Effect of Temperature on the Initial Oxidation Behavior and Kinetics of 5Cr Ferritic Steel in Air
- PDF / 3,667,030 Bytes
- 11 Pages / 593.972 x 792 pts Page_size
- 12 Downloads / 234 Views
TRODUCTION
LOW-CR ferritic steels are used as boiler components in industrial superheater tubes and reheater tubes owing to their low price and excellent combination of properties, including high-temperature strength, good creep resistance, acceptable weldability, and low thermal expansion coefficient.[1,2] At high temperatures, low-Cr steels are always confronted with the issue of oxidation because of the absence of protective Cr2O3 owing to insufficient content of Cr in steels.[2,3] During oxidation, a pore-containing scale can form on the surface of the metal, through which the diffusion rates of metal ions and oxidants simultaneously increase.[4] At higher
ENHUI WANG is with the Collaborative Innovation Center of Steel Technology, University of Science and Technology Beijing, Beijing, China and also with the School of Metallurgical and Ecological Engineering, University of Science and Technology Beijing, Beijing, China. Contact e-mails: houxinmeiustb@ustb. edu.cn, [email protected] JIN CHENG and JIAWEI MA are with the School of Metallurgical and Ecological Engineering, University of Science and Technology Beijing. HUIBIN WU, KUOCHIH CHOU, and XINMEI HOU are with the Collaborative Innovation Center of Steel Technology, University of Science and Technology Beijing, JUNHONG CHEN is with the School of Materials Science and Engineering, University of Science and Technology Beijing, Beijing, China. Manuscript submitted December 4, 2017.
METALLURGICAL AND MATERIALS TRANSACTIONS A
working temperature, breakaway oxidation accompanied by spallation of the protective oxide scale can even occur, which can lead to failure of the material and even cause serious industrial accidents.[5–7] Therefore, improvement of the oxidation resistance of low-Cr ferritic steels is urgently required. Research on oxidation of high Cr (‡ 9 wt pct) ferritic steels has found that alloying elements such as Cr, Si, Ni, Mo, and Mn are crucial for improvement of the oxidation resistance.[8–14] For instance, Lu et al.[8] reported that there is a synergistic effect of Cr and Si, and Si addition promotes the formation of a protective barrier. However, it has been suggested that a relatively high Si concentration tends to have a negative effect on the oxidation resistance of Fe-15Cr steel.[13] Safikhani et al.[14] put forward that Ni can increase the resistance to spalling and an appropriate Mo content can improve the oxidation resistance. Cheng et al.[15] found that Mn affects the composition of the oxide scale and changes the breakaway oxidation process. These studies suggest that alloying elements can promote the oxidation resistance of low-Cr steels. Nevertheless, the effects of such alloying elements on the oxidation process of low-Cr steels remain unclear because the effects greatly vary depending on the Cr content in the steel matrix.[16] In this study, we experimentally and theoretically investigated the initial oxidation behavior of 5 wt pct Cr (5Cr) ferritic steel with addition of appropriate alloying elements. The effects of the alloying elements on th
Data Loading...
