Effect of temperature in intercritical treatment on microstructure,tensile properties and hardness in dual phase ST52 steel

Dual phase ferrite-martensite steels are low alloy steels with high strength that have shown excellent ductility during tensile. it's microstructure consisting of a soft ferrite matrix with hard martensite islands at the grain boundaries. in this study the effects of different intercritical annealing temperatures over mechanical properties of dual phase steel st52 have been studied. for this purpose ae1 and ae3 temperatures are mathematically calculated on basis of interaction among chemical composition,anneal temperature and speed of critical cooling rates. based on observed microstructure,increase in anneal temperature,decrease strain follow necking. this matter is related to increase of martensite volume fraction and suitable sites for crack nucleation. the best mechanical proprieties have been seen from specimen that have been annealed in 770 °c for 105 min and water quenched. © 2016.