Formation mechanism and control of pinhole defects of oxide scale on the surface of base material for cold rolling of DC03
In view of the problem of pinhole defect of oxide scale appeared on the surface of the hot rolled strip after pickling of producing DC03 cold rolled sheet in an enterpris,theoretical and experimental research was carried out in combination with the field.Firstly,it is con-cluded that the pinhole defects of the oxide scale are mainly caused by the fact that the oxide scale is pressed into the strip surface during the finishing rolling.In order to further explore the formation mechanism of this defect,the oxidation kinetics experiment of DC03 was carried out in the laboratory at the temperature of 830-1 080 ℃.The results showed that the oxidation activation energy of the DC03 steel was low,and it was easy to produce thicker oxide scale in the finishing rolling temperature range.Moreover,the proportion of FeO in the oxide scale increased with the increase of temperature,and the plasticity of the oxide scale was improved.When the finishing rolling temperature was low,the oxide scale was broken seriously,and the oxide scale was easily pressed into the matrix,forming the pinhole defect of the oxide scale.However,the plasticity of the oxide scale was gradually improved with the increase of the rolling temperature.When the temperature reached a certain level,the oxide scale could be well deformed with the matrix,so that the oxide scale could maintain a relatively good integ-rity.Based on the above research results,some improvement measures were put forward to improve the rolling speed and strictly control the finishing rolling temperature.The thickness and plasticity of the oxide scale were effectively controlled,and completely eliminate the pinhole defect of oxide scale of base material for cold rolling of DC03.
base material for cold rolling of DC03pinhole defect of oxide scalefinishing temperatureplastic deformation
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