential dimensional changes due to temperature variations, the shank portion having an elastic limit sufficiently great for maintaining a clamping force between such bolted parts throughout a temperature range from ambient temperature to an operating temperature of between 800 degrees F to 1200 degrees F, the shank portion having a creep strength several times greater than the creep strength of such bolted parts at said operating temperature; installing the selected fastener to mechanically join such bolted parts; and operating the stress generator substantially at an ambient temperature to stress the shank portion efficiently within elastic limits thereof to maintain said clamping force at the operating temperature of between 800 degrees F to 1200 degrees F.