Hot-dip Zn—Al—Mg—Si—Cr alloy-coated steel material with excellent corrosion resistance
AssigneeNippon Steel & Sumitomo Metal Corporation
InventorsNobuyuki Shimoda, Yasuhide Morimoto
Life of this patent
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Abstract
The present invention provides a Zn—Al—Mg—Cr alloy-coated steel material with excellent corrosion resistance. A molten Zn—Al—Mg—Si—Cr alloy-coated steel material which is a steel material having a Zn—Al—Mg—Cr alloy coating layer and which has an interfacial alloy layer formed of coating layer components and Fe at the coating layer-steel material interface, wherein the interfacial alloy layer has a multilayer structure consisting of an Al—Fe-based alloy layer and an Al—Fe—Si-based alloy layer and furthermore, the Al—Fe—Si-based alloy layer contains Cr.
Claims15
A hot-dip Zn—Al—Mg—Si—Cr alloy-coated steel material having a coating layer on the surface of a steel material and having an interfacial alloy layer at the interface between said steel material and said coating layer,
- wherein the average composition of the entire coating layer consisting of said coating layer and said interfacial alloy layer contains, in mass %, Al:
- from 25 to 75%, Mg:
- from 0.1 to 10%, Si:
- more than 1% and 7.5% or less, and Cr:
- from 0.05 to 5.0%, with the balance being Zn and unavoidable impurities,
- wherein said interfacial alloy layer is composed of coating layer components and Fe and has a thickness of 0.05 to 10 μm or a thickness of 50% or less of the entire coating layer thickness,
- wherein said interfacial alloy layer has a multilayer structure consisting of an Al—Fe-based alloy layer and an Al—Fe—Si-based alloy layer,
- wherein said Al—Fe-based alloy layer contains Al, Fe, less than 2 mass % of Si and 0 mass % of Cr,
- wherein said Al—Fe—Si-based alloy layer contains Al, Fe, 2 mass % or more of Si and Cr, and
- wherein said Al—Fe—Si-based alloy layer consists of a layer containing Al, Fe, 2 mass % or more of Si and Cr and a layer containing Al, Fe, 2 mass % or more of Si and 0 mass % of Cr, and wherein the layer containing Al, Fe, 2 mass % or more of Si and Cr is in contact with the coating layer.
A hot-dip Zn—Al—Mg—Si—Cr alloy-coated steel material having a coating layer on the surface of a steel material and having an interfacial alloy layer at the interface between said steel material and said coating layer, wherein the average composition of the entire coating layer consisting of said coating layer and said interfacial alloy layer contains, in mass %, Al:
- from 25 to 75%, Mg:
- from 0.1 to 10%, Si:
- more than 1% and 7.5% or less, and Cr:
- from 0.05 to 5.0%, with the balance being Zn and unavoidable impurities, said interfacial alloy layer is composed of coating layer components and Fe and has a thickness of 0.05 to 10 μm or a thickness of 50% or less of the entire coating layer thickness, said interfacial alloy layer has a multilayer structure consisting of an Al—Fe-based alloy layer and an Al—Fe—Si-based alloy layer, and said Al—Fe—Si-based alloy layer contains Cr, wherein said Al—Fe-based alloy layer forms a columnar crystal and said Al—Fe—Si-based alloy layer forms a granular crystal.
A hot-dip Zn—Al—Mg—Si—Cr alloy-coated steel material having a coating layer on the surface of a steel material and having an interfacial alloy layer at the interface between said steel material and said coating layer, wherein the average composition of the entire coating layer consisting of said coating layer and said interfacial alloy layer contains, in mass %, Al:
- from 25 to 75%, Mg:
- from 0.1 to 10%, Si:
- more than 1% and 7.5% or less, and Cr:
- from 0.05 to 5.0%, with the balance being Zn and unavoidable impurities, said interfacial alloy layer is composed of coating layer components and Fe and has a thickness of 0.05 to 10 pm or a thickness of 50% or less of the entire coating layer thickness, said interfacial alloy layer has a multilayer structure consisting of an Al—Fe-based alloy layer and an Al—Fe—Si-based alloy layer, and said Al—Fe—Si-based alloy layer contains Cr, wherein said Al—Fe-based alloy layer consists of a layer composed of Al5Fe2 and a layer composed of Al3.2Fe.
Dependencies are inferred from the claim text.