Investigation of dual phase transformation of commercial low alloy steels: Effect of holding time at low inter-critical annealing temperatures

Dual phase steels are a class of steels characterized by a microstructure consisting of a soft ferrite matrix with hard martensite islands at the grain boundaries. The temperature in the dual phase (alpha+gamma) region and the holding time are two important parameters in the intercritically annealing process. In this study, different grades of commercial low alloy steels have been heat treated to a constant annealing temperature by changing the holding time. It is observed that the effect of holding time is dependent on the steel composition. In this context, a microstructural examination has been carried out using optical, scanning electron microscope and electron probe micro-analysis and hardness values have been determined. (C) 2008 Elsevier B.V. All rights reserved.