High temperature workability behaviour of a modified P92 steel

Abstract

The high temperature forming behaviour of a modified P92, type 9% Cr, steel is studied by means of torsion tests. The data obtained from these tests allowed correlation of the number of turns to failure, a measure of ductility, as a function of strain rate and temperature. In addition, the data were correlated by the Garofalo equation with a stress exponent of 4.78 and an activation energy of 390 kJ mol–1. This equation was used to predict the formability behaviour for the rolling process and also to determine the maximum forming efficiency and stability of the steel. A temperature of 1 140 °C is found to give the optimum forming temperature.