| It is well know that the steel corrosion and protection is a big problem puzzling iron and steel industry. Every year, the metal yearly output of approximately a quarter to a third have been discarded by corrosion. Due to the surface corrosion of steel wire rolled and deposited in the air, the quality of steel wire will be decreased, meanwhile, the waste of material will be resulted. In the process of rolling machining and exposure to air, the hot-rolled wire will inevitably be formed a thin oxide scales on the surface. In the following machining of the hot-rolled wire, it's necessary to remove the oxide scale. However, the oxide scale can be used against kinds of corrosion in the saving and transferring process before the next working procedure. Thus, it is significant for industrial manufacturin to research the oxide scale of composition, compacting and antisepsis capability.In this paper, the material component and morphology of oxide scale were respectively investigated by using the infrared absorption spectroscopy and SEM. Additionally, the anti-corrosive performance of steel scale on wire rod was also be researched by using the electrochemical potentiodynamic polarization curves and accelerated corrosion test. Comparing the oxide scale with different surface quality, a rule of anti-corrosive performance of steel scale was summarized by researching the influence of scale thickness, tightness and combines of substrate and steel scale on the anti-corrosive performance of steel scale. The results indicate that the surface quality of oxide scale can play an important role in effecting the anti-corrosive performance in the condition of constant air condition, deposited environment and material component. The high surface quality of oxide scale, including the thickness, well tightness and binding force between substrate and steel scale, can enhance the anti-corrosive performance of steel scale on wire rod.Due to the cooling process is an important effect on the surface quality of steel scale on wire rod, the influence of parameters in the process of producing the hot-rolled wire rod on corrosion resistance of iron oxide scale, such as the heating temperature, cooling rate and the cooling temperature was investigated by using the thermal simulator of GLEEBLE1500. The different cooling temperature of 910℃, 880℃and 850℃and cooling rate of 0.5℃/S,1℃/S,2℃/S and 3℃/S was respectively adopted in our experiments. Moreover, the scale composition was primarily analyzed through XRD. The scale surface feature, thickness and tightness were observed through SEM. The anti-corrosive performance of steel scale was investigated by accelerated corrosion test. The results indicate that when the temperature and cooling rate in the cooling process is 850℃and 2℃/S, the oxide scale with optimal thickness, tightness and binding force between substrate and steel scale can be obtained. The cooling temperature of 910℃and 880℃can increase the thickness of oxide scale and make the oxide scale crack. Moreover, the thickness of oxide scale also can be increased in the cooling rate of 0.5℃/S and 1℃/S. when the cooling rate is 3℃/S, the thickness of oxide scale will be decreased and lose the performance of corrosion resistance.Based on the above research, the practical production of steel wire rod was also be ameliorated. The results indicate that the surface quality of oxide scale including optimal thickness, tightness, the anti-corrosive performance, less crack, and binding force between substrate and steel scale, can be improved in the optimal process of rolling temperature at 880℃and cooling temperature at 860℃.
|
PDF Full Text Request