The induced martensite transformation in a dual-phase bainitic ferrite-austenite steel during heavy compression was studied by thermodynamic computations. Compression tests were conducted at temperatures of 298 and 573 K on the rectangle samples at the strain rate of 0.001 s(-1). The samples were deformed to 40 and 70% of their original thickness. It was found that 70% compression of the steel at room temperature resulted in transformation of retained austenite to martensite, which is in agreement with thermodynamic calculations. Additionally, heavy compression resulted in the formation of fine grains with high angle grain boundaries which confirms grain refinement.