Sha Sha, Yang Feng, He Jianzhong, Liu Zhi, Fu Tianle, Wang Bing, Chen Xiaoping, Jia Shujun, Liu Qingyou
Central Iron and Steel Research Institute Limited Company, Beijing 100081, China.
College of New Energy and Materials, China University of Petroleum (Beijing), Beijing 102200, China.
Materials (Basel). 2024 Sep 11;17(18):4467. doi: 10.3390/ma17184467.
Plain carbon steel is the most widely applied steel in current engineering construction. With the increased application property needs, the service life of plain carbon steel has been severely tested. As one of the most destructive failure modes, corrosion resistance of carbon steel has attracted wide attention. Rare earth La, as the microalloying element, was employed in plain carbon steel, Q355, to improve its corrosion resistance. As the content of La increased, the microstructure was refined. The fraction of pearlite decreased, while the content of acicular increased. Within the La addition of 230 ppm, the tensile strength and impact energy were jointly improved. Furthermore, the microalloying element of La modified the inclusion types and refined the inclusion size. The modified microstructure and inclusions by La co-improved the corrosion resistance. The formula of effective La content was proposed to estimate the effect of La on corrosion. As the effective content of La increased, the relative corrosion rate decreased. La promoted the protective rust layer to increase corrosion resistance.
普通碳钢是当前工程建设中应用最为广泛的钢材。随着对应用性能需求的增加，普通碳钢的使用寿命受到了严峻考验。作为最具破坏性的失效模式之一，碳钢的耐腐蚀性已引起广泛关注。稀土元素镧作为微合金化元素被应用于普通碳钢Q355中，以提高其耐腐蚀性。随着镧含量的增加，微观组织得到细化。珠光体比例降低，针状组织含量增加。在添加量为230 ppm以内时，抗拉强度和冲击能量共同提高。此外，镧微合金化元素改变了夹杂物类型并细化了夹杂物尺寸。镧对微观组织和夹杂物的改性共同提高了耐腐蚀性。提出了有效镧含量公式来评估镧对腐蚀的影响。随着镧有效含量的增加，相对腐蚀速率降低。镧促进了保护性锈层的形成以提高耐腐蚀性。
