Liu H.-Y.,Wuhan University of Science and Technology |
Liu H.-Y.,Hubei Province Key Laboratory of Systems Science in Metallurgical Process |
Liu J.-H.,Panzhihua New Steel and Vanadium Co. |
Li H.-B.,Wuhan University of Science and Technology |
And 3 more authors.
Cailiao Kexue yu Gongyi/Material Science and Technology | Year: 2010
In order to investigate the refining mechanism of microstructures in vanadium-nitrogen steels, the sizes and nature of the inclusions were determined by means of scanning electron microscopy and its attached energy dispersive X-ray analysis unit. A model that described the isothermal growth of idiomorphic ferrite was built based on nucleation of inclusion. Based on this model, the volume fractions of idiomorphic ferrite, which were isothermally produced at 873 K, 823 K for different time after austenization, were calculated and compared with the results of metalloscope measurement. The results indicated that the model can well describe the growth law of idiomorphic ferrite. During the same isothermal time, the volume fraction of idiomorphic ferrite formed at 873 K was greater than that at 823 K. As the transformation temperature decreased, the calculated value of volume fraction of idiomorphic ferrite was smaller than measured value, which is resultant from more VN or V(C, N) particles not only precipitating on MnS inclusions, but also doing outside them as the nuclei of idiomorphic ferrite.
Zuo J.,Control Iron and Steel Research Institute, China |
Chang J.,Control Iron and Steel Research Institute, China |
Liu Y.,Panzhihua New Steel and Vanadium Co. |
Zhang K.-H.,Control Iron and Steel Research Institute, China |
And 2 more authors.
Kang T'ieh/Iron and Steel (Peking) | Year: 2010
Macro-morphology, micro-chemical composition, structure and the mass percent of O/Fe of the red rust iron oxide skin of automotive beam steel were investigated by samples collected in factory. The results show that 2FeO · SiO2 compounds, which are formed by the Si and Fe in steel, were the main reason for the formation of red rust. The mass percent of O/Fe of the red rust iron oxide skin increases gradually from the inside out with more loose structure of the inner surface and outer surface structure more compact. The nature and structure of iron oxide skin are controlled by lowering Si content, reducing the rolling temperature and improving the laminar cooling process, thus avoiding the production of red rust iron oxide skin.