(1. International Research Institute for Steel Technology, Wuhan University of Science and Technology, Wuhan 430081, China) (2. School of Mechanical Engineering, Jingchu University of Technology, Jingmen 448000, China) (3. Research Institute of Wuhan Iron & Steel Group, Wuhan 430080, China) (4. Jiangsu Huaneng Cable Co., Ltd., Gaoyou 225613, China)
With the development of bridge construction in the direction of sea-crossing, river-crossing, bay-crossing and mountain-crossing, the requirement of bridge cable steel wire is higher since the span of suspension bridges and cable-stayed bridges is getting larger. The double-layer composite microstructure of bridge cable steel wire is composed of cementite lamellae and ferrite lamellae with certain intervals. And, the strength and plasticitytoughness of bridge cable steels are depended on cementite lamellae and ferrite lamellae, respectively. The distance between two lamella is particularly important for the strength and toughness of bridge cable steels. Firstly, the production and research status of ultra-high strength steel wire（UHSSW) for bridge cables worldwide was reviewed in this paper, as well as the development of bridge construction. Moreover, the relationship between microstructure and mechanical properties of UHSSW for bridge cables was discussed. Its strengthening-toughening mechanism was analyzed. The advantages and disadvantages of heat treatment technology being applied on UHSSW for bridge cables were also analyzed. The final tensile strength of cold drawing steel wire is determined by both original tensile strength of wire rod and deformation during cold drawing process. The microstructure variation and accumulated deformation energy during cold drawing process are the key factors for reducing torsional property of steel wire in hotdip galvanizing process. Meanwhile, the shortcomings of UHSSW for bridge cables were pointed out. These are lack of composition design and heat treatment technology matching higher strength wire rod, and advanced cold drawing technology for preventing the torsional property degradation of steel wire during hot-dip galvanizing.