ASTM International

EVALUATION OF THE ELEVATED TEMPERATURE TENSILE AND CREEP-RUPTURE PROPERTIES OF 1/2Cr-1/2Mo, ICr-1/2Mo, and I1/4Cr-1/2Mo-Si STEELS
 N DS50

Annotation

This report evaluates the elevated temperature strength and ductility of three low chromium-molybdenum steels that find extensive service at moderately elevated temperatures--up to perhaps 1100°F. Included in the evaluations are previously unpublished test results gathered by the Metal Properties Council, as well as test results previously published in ASTM Data Series DS 6 (1953) (1) and DS 6S1 C1966)(2).

Employing a normalization procedure that involves ratioing the elevated temperature strength of a particular test lot to the room temperature strength of that same lot, and applying the method of least squares, trend curves depicting the characteristic temperature variations of yield and tensile strengths have been developed.

The rupture and secondary creep rate data have been evaluated by both direct isothermal interpolation or extrapolation, and by time-temperature parameter, to establish the temperature dependencies of the average and minimum stresses to cause rupture in 1000, 10,000 and 100,000 hours and of average and minimum stresses to cause secondary creep rates of 0.1 and 0.01 percent per 1000 hours.

Elongation and reduction of area data are included for- both the short time tensile tests and for the rupture tests.

Several summary figures immediately following this abstract, Figs. 1-3, show the temperature dependence of strength properties for the three grades of steel evaluated in this report. In these figures, the yield and tensile strengths trend curves have been computed from the respective ratio trend curves so that they correspond at room temperature to the specified minimum values of common ASTM product specifications.