Liu Zili

Corrosion Performance of High Strength Weathering Steels Under Different Heat Treatment States

The corrosion performance of high strength weathering steel with Cu, Cr micro-alloying under as-rolled, annealed, normalized, and TMCP states was studied. Results showed that the microstructures of steels under as-rolled, annealed and normalized states were composed of pearlite and ferrite. Average grain size of as-rolled steel was the largest, followed by annealed and normalized. The microstructure of TMCP was mainly consisted of martensite. The corrosion potentials of naked steels in TMCP, as-rolled, annealed and normalized states had little difference, but the corresponding corrosion currents were 0.1287× 10−5A•cm−2, 0.4418× 10-5A•cm−2, 0.7364× 10−5A•cm−2 and 1.064× 10−5A•cm−2, respectively. However, the variation tendency of polarization resistance was contrary to the corrosion currents. After two months, the polarization resistance of the TMCP steel decreased to 1304Ω•cm2, but the annealed, as-rolled and normalized steel increased to 1881Ω•cm2, 1561Ω•cm2 and 1068Ω•cm2, respectively. The arrangement of annual corrosion rate from high to low was: normalized, as-rolled, annealed and TMCP steel, and the rule of rust layer from thick to thin was similar.