| With the development of railway transportation, it is desirable for theweathering steel with both high strength and atmospheric corrosion resistance.The recrystallization kinetics model is created based on hot deformation ofCu-P-Cr-Ni-Mo-Nb weathering steel, and its microstructures are analyzed.The processes of grain refinement are investigated to improve its strength.The effects of grain sizes on atmosphere corrosion resistance are analyzed. Itmainly includes the following:(1) The double-stage compression tests are performed on the G1eeble-3500simulator under the temperature from850℃to1100℃, strain rate5s-1and inter-pass time from1s to1000s. The effects of the inter-pass time anddeformation temperature on the static softening behaviors are studied.(2) The austenitic static recrystallization activation energy is obtained as256kJ/mol using the least squares method. Based on the recrystallizationkinetics equation, the mathematical model is constructed, and themicrostructures are analyzed.(3) The processes of grain refinement are discussed using the simulatedhot rolling trials based on the hot compression tests. The effects of the startrolling, the finish rolling and the coiling temperature on the microstructuresare discussed.(4) The accelerating corrosive tests are carried out for3trial samples ofdifferent grain sizes with Fl-65dry wet cycle infiltrating corrosion tester. Thesurface and cross sections of rusting layer are discussed. The corrosion rateand depth are calculated with the weight loss method. The PARM273systemis used to measure the polarization curves. The results show that the smallergrain sizes can’t decrease its atmospheric corrosion resistance. |
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