Experimental Research On High-temperature Oxidation Kinetics Of U71Mn Steel In Single Atmosphere

The article studied the oxidation mechanism of U71Mn steel during being heated by analyzing the effect of different oxidizing gases on oxidation of heavy rail steel, in order to optimize the producing system and reduce the oxidation loss.Experiments in which U71Mn steel were oxidized respectively in CO2, H2O and O2in780-1300℃temperature for180min each were examined. Oxidation kinetics curves were drawn by weighting the sample continuously, and oxidation constant rate kp in corresponding condition was calculated, and the influence of different oxidizing gases were analyzed, thus the high temperature oxidation laws and summarized oxidation mechanism of heavy rail steel during heating process were grasped, so as to afford some theoretical basis for optimizing its heating technology.Experimental results showed that oxidation processes of heavy rail steel followed similar kinetics rules under780-1300℃high temperature in atmosphere of oxygen, carbon dioxide or water vapor. As temperatures rose, the oxidation tended to be more serious. The higher the temperature was, the looser the scale was and easier to be peeled down from the body. The oxidation kinetic rate constant kp of heavy rail steel followed the exponential curves with temperature, kp value under the same atmosphere increased with temperature. Under the same conditions of temperature, water vapor caused the largest oxidation, followed by oxygen, and carbon dioxide the weakest. After oxidation for180minutes under temperature above780℃, three kinds of atmospheres all made the sample oxidize over3%; while after180minutes’ oxidation under temperature higher than1000℃, the increased weight got above8%of original sample with carbon dioxide or oxygen present in stove, above10%with water vapor.It can be seen that the presence of O2, CO2and H2O caused significant loss of steel production. Study on oxidation mechanism under high temperature of U71Mn steel, grasping effect of oxidizing factors during whole heating process on oxidation, and optimizing heating system under high temperature of heavy rail steel, had some academic significance and engineering value in improving the steel productivity.