Mechanical and Corrosion Properties of Low-Carbon Steel Processed by Cryorolling: Effect of Different Initial Microstructures

In this study, low-carbon steel was fabricated by 70% rolling with ferrite–pearlite and ferrite–martensite as starting microstructures at liquid nitrogen temperature. The samples were characterized for microstructure, crystallite size, strength, and corrosion behaviour by using optical microscopy, X-ray diffraction, tensile test, potentiodynamic polarization, immersion test and electrochemical impedance spectroscopy. The ferrite–martensite starting microstructure has the highest grain aspect ratio (12.86), highest ultimate tensile strength (927.36 MPa), highest yield strength (920.05 MPa), smallest crystallite size (4.80 nm) and elongation (8.08%) than cryorolled sample with ferrite–pearlite structure. Moreover, the sample with initial structure of ferrite–martensite has the highest corrosion resistance.