Microstructure Evolution and mechanical properties during Cold Rolling and Reverse Transformation in Fe-18 Ni Martensitic Steel

In this study, the effect of cold rolling on the reverse transformation in Fe-18Ni Martensitic alloy were studied by means of microstructure development, mechanical properties by means of tensile and hardness tests. One of promising way to obtain fine grained materials is using reverse martensitic transformation in specific in martensitic steels. This means reverse the alpha phase to the parent phase of gama and quench rapidly. In the present research, the studied alloy was subjected to different amount of cold rolling consisting of 10, 20 and 50%. Then the cold rolled samples was conducted to reverse transformation heat treatment at 700 C for different cycles. It si found that the 50% cold rolled sample followed by reverse transformation at 7000 C for 0 second demonstrated considerable elongation and relatively high strength of 760 MPa and harness of 270 HV. It should be noted that the starting material has strength of 620 MPa and hardness of 223 HV.