High-strength Zn—Al coated steel wire for bridges with excellent corrosion resistance and fatigue properties and method for manufacturing the same

摘要

Disclosed is a high-strength Zn—Al coated steel wire for bridges with excellent corrosion resistance and fatigue properties, the Zn—Al coated steel wire includes: a steel wire; and a Zn—Al coating having a coating body layer and an Fe—Al alloy layer formed in an interface between a surface layer of the steel wire and the coating body layer, wherein a chemical composition of a core material of the steel wire includes, by mass %: C: 0.70% to 1.2%; Si: 0.01% to 2.5%; Mn: 0.01% to 0.9%; P: limited to 0.02% or less; S: limited to 0.02% or less; N: limited to 0.01% or less; and the balance including Fe and unavoidable impurities, wherein wire-drawn pearlite is most abundant microstructure among microstructures of the core material of the steel wire; wherein an average composition of the Zn—Al coating includes, by mass %, Al: 3.0 to 15.0%; and Fe: limited to 3.0% or less, and wherein the Fe—Al alloy layer has a thickness of 5 μm or less.

主权项

1. A high-strength Zn—Al coated steel wire for bridges comprising:
a steel wire; and a Zn—Al coating having a coating body layer and an Fe—Al alloy layer formed in an interface between a surface layer of the steel wire and the coating body layer, wherein a chemical composition of a core material of the steel wire consists of, by mass %: C: 0.70% to 1.2%; Si: 0.01% to 2.5%; Mn: 0.01% to 0.9%; P: limited to 0.02% or less; S: limited to 0.02% or less; N: limited to 0.01% or less; and a balance including Fe and unavoidable impurities, wherein wire-drawn pearlite is the most abundant microstructure among microstructures of the core material of the steel wire; wherein an average composition of the Zn—Al coating consists of, by mass %: Al: 3.0 to 15.0%; Si: 0.2% to 1.5%; Fe: limited to 3.0% or less, and a balance including Zn and unavoidable impurities, wherein the Fe—Al alloy layer has a thickness of 5 μm or less and comprises an outer layer and an inner layer, wherein an Al3.2Fe columnar grain is the most abundant microstructure among microstructures in the outer layer, wherein Al5Fe2 columnar grain is the most abundant microstructure among microstructures in the inner layer, wherein the outer layer is located closer to the coating body layer than the inner layer, and the inner layer is located closer to the surface layer of the steel wire than the outer layer, wherein the Zn—Al coating further comprises an Fe—Al—Si granular grain layer between the outer layer of the Fe—Al alloy layer and the coating body layer.