Microstructure and Mechanical Properties of Medium Carbon Martensitic Steel after Warm Rolling at Different Temperatures

The effects of rolling temperature on microstructure transformation and mechanical properties of medium carbon martensitic steel were investigated by means of SEM,EBSD and tensile tests. The results show that when sample are subject to 80% deformation,with the rolling temperature increased from 500 ℃to 600 ℃,ferrite grain size increased from 0.51 μm to 0.78 μm,the carbide particle size increased from 40 nm to 200 nm,and the effect of temperature on the carbide particle size was significantly higher than that of ferrite.When the rolling temperature is increased from 500 ℃ to 600 ℃,the tensile strength decreased from 1 029 MPa to 909 MPa,and the total elongation increased slightly.The tensile strength ratio of the experimental steel was between 0.963 9 and 0.983 2 after warm rolling.