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Method for manufacturing steel sheet coated with zinc-based coating layer (as amended)

a coating layer and zinc-based technology, applied in the direction of coating, superimposed coating process, metallic material coating process, etc., can solve the problems of surface appearance irregularity and surface appearance related to surface appearance, and achieve the effect of reducing the amount, effective removal of oxides, and reducing the time required for forming a reaction layer

Inactive Publication Date: 2017-11-02
JFE STEEL CORP
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  • Summary
  • Abstract
  • Description
  • Claims
  • Application Information

AI Technical Summary

Benefits of technology

The present invention provides a method for manufacturing a steel sheet coated with a zinc-based coating layer that can effectively remove oxides on the surface through contact with an alkaline aqueous solution and decrease the amount of precipitates generated during the treatment process, resulting in a steel sheet with a good surface appearance and a reaction layer.

Problems solved by technology

However, in the case of ordinarily used continuous treatment equipment, since pressing flaws occur on the surface of a steel sheet due to precipitates of Zn and Al generated in the alkaline aqueous solution adhering to deflecting rolls and supporting rolls, there is a case where problems related to surface appearance such as an irregularity in surface appearance occurs after a reaction layer has been formed.

Method used

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  • Method for manufacturing steel sheet coated with zinc-based coating layer (as amended)

Examples

Experimental program
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Effect test

example 1

[0046]Hereafter, the present invention will be described on the bases of examples. The scope of the present invention is not limited to the examples described below.

[0047]A skin pass rolling was performed on steel sheets which had been prepared by performing a galvanizing treatment on cold-rolled steel sheets having a thickness of 0.7 mm and a width of 1100 mm. Subsequently, the steel sheets were subjected to a treatment for removing an oxide layer in which the steel sheets were kept in contact with the alkaline aqueous solutions prepared under the conditions given in Tables 1-1 and 1-2 over the specified times, then washed with water, and then dried.

[0048]Also, steel sheets which had been prepared by performing a galvanizing treatment followed by an alloying treatment and skin pass rolling on a cold-rolled steel sheets having a thickness of 0.7 mm and a width of 1100 mm and steel sheets which had been prepared by performing an electro-galvanizing treatment on cold-rolled steel shee...

example 2

[0068]Analysis was performed on the oxide layer containing a crystal-structured substance expressed by Zn4(SO4)1-X(CO3)X(OB)6.nH2O of Nos. 2 through 53, 55, and 57.

[0069](4) Confirmation of Zn4(SO4)1-X(CO3)X(OH)6.nH2O

[0070]By brushing the surface of the oxide layer containing a crystal-structured substance expressed by Zn4(SO4)1-X(CO3)X(OH)6.nH2O by using a stainless brush having bristles having a diameter of 0.15 mm and a length of 45 mm and ethanol, and by suction filtering of the obtained ethanol solution, the components of the film were taken in the form of powder. Quantitative analysis of C was performed by programmed temperature gas chromatography on the components of the film taken in the form of powder components by using a gas chromatography mass spectrometer. A pyrolytic furnace was connected to the front part of the gas chromatography mass spectrometer. By charging about 2 mg of the taken powder sample into the pyrolytic furnace, and by transporting a gas generated in the...

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Abstract

A steel sheet coated with a zinc-based coating layer having a reaction layer on the surface of the steel sheet is manufactured by a method that includes bringing a steel sheet coated with a zinc-based coating layer into contact for 1.0 second or more with an alkaline aqueous solution containing one or more chelating agents selected from among sodium gluconate, sodium glucoheptonate, sodium citrate, tartaric acid, arabonic acid, galactonic acid, sorbit, mannite, glycerin, EDTA, and sodium tripolyphosphate in a total amount of 0.050 mass % or more and having a pH of 10.0 or more as a pre-treatment before a formation of the reaction layer, and forming the reaction layer being an oxide layer containing a crystal-structured substance expressed by Zn4(SO4)1-X(CO3)X(OH)6.nH2O.

Description

CROSS REFERENCE TO RELATED APPLICATIONS[0001]This is the U.S. National Phase application of PCT / JP2015 / 005583, filed Nov. 9, 2015, and claims priority to Japanese Patent Application No. 2014-229484, filed Nov. 12, 2014, the disclosures of each of these applications being incorporated herein by reference in their entireties for all purposes.TECHNICAL FIELD OF THE INVENTION[0002]The present invention relates to a method for manufacturing a steel sheet coated with a zinc-based coating layer having a reaction layer.BACKGROUND OF THE INVENTION[0003]A steel sheet coated with a zinc-based coating layer has been used in a wide range of applications mainly in automobile bodies, domestic electrical appliances, and building materials. There is a known technique in which properties such as press formability, corrosion resistance, and surface appearance quality of a steel sheet coated with a zinc-based coating layer used in such applications are improved by forming a reaction layer on the surfac...

Claims

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Application Information

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Patent Type & Authority Applications(United States)
IPC IPC(8): C23C22/83C23C22/60
CPCC23C22/60C23C22/83C23C22/53C23C22/78C23G1/20C23C28/3225C23C28/34
Inventor HOSHINO, KATSUYATAIRA, SHOICHIROFURUYA, SHINICHI
Owner JFE STEEL CORP