摘要:
Provided is a hot-dip Al-Zn-Mg-Si coated steel sheet having good corrosion resistance in flat parts and edge parts, and also having excellent worked part corrosion resistance. The hot-dip Al-Zn-Mg-Si coated steel sheet includes a base steel sheet and a hot-dip coating on a surface of the base steel sheet. The hot-dip coating includes an interfacial alloy layer present at an interface with the base steel sheet and a main layer present on the interfacial alloy layer, and contains from 25 mass% to 80 mass% of Al, from greater than 0.6 mass% to 15 mass% of Si, and from greater than 0.1 mass% to 25 mass% of Mg. The Mg content and Si content in the hot-dip coating satisfy formula (1): M Mg / M Si ˆ’ 0.6 > 1.7 where M Mg represents the Mg content (mass%) and M Si represents the Si content (mass%).
摘要:
A hot-dip Zn-Al alloy coated steel sheet exhibiting a beautiful coating appearance with metallic luster, in which no spangle or very fine spangles are formed, and having excellent blackening resistance and a method for manufacturing the hot-dip Zn-Al alloy coated steel sheet are provided. The hot-dip Zn-Al alloy coated steel sheet includes a hot-dip Zn-Al alloy coating layer containing 1.0 to 10 percent by mass of Al, 0.2 to 1.0 percent by mass of Mg, 0.005 to 0.1 percent by mass of Ni, and the balance being Zn and incidental impurities on at least one surface of a steel sheet. The manufacturing method includes the steps of dipping the steel sheet into a hot-dip Zn-Al alloy coating bath and pulling up and cooling the steel sheet, wherein the steel sheet pulled up from the coating bath is cooled to 250°C at a cooling rate of 1°C to 15°C/sec.
摘要:
Disclosed is a hot-dip Al-Zn alloy coated steel sheet having good corrosion resistance in flat parts as well as good workability and thereby has excellent corrosion resistance in worked parts. In the disclosure, the upper layer of the hot-dip coating has a composition containing Al in an amount of 20 mass% to 95 mass%, Si in an amount of 10 % or less of the Al content, at least one of Ca and Mg, the total content of Ca and Mg being 0.01 mass% to 10 mass%, and the balance including Zn and incidental impurities, and the mean Vickers hardness of the hot-dip coating is 50 Hv to 100 Hv.
摘要:
A surface treated steel plate having excellent corrosion resistance which comprises a steel sheet plated with a zinc-based metal or aluminum-based metal, a composite oxide coating film formed on the metal-plated steel, and an organic coating film formed on the composite oxide coating film, wherein the composite oxide coating film contains oxide particles and phosphoric acid and/or a phosphoric acid derivative, and the organic coating film has a film thickness of 1 to 5 νm.