Aluminum-zinc-coated steel sheet (as amended)

Patent metadata

Field	Value
Publication number	US-2016047018-A1
Application number	US-201414779748-A
Country	US
Kind code	A1
Filing date	Mar 19, 2014
Priority date	Mar 25, 2013
Publication date	Feb 18, 2016
Grant date	—

Abstract

An Al—Zn-coated steel sheet that suppresses blistering and offers good corrosion resistance after painting is provided. The Al—Zn-coated steel sheet includes an Al—Zn coating layer on a steel sheet surface, the Al—Zn coating layer including two layers which are an interfacial alloy layer present in an interface with a base steel sheet and an upper layer disposed on the interfacial alloy layer. The upper layer contains compounds of Si and Ca or Si, Ca, and Al, and Ca/Si mass % ratio in the upper layer is 0.72 to 1.4. The interfacial alloy layer contains an Fe—Al compound and/or an Fe—Al—Si compound. In the upper layer, Si content is 0.1 to 2.0 mass % and Ca content is 0.001 to 2.0 mass %.

First claim

1 . An Al—Zn-coated steel sheet comprising:
an Al—Zn coating layer disposed on a steel sheet surface, the Al—Zn coating layer including two layers which are an interfacial alloy layer present in an interface with a base steel sheet and an upper layer disposed on the interfacial alloy layer,
wherein the upper layer contains compounds of Si and Ca or Si, Ca, and Al, and Ca/Si mass % ratio in the upper layer is 0.72 to 1.4,
the interfacial alloy layer contains an Fe—Al compound and/or an Fe—Al—Si compound, and
in the upper layer, Si content is 0.1 to 2.0 mass % and Ca content is 0.001 to 2.0 mass %.

2 . The Al—Zn-coated steel sheet according to claim 1 , wherein the upper layer contains 50 to 85 mass % Al, 11 to 49.8 mass % Zn, 0.1 to 2.0 mass % Si, 0.001 to 2.0 mass % Ca, and the balance being Fe and unavoidable impurities.

3 . The Al—Zn-coated steel sheet according to claim 1 , wherein the upper layer does not contain a Si phase composed of simple substance Si.

4 . The Al—Zn-coated steel sheet according to claim 1 , wherein Si in the upper layer forms an intermetallic compound with at least one element selected from Al, Ca, and Fe.

Assignees

• Jfe Steel Corp

Inventors

• Morimoto Minako
• Yoshida Masahiro
• Ando Satoru

Classifications

• C23C2/12

  Aluminium or alloys based thereon · CPC title

• C22C21/10 Primary

  with zinc as the next major constituent · CPC title

• C23C2/405

  Plates of specific length · CPC title

• B32B15/012

  one layer being formed of an iron alloy or steel, another layer being formed of aluminium or an aluminium alloy · CPC title

• C23C28/021

  including at least one metal alloy layer · CPC title