High temperature metallic seal

Abstract

A metallic seal includes a cold formed substrate layer and one or more additional layers. At least one of the layers offers improved resistance to high temperature stress relaxation.

Description

CROSS-REFERENCE TO RELATED APPLICATIONS [0001] This application is a divisional and continuation-in-part application of U.S. patent application Ser. No. 10 / 805,764 filed Mar. 22, 2004 and entitled “HIGH TEMPERATURE METALLIC SEAL” which is a divisional application of U.S. patent application Ser. No. 10 / 002,684 (abandoned) filed Oct. 24, 2001 and entitled “HIGH TEMPERATURE METALLIC SEAL” which claims benefit of U.S. Provisional Patent Application Ser. No. 60 / 242,759 filed Oct. 24, 2000 and also entitled “HIGH TEMPERATURE METALLIC SEAL.” The disclosures of Ser. No. 60 / 242,759, 10 / 002,684, and 10 / 805,764 are incorporated by reference herein as if set forth at length.BACKGROUND OF THE INVENTION [0002] This invention relates to seals, and more particularly to metallic seals. [0003] A variety of metallic seal configurations exist. Key metallic seals are commonly held under compression between two opposed flanges of the elements being sealed to each other. Such metallic seals may be used in...

AI Technical Summary

Benefits of technology

[0016] The resultant metallic composite structure can advantageously be fabricated cost effectively to provide complex creep / relaxation-resistant structures for ultrahigh temperature applications. Other high temperature formed structures such as high temperature ducting, combustor liners and components for gas turbine engines can also be fabricated using this technology. Such structures may be advantageous substitutes for more expensive ceramic elements.

Problems solved by technology

Therefore, long-term applications of current metallic seals are generally limited to about 1300° F. because the current cold formable nickel-based superalloys such as INCONEL 718 (Special Metals Corporation, Huntington, W.V.) and WASPALOY (Haynes International, Inc., Kokomo, Ind.

These alloys can not readily be rolled into thinner gauges and cold formed into static seal shapes.

Recently developed mechanically alloyed strips such as MA 754 of Special Metals Corporation and PM 1000 of Plansee AG, Reutte, Austria, with superior high temperature strength characteristics are also very difficult to fabricate into seal shapes.

Some of the refractory alloy strips such as molybdenum base (e.g., titanium-zirconium-molybdenum (TZM)) and niobium base alloys, although cold formable, have poor oxidation resistance above 1200° F.

Therefore, it is believed that no current metallic alloy can readily be cold formed into seal and used at demanding elevated temperature applications requiring enhanced stress relaxation resistance.

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