Mechanical and metallurgical investigation of martensite–austenite constituents in simulated welding conditions

It is well known that the martensite-residual austenite or “M–A” constituent in the heat affected zone (HAZ) is a major factor decreasing the toughness of the welded joint. Up to now, many researches have been devoted to the effect of metallurgical factors and the influence of fraction of M–A on the toughness value. This study entails the influence of thermal cycles and also the chemical composition of the structural steels on the formation and decomposition of M–A constituents by multipass welding conditions simulated on a dilatometer and/or a Gleeble simulator. Additionally, certain experimental results will be presented and the comparative evaluations will be discussed.