桥梁缆索用超高强度钢丝的研究现状及发展趋势

Research Status and Development Tendency of Ultra-High Strength Steel Wire for Bridge Cables

随着桥梁建设向跨海、跨江、跨越大湾区以及跨越高山峡谷的方向发展,悬索桥和斜拉桥的跨度越来越大,对桥梁缆索用钢丝的要求也越来越高。桥梁缆索用钢丝的微观结构具有双层复合结构,由渗碳体片层和铁素体片层相互间隔组成,渗碳体片层决定其强度,铁素体片层决定其塑韧性,二者层间距的大小对其强韧性配比尤为重要。首先论述了国内外桥梁建设的发展以及桥梁缆索用超高强度钢丝的国内外生产与研究现状;然后讨论了桥梁缆索用超高强度钢丝的微观组织与宏观力学性能之间的关系,分析了其强韧化机理以及国内外热处理技术的优缺点。盘条的原始抗拉强度和冷拉拔加工过程中的形变量共同决定了冷拉拔钢丝的最终抗拉强度,在冷拉拔过程中组织形貌变化和累计的形变能是造成热镀锌过程中钢丝扭转性能降低的关键因素。桥梁缆索用超高强度钢丝存在的不足主要是缺乏与更高强度盘条相匹配的成分设计和热处理技术,及缺乏防止钢丝在热镀锌过程中扭转性能降低的先进冷拉拔加工技术。

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 plasticity-toughness 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 hot-dip 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.