Mechanical Properties and Forming Behavior of a Type 9%Cr Steel Containing 2%W

The possibilities to improve the properties of steels for tubes exposed at high temperatures are explored. The mechanical properties and forming behavior of an experimental casting of type 9Cr-ferritic steels, P92, containing 2%W, are studied. The hardenability was determined by means of continuous cooling diagrams associated with hardness measurements and microstructure observations. Tensile tests from room temperature to 650 degrees C were carried out to determine the variation of the strength and ductility in this temperature range. In addition, Charpy impact tests were conducted to characterize the toughness of the steel and the ductile-brittle transition temperature. Finally, hot torsion tests at various temperatures and strain rates were carried out and the generalized stresses and strains to rupture for each test are determined. With these data forming stability maps were generated to characterize the best forming conditions.