Correlation between creep and hot tensile behaviour for 2.25Cr-1Mo steel from 500oC to 700oC Part 1: An assessment according to usual relations involving stress, temperature, strain rate and rupture time

Abstract

Hot tensile and creep tests were carried out on 2.25Cr-1Mo steel at 9 temperature levels between 500°C and 700°C, using 5 different crosshead speeds, namely: 0.01 - 0.25 - 1.0 - 5.0 and 20 mm/min, and 17 levels of stress for creep from 34 to 414 MPa. The experimental work involved the analysis of data from 30 hot tensile tests and 50 constant load creep tests, with rupture times varying from 2 to about 1300 hours. Each of these set of data were analyzed separately according to their own methodologies, but an attempt was made to find a correlation between them. A new criteria is proposed for converting hot tensile data to creep data, which makes possible the analysis of the two kinds of results according to the Norton, Zener-Hollomon, Arrhenius and Monkman-Grant relations. The results shows remarkable compatibility, indicating consistent transition from the region of power-law to exponential creep behaviour.