Creep Properties of Steels Utilized in High-pressure and High-temperature Superheater and Steam Pipe Practice. Part III: Revision of Long-time Creep Data for a Carbon Steel Header and a Carbon–Molybdenum Steel Pipe

Abstract

This report is the third of a series dealing with the creep properties of steels.

In Parts I and II^†, estimated temperatures were given for 0·1-0·5 per cent creep in periods of up to 100,000 hours for three carbon, and three carbon-molybdenum, steels, over a selected range of stress; the estimates being obtained by logarithmic extrapolation of creep tests of less than 10,000 hours’ duration.

Part III gives revised temperature estimates for one superheater header carbon steel at 5 tons per sq. in. and for one carbon–molybdenum steam-pipe steel at 6 tons per sq. in., based on the results of creep tests at these stresses lasting 67,000 hours. The extended tests indicate that modifications are necessary in the previously extrapolated temperatures corresponding to 100,000 hours. The two tests are being continued for the full time of 100,000 hours.