Computational design of UHS maraging stainless steels incorporating composition as well as austenitisation and ageing temperatures as optimisation parameters

Abstract

An extended integral alloy design approach for the development of new ultra high strength maraging steels is presented, which incorporates not only chemical composition effects but also criteria accounting for the influence of the entire heat treatment. The approach considers the desired strengthening precipitates formed during the final ageing treatment as well as undesirable equilibrium phases present during the preceding high temperature homogenisation treatment. The results are compared with the predictions of a previous model, which considered the combination of composition and final precipitation tempering stage only.

Keywords:

• maraging steels
• composition
• precipitation
• carbide
• δ-ferrite
• thermodynamics
• genetic algorithm
• alloy design

Acknowledgement

This research was carried out under the project number MC5.04192 in the framework of the Research Program of the Materials Innovation Institute M2i (www.m2i.nl), the former Netherlands Institute for Metals Research.