稀土在汽车用先进高强钢中的研究现状

Research status of rare earth in advanced high strength steel for automobile

成分设计与优化是先进高强钢增强、增塑以及增韧的关键技术之一。随着钢质高纯化装备和技术的进步与发展,稀土元素在钢中的应用已由净化、夹杂物改性逐步向微合金化过渡。从第一代铁素体基软钢和高强低合金钢向第二代奥氏体基超高强钢,再到多相、亚稳和多尺度组织调控的第三代高强韧性钢,先进高强钢的微合金化技术一直是控制组织和性能的有效举措。稀土原子具备较大原子半径以及与O、S的高亲和力等优异特性,可从控制凝固与固态相变,影响碳元素与合金元素的扩散等多方面影响先进高强钢的组织结构,从而对其力学性能、成形性能以及耐腐蚀等服役性能产生显著影响。本文阐述了稀土元素分别在第一代、第二代和第三代典型先进高强钢中的作用机理,并展望了稀土元素在未来汽车钢中的应用前景。

Composition design and optimization is one of the key technologies for strengthening,plasticizing and toughening advanced high-strength steel.With the progress and development of high-purity steel equipment and technology,the application of rare earth elements in steel has gradually changed from purification and inclusion modification to micro-alloying.From the first generation ferrite-based mild steel and high-strength low-alloy steel to the second generation austenite-based ultra-high-strength steel,and then to the third generation high-strength and toughness steel with multiphase,metastable and multi-scale microstructure control,the microalloying technology of advanced high-strength steel has always been an effective measure to control the microstructure and properties.Rare earth atoms have great atomic radius and high affinity with O and S,which can influence the microstructure of advanced high-strength steel in many aspects,such as controlling solidification and solid phase transformation,affecting the diffusion of carbon and alloy elements,and thus have a significant impact on its mechanical properties,formability and corrosion resistance.In this paper,the action mechanism of rare earth elements in the first,second and third generation typical advanced high-strength steels is described,and the application prospect of rare earth elements in future automobile steels is prospected.