APPLICATION OF THE CALPHAD METHOD FOR FERRITIC BOILER STEELS

Abstract

Some applications of the CALPHAD method are shown with reference to seamless tubes and pipes for high‐temperature service in power plants. The focus is on concepts on the improvement of creep strength. In view of developing or improving steels for the application in conventional power plants, various elements have been tested with respect to a controlled precipitation of chromium carbides, carbonitrides and the intermetallic Laves phase.The kinetic simulations are focussed on diffusion-controlled transformations during heat-treatment and application in the power plant. A key-issue is to include important aspects such as nucleation density (in terms of pre-defined cell sizes of the model), growth, and dissolution of precipitates.