Study On The Technology And Properties Of Zn-5Al-XRE And Zn-Cu-Ti Hot-dip Galvanized Coated Steel Wires For Bridge Cables

With the development of bridge engineering,the requirements of the mechanical properties and corrosion resistance of the steel wire used for bridge cable are increasing.The addition of appropriate amount of rare earth elements to Zn-5Al alloy can improve the coating structure and corrosion resistance.Zn-Cu-Ti alloy possesses excellent mechanical properties and corrosion resistance and the utilization of Zn-Cu-Ti alloy as hot-dip coating material for bridge cables was rarely reported.In this paper,steel wires coated by Zn-5Al-XRE and Zn-Cu-Ti alloy were investigated.The light microscope,scanning electron microscope,universal testing machine,winding test,X-ray diffraction,CuSO₄ test,neutral salt spray corrosion test,electrochemical workstation and other test equipment and methods were employed in this investigation.The effect of adding different content of rare earth elements on the microstructure and properties of Zn-5Al-XRE alloy coated steel wire was studied.In addition,the optimal hot-dip galvanized process of Zn-Cu-Ti alloy coating for high strength bridge cable was investigated.The conclusions were listed as follows:?1?The structure of the Zn-5Al-XRE alloy coating for steel wire was more compact and uniform than the Zn-5Al alloy coating.Also,the bonding between the Zn-5Al-XRE coating and the substrate was better.The Zn-5Al-XRE coated steel wire with the maximum tensile strength and the best corrosion resistance was produced when 0.08%rare earth element was added.?2?The surface quality of the Zn-Cu-Ti alloy coated steel wires produced with hot-dip galvanized time of 15s and 40s was poor with zinc neoplasms.Meanwhile,the surface peeling and cracking were observed in the winding test.The bonding of Zn-Cu-Ti alloy coating produced with hot-dip galvanized time of 15s was poor.The surface quality of the Zn-Cu-Ti alloy coated steel wire produced with hot-dip galvanized time of 20s to 35s was excellent.With the extension of the hot-dip galvanized time,the tensile strength of Zn-Cu-Ti alloy coated steel wire decreased slightly.With the hot-dip galvanized time of 30s,the corrosion resistance performance of Zn-Cu-Ti alloy coating reached the best.The tensile strength and corrosion resistance of the Zn-Cu-Ti alloy coated steel wire and the Zn-5Al alloy coated steel wire produced with hot-dip plating time of 30s were compared and Zn-Cu-Ti alloy coated steel wire showed the larger tensile strength and better corrosion resistance.