A Study on Formation of Island Shaped Surface Oxide in AHSS Steels




Abstract: The present study discusses the morphology of surface oxides formed on AHSS Steels during continuous annealing. AHSS steels show poor galvanizability due to the surface oxide formed by silicon and manganese diffusion during annealing. Many studies have been made to enhance galvanizability by changing the morphology of the surface oxide to island-shape . It is well known that the island shaped surface oxide is relatively favourable for galvanizability due to the exposed iron between the islands. This study therefore aims to investigate the morphological changes of surface oxides in different conditions such as alloying element ratio, dew point temperature and pre-coating. The result shows that the island shaped oxide can be obtained by increasing manganese content in the chemical composition of the steel or applying pre-coating before annealing. Meanwhile, high dew point temperature up to +10℃ does not affect the morphology

Authors: Wonhwi Lee

Keywords: Surface oxidation, galvanizing, Dew point, pre-coating

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5 pages


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