Phase-field simulation of steel microstructure changes during welding process coupled with CCT diagram

Abstract

Continuous cooling transformation (CCT) diagram is useful for understanding phase transformations from austenite to ferrite, pearlite and bainite in steel. CCT diagram is also important to estimate and control the final microstructures produced by complex thermal cycle during welding process. In particular, a phase-field method has been applied to simulate the microstructure changes in the Heat-Affected Zone (HAZ) that is the area heated just below the melting point. In this study, we proposed an integrated microstructure simulation system which predicts the microstructure developments in HAZ by combining multi-phase-field method and CCT diagrams. This simulation system provides an efficient materials design framework that would be able to continue to grow even in the future. The output microstructure data calculated from the system will be expected to contribute accurate mechanical properties of welding steel.