Analysis Of Oxidation And Decarburization Mechanism On SK85 Steel Produced By CSP

Compared with traditional hot rolling process,CSP process has its obvious advantage.So the research in medium and high carbon steel produced by CSP process is of great meaning.Decarburization is inevitable on the surface of the steel when the steel is heated in the heating furnace.Appropriate heating temperature and heating time can reduce decarburization efficiently.Spring steel SK85 produced by CSP is the research subject in this paper.The experiment involves in researching how heating temperature and heating time affect the decarburized layer and oxide layer of SK85.The thickness of decarburized layer increased firstly,then reduces and increases again-the heating atmosphere is 16.5%CO2,0.8%O2,13%H2O,69.7%N2 and the heating time remains unchanged in the process-when the heating temperature increases from 900? to 1150?.The thickness of decarburized layer appears the maximum and minimum value at 1050? and 1100? respectively.The thickness of decarburized layer presents a parabolic growth when the heating time increases from15 min to 90 min and the heating temperature is unchanged.When the heating time exceeds 60 min,the thickness of decarburized layer increases at very slow rate.The theoretical thickness of decarburized layer has been set up by using Fick's second law.Then thickness of oxide layer has been measured by metallographic method and advanced weight loss method respectively.Results of weight loss method are more accurate than metallographic method by comparing and analyzing results of two methods.Parameters of K0 and Q2 in computing model of thickness of oxide layer have been figured out by using weight loss method.Finally,the computing model of actual decarburized layer thickness has been set up when the computing model of thickness of oxide layer is taken into consideration.