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Patent Searching and Data


Title:
METHOD FOR MANUFACTURING HOT-DIP GALVANIZED STEEL SHEET
Document Type and Number:
WIPO Patent Application WO/2018/207560
Kind Code:
A1
Abstract:
Provided is a method for manufacturing a hot-dip galvanized steel sheet, with which it is possible to achieve a good plated external appearance with high plating adhesion without a deterioration in the tensile strength, even when subjecting a steel sheet having a Si-content of 0.2% by mass or greater to hot-dip galvanization. On the interior of an annealing furnace, a steel sheet is conveyed through a heating area, a soaking area, and a cooling area in this order, thereby annealing the steel sheet, and the steel sheet ejected from the cooling area is subjected to hot-dip galvanization. A reducing or non-oxidizing humidifying gas and a reducing or non-oxidizing drying gas are supplied to the soaking area. The CO-gas concentration is measured by providing a CO-gas concentration meter at a discharging section for the gases in the soaking area, the thickness of a decarburized layer on the steel sheet is calculated from the measured CO concentration, and at least one of the flow volume and dew point of the humidifying gas is controlled so that the calculated thickness of the decarburized layer becomes equal to or less than a pre-set thickness.

Inventors:
TAKEDA GENTARO (JP)
MAKIMIZU YOICHI (JP)
IKEDA GOSUKE (JP)
TAKAHASHI HIDEYUKI (JP)
Application Number:
JP2018/015737
Publication Date:
November 15, 2018
Filing Date:
April 16, 2018
Export Citation:
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Assignee:
JFE STEEL CORP (〒1000011, JP)
International Classes:
C23C2/02; C21D9/56; C22C38/00; C22C38/04; C23C2/06; C23C2/40
Domestic Patent References:
WO2017072989A12017-05-04
WO2007043273A12007-04-19
Foreign References:
JP2015054990A2015-03-23
JP2010202959A2010-09-16
JPH0860254A1996-03-05
JP2016117921A2016-06-30
Other References:
See also references of EP 3623492A4
Attorney, Agent or Firm:
SUGIMURA Kenji (〒1000013, JP)
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