Observation of Oxide Formation for Molten Fe-Cr-C Alloy at a High Carbon Region by Oxygen Top Blowing
- PDF / 12,664,919 Bytes
- 17 Pages / 593.972 x 792 pts Page_size
- 62 Downloads / 165 Views
decarburization process for stainless steel that involves using a converter, having a precise control over temperature is important to decarburize while suppressing the oxidation of Cr. Because Cr can be oxidized as easily as C, a significant amount of Cr is oxidized unless the decarburization process is performed under optimum conditions. To assess the operational conditions for preferential decarburization, indexes considering the blowing conditions and vessel properties have been proposed to estimate the degree of Cr oxidation; these indexes are indexed for selective carbon oxidation (ISCO),[1] balance of oxygen and carbon feeding rate (BOC),[2] Cr oxidation index (CROI),[3] and decarburization potential by chromium-oxide (CRP).[4] However, the degree of Cr RYOSUKE MIHARA, former Student with the Graduate School of Engineering, Tohoku University, Sendai, Japan, is now Staff with JFE Steel Corporation, Kurashiki, Japan. XU GAO, Assistant Professor (Research), SUNJOONG KIM, Assistant Professor, SHIGERU UEDA, Associate Professor, and HIROYUKI SHIBATA and SHIN-YA KITAMURA, Professors, are with the Institute of Multidisciplinary Research for Advanced Materials, Tohoku University, Sendai, Japan. Contact e-mail: [email protected] SHIGERU KANEKO, former Student with the Graduate School of Engineering, Tohoku University, Sendai, Japan, is now Staff with Nippon Steel & Sumikin Stainless Steel Corporation, Yamaguchi, Japan. MIN OH SEOK, Principal Researcher, is with the Technical Research Laboratories, POSCO, Pohang, South Korea. Manuscript submitted June 24, 2015. Article published online January 4, 2016. METALLURGICAL AND MATERIALS TRANSACTIONS B
oxidation is often appraised by using the decrement of Cr content in hot metal; thus, when, where, and in what form the Cr-containing oxides start to form remain unclear. This is important because the behavior and conditions of Cr-containing oxide formation relate to the turning point from preferential decarburization to the oxidation of Cr. Thermodynamics is an important and useful tool to understand the oxidation of Cr from molten steel. In the past few decades, many studies have been conducted to clarify the activities of Cr2O3 in various slag systems,[5,6] as well as the equilibrium relationship between dissolved Cr and O in molten steel.[7,8] However, it is well known that reactions often occur under nonequilibrium conditions in the decarburization process; for instance, the oxidation of Cr was proposed to occur near tuyere when Ar-O2 gas was injected,[9] or in the initial period of decarburization when the content of C was still high as a result of the low temperature.[10,11] Therefore, efforts have been made to establish numerical models to simulate the processes of the simultaneously happened reactions during the decarburization process,[12–17] and these have been helpful to actual operations. Besides the simulations, Wang et al.[18] observed the oxidation of molten Fe-Cr alloy and Fe-Cr-C alloy reacted with O2-CO2 mixtures at constant oxygen partial pressures. But to
Data Loading...
