Park Jin Sung, Kim Si On, Jeong Young Jae, Lee Soon Gi, Choi Jong Kyo, Kim Sung Jin
Department of Advanced Materials and Metallurgical Engineering, Sunchon National University, Jungang-ro, Suncheon 540-742, Korea.
POSCO Technical Research Laboratories, Gyungbuk, Pohang 790-704, Korea.
Materials (Basel). 2022 Feb 25;15(5):1746. doi: 10.3390/ma15051746.
To expand the industrial applicability of strong and ductile high Mn-Low Cr steel, a deeper understanding and mechanistic interpretation of long-term corrosion behavior under harsher environmental conditions are needed. From this perspective, the long-term corrosion behaviors of 24Mn3Cr steel under acidic aqueous conditions were examined through a comparison with conventional ferritic steels using the electrochemical measurements (linear polarization resistance and impedance), and immersion test followed by the metallographic observation of corrosion morphologies. In contrast to conventional ferritic steels, 24Mn3Cr steel, which had the lowest corrosion resistance at the early immersion stages (i.e., the highest corrosion current density () and lowest polarization resistance ()), showed a gradual increase in corrosion resistance with prolonged immersion. Owing to the slow formation kinetics of (Fe,Cr)-enriched oxide scale, a longer incubation time for ensuring a comparatively higher corrosion resistance is required. On the other hand, conventional ferritic steels had an oxide scale with less densification and a lower elemental enrichment level that did not provide an effective anti-corrosion function. From the results, this study can provide significant insight into the industrial applicability of the high Mn-low Cr steel by providing the mechanistic interpretation of corrosion behaviors in acidic aqueous environments.
为了扩大高强度高韧性高锰低铬钢的工业适用性，需要对其在更恶劣环境条件下的长期腐蚀行为有更深入的理解和机理阐释。从这个角度出发，通过与传统铁素体钢进行对比，利用电化学测量（线性极化电阻和阻抗）以及浸泡试验并随后对腐蚀形貌进行金相观察，研究了24Mn3Cr钢在酸性水溶液条件下的长期腐蚀行为。与传统铁素体钢不同，24Mn3Cr钢在浸泡初期耐蚀性最低（即腐蚀电流密度最高、极化电阻最低），但随着浸泡时间延长，其耐蚀性逐渐提高。由于富（铁、铬）氧化皮的形成动力学缓慢，需要更长的孕育时间以确保相对较高的耐蚀性。另一方面，传统铁素体钢的氧化皮致密化程度较低且元素富集水平较低，无法提供有效的防腐功能。基于这些结果，本研究通过对酸性水环境中腐蚀行为的机理阐释，能够为高锰低铬钢的工业适用性提供重要见解。
