Research On Microstructure And Structural Transformation In Control Cooling Of Oxide Scale On High Carbon Steel Wire After Rolling

The thickness,microstructure and appearance of iron oxide scale formed on the surface of high carbon steel wire rod after pinning on the Stelmor cooling line will affect the use of downstream users.In order to improve the performance of wire descaling,obtain the appropriate scale organization is necessary.By means of formulating different heating systems and cooling process,obtaining samples with different microstructure.Scanning electron microscope was used to observe the microstructure of oxide scale,and analyze the relationship between the microstructure of the oxide scale and the process of heating and cooling,providing the basis for the control of iron oxide in actual production.Isothermal experiments have found that the thickness of oxide scale increases with the increase of oxidation temperature,and the higher the temperature,the faster the oxidation rate.In the high temperature section,the formation rate of FeO is much larger than that of Fe₃O₄,The oxide scale is mainly composed of FeO layers.When the temperature is reduced to below 600?,the formation rate of FeO is reduced and decomposed.The content of it in oxide scale was gradually decreased.The study also found that Fe₃O₄ proeutectoid organization firstly separate out near the junction of FeO and Fe₃O₄ FeO with high oxygen content,and a large amount of Fe₃O₄ appear at 400? to 500? temperature range.The continuous cooling experiment simulates the Stelmor cooling process.The study found that a large number of FeO grown at high temperature region above 850?.With the decrease of temperature,especially at 350-650?,the number of FeO production was significantly reduced.The slower the cooling rate,the greater ratio of the Fe₃O₄ layer,accompanied by a small amount of Fe₃O₄ proeutectoid organization.According to the experimental data of isothermal and continuous cooling experiments,the prediction model of thickness and each group layer thickness ratio was established under the conditions of isothermal and continuous cooling.The regression significance level of model was higher and can be used to forecast and calculation in production process.On the basis of laboratory research,this paper also put forward the improvement experimental program for Wuhan Iron and steel plant production line.By adjusting the spinning temperature and Stelmor cooling process parameters,Which had better effect in removing red rust,increasing the thickness and improving microstructure.