Thermodynamic And Kinetics Analysis Of Oxidation Of Automobile Steel Sheet

With the development of automobile industry, the needing quantity ofautomobile plate is increasing. Therefore controlling the quality of steel plate is very significant, especially the surface quality, but iron oxide seriously influences the surface quality of steel plate, and so it is necessary to analyze the thermodynamics and dynamics of ironoxide.The increased weight of iron oxide of samples is measured byelectronicanalytical balance, Morphology and thickness of iron oxide on surface and section observed by (SEM) and assure the components in iron oxide. The result of Thermodynamic analysis of high temperature oxidation in slab shows that the decreasing the partial pressure of oxygen will reduce the generation of oxide scales in heating and the result of the oxide dynamics shows the oxide law consistent with the parabolic law at high temperature, the function of oxide rate is W^2.21=1.48×10⁵e^-Ea/RT t.The result of oxidation thermodynamic analysis of Blooming states shows that the degree of oxidation will be serious with the time extending and the result of oxidation dynamics shows that the oxide law in blooming consistent with liner law. The function of low carbon steel at high temperature is W=4.53e^-Ea/RT t. The result of hot rolling and coiling shows that the oxide lay will be made of 3-layer structure (Fe₂O₃→Fe₂O₃,Fe₃O₄→Fe₃O→Fe) with rapid cooling while be made of 2-layer structure (Fe₂O₃→Fe₃O₄→Fe) with slow cooling.The best picking of coiling plate is as follows: concentration is 200g/l, temperature is 70℃, time is 45s,so, the acid kinetic function is W^1.2=4.61×10-3e^-Ea/RT t.