Chang Jiang, Hu Yuantao, Yang Yonggang, Jiang Chen, Liu Jianling, Zhang Borui, Yang Xiong, Mi Zhenli
National Engineering Research Center for Advanced Rolling and Intelligent Manufacturing, University of Science and Technology Beijing, Beijing 100083, China.
Sinosteel Anhui Tianyuan Technology Co., Ltd., Ma'anshan 243004, China.
Materials (Basel). 2025 Aug 12;18(16):3774. doi: 10.3390/ma18163774.
The oxidation behaviors of varying Cr-alloyed automotive beam steels-0.015 wt.% Cr, 0.15 wt.% Cr, and 1 wt.% Cr-were investigated using isothermal oxidation experiments. The morphologies of the oxide scale were characterized, and the formation mechanisms were analyzed to understand the change in the oxidation kinetics of the investigated steels. The results show that a small amount of Cr, up to 0.15 wt.%, can reduce oxidation kinetics; the addition of Cr at 1 wt.% causes the oxidation rate to decline at a low isothermal temperature, but the hindrance effect expires when the oxidation temperature is above 1050 °C. The oxidation scale, including the inner FeO layer, the intermediate FeO layer, and the outer FeO layer, exhibits a morphological evolution from marble-like to pore-like, then whisker-like, flocculation-like, fine oxide grains, and finally coarse oxide grains. With increasing Cr addition, the thickness of the FeO layer decreases significantly, leading to a reduction in the total thickness of the oxidation scale. During the oxidation process of the investigated steel with 0.15 wt.% Cr, a Cr-rich layer and FeO-(Cr, Fe, Mn)O eutectic form; meanwhile, FeO-(Cr, Fe)O eutectic and Si-rich oxides, as well as a (Cr, Si)-rich layer, occur in the oxidation scale when 1 wt.% Cr is added to the steel. The occurrence of voids in the (Cr, Si)-rich layer is responsible for the increasing oxidation kinetics of the 1 wt.% Cr steel when the isothermal temperature is above 1050 °C, and the optimal Cr concentration in automotive beam steel is 0.15 wt.%, considering both oxidation resistance and cost.
采用等温氧化实验研究了不同铬含量（0.015 wt.% Cr、0.15 wt.% Cr和1 wt.% Cr）的汽车大梁钢的氧化行为。对氧化皮的形貌进行了表征，并分析了其形成机制，以了解所研究钢种氧化动力学的变化。结果表明，少量的铬（高达0.15 wt.%）可以降低氧化动力学；添加1 wt.% 的铬会使在较低等温温度下氧化速率下降，但当氧化温度高于1050 °C时，这种阻碍作用消失。氧化皮包括内FeO层、中间FeO层和外FeO层，其形貌从大理石状演变为孔隙状，然后是晶须状、絮凝状、细小氧化物颗粒，最后是粗大氧化物颗粒。随着铬含量的增加，FeO层的厚度显著减小，导致氧化皮总厚度减小。在含0.15 wt.% Cr的研究钢的氧化过程中，形成了富铬层和FeO-(Cr, Fe, Mn)O共晶；同时，当钢中添加1 wt.% 的铬时，氧化皮中出现了FeO-(Cr, Fe)O共晶和富硅氧化物以及富(Cr, Si)层。当等温温度高于1050 °C时，富(Cr, Si)层中孔隙的出现导致含1 wt.% Cr钢的氧化动力学增加，综合考虑抗氧化性和成本，汽车大梁钢的最佳铬浓度为0.15 wt.%。
