IMPROVEMENT OF MECHANICAL PROPERTIES BY OPTIMIZATION OF Cr AND Mo CONTENTS IN xCr-yMo-9Ni-2Cu-1Ti-1V STEEL

The effects of Chromium and Molybdenum quantities in the range of 9-13 and 3-6 wt% respectively on the microstructural characteristics and mechanical properties of xCr-yMo9Ni-2Cu-1Ti-1V steel was investigated in this research. According to the results obtained in this work, solution treated specimens with lower contents of Cr and Mo had austeniticmartensitic structure. But when increasing these elements, some amount of ferrite was formed. Applying plastic deformation leads to the transformation of austenite to martensite. Increasing Cr content up to 10 wt%, resulted in the improvement of mechanical properties without any substantial change in the microstructure. On the other hand, an increasing Cr content in the range of 11-13 wt% caused a decrease in strength and ductility due to the formation of ferrite in the structure. Besides, Mo showed the same behavior as Cr and when Mo content was 5 wt%, the optimum mechanical properties obtained.