集装箱用高强度耐候钢的开发及研究现状

Development and Research Status of High Strength Weathering Steel for Container

耐候钢在自然环境中与空气、雨水等发生反应,表面会形成稳定而致密的保护性锈层,相对于普碳钢,其具有较高的耐腐蚀性,因此,被大量应用于石油钻井、集装箱、铁道车辆等使用环境恶劣、对耐腐蚀性能有一定要求的结构中。近年来,在中欧班列、中亚班列等线路的快速发展以及“一带一路”倡议和高速治超等国家政策的支持导向下,铁路集装箱运输行业得到迅速发展,集装箱的轻量化、减薄化是其未来主要的发展方向。作为铁路集装箱主要材料的耐候钢,尤其是屈服强度为700 MPa级的高强耐候钢,由于其具有高的强度,可以大幅减轻集装箱的质量,实现集装箱的减薄,将得到大量应用。国外耐候钢开发起步较早,已经大规模推广应用,而我国的耐候钢虽然已经有所应用,但应用进展缓慢,仍需要开展高强度、高耐腐蚀性耐候钢的研发工作,以满足铁路集装箱的应用需求。目前,国内外学者对耐候钢的研究主要集中于不同成分体系下的耐腐蚀机理以及强韧化机理。本文从耐候钢的耐腐蚀机理、强韧化机理以及焊接性能方面进行了综述,主要针对钢的强韧性、焊接性以及耐候性等方面进行考虑,结合国内外耐候钢研究开发的经验,提出了高强度耐候钢化学成分设计思路和变形制度、温度制度和冷却制度的控制建议,确定了700 MPa以下级别高强耐候钢显微组织主要为铁素体+珠光体或粒状贝氏体;而700 MPa级别高强耐候钢显微组织控制目标则为细小的针状铁素体或粒状贝氏体。通过固溶强化、细晶强化、析出强化以及相变强化等多种手段满足性能要求,为今后集装箱用高强度耐候钢的研究和设计提供参考及依据。

Weathering steel reacted with air and rainwater in natural environment,and then an anticorrosion protective layer was formed on its surface.Thus the weathering steel had higher corrosion resistance than ordinary carbon steel.Therefore,it has been widely used on oil drilling,containers,railway vehicles and other structures with adverse and corrosive working condition.In recent years,with the China-Europe train,China-Asian train and other lines rapidly developing,and the support of state policies such as One belt,One road strategy and Expressway Entrance Control,railway container transport has been expanding in China.Light weight and thinning of container will be the main development direction in the future.As a railway container material,weathering steel,especially high strength weathering steel with yield strength of 700 MPa,can reduce the weight of container and realize the thinning of container,so it will be widely used.The development of weathering steel in foreign countries started earlier and had been widely applied.Although the weathering steel in China has been applied in some places,the application progress is still slow.It is necessary to carry out the research and development of weathering steel with high strength and high corrosion resistance to meet the application requirements of railway containers.At present,domestic and foreign scholars have mainly focused on the corrosion resistance and strengthening and toughening mechanism of weathering steel with different chemical compositions.In this paper,the corrosion resistance mechanism,the mechanism of strength and plasticity and the weldability of weathering steel were reviewed.Considering the strength,toughness,weldability,weather resistance of steel and the research and development experiences of weathering steel,the chemical composition design and the control strategies of deformation,temperature and cooling schedules of ultra-high strength weathering steel were put forward.It was determined that the microstructure of high strength weathering steel below 700 MPa was mainly ferrite+pearlite or granular bainite,while the microstructure of 700 MPa grade high strength weathering steel was fine acicular ferrite or granular bainite.The performance requirements can be met by combining multiple strengthening mechanism such as solution strengthening,fine grain strengthening,precipitation strengthening and phase transformation strengthening.The paper provided refe-rence and basis for the research and design of high strength weathering steel for containers in the future.