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U.S. Department of Transportation U.S. Department of Transportation Icon United States Department of Transportation United States Department of Transportation

Archived Rulemaking: Transportation of Natural and Other Gas and Hazardous Liquids by Pipeline; Temperature Limits on Steel Pipe That Has BeenCold Expanded To Meet the Specified Minimum Yield Strength

49-fr-7567.pdf (694.29 KB)

These amendments increase the temperature limit to which steel pipe that has been cold expanded to meet the specified minimum yield strength (SMYS) maybe heated without a reduction in design pressure. The limit now is 6000 F and temperatures above 800' F are needed to remove defects called "hard spots." Research shows that a temperature of 9000 F can be withstood for up to 1 hour without reducing the yield strength of the pipe and that the limit can be safely increased to permit the removal of hard spots and to eliminate a potential cause of hydrogen stress cracking (HSC).

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Last updated: Friday, August 17, 2018