PRODUCTION METHOD FOR HOT-DIP GALVANIZED STEEL SHEET

Title:

PRODUCTION METHOD FOR HOT-DIP GALVANIZED STEEL SHEET

Document Type and Number:

WIPO Patent Application WO/2014/091702

Kind Code:

A1

Abstract:

Provided is a method for producing a hot-dip galvanized steel sheet, using a high Si-containing steel sheet as the starting material therefor, that provides a beautiful external appearance with no surface defects, and has a high product yield. The production method for a hot-dip galvanized steel sheet hot-dip galvanizes and provides an excellent external appearance and excellent plating adhesion. When hot-dip galvanizing a steel sheet having a component composition including, in mass%, 0.05%-0.25% C, 0.1%-3.0% Si, 0.5%-3.0% Mn, 0.001%-0.10% P, 0.01%-3.00% Al, and no more than 0.200% S, the remainder thereof comprising Fe and unavoidable impurities, the production method: controls the furnace temperature (T) in a heating zone for an annealing furnace, on the basis of the water vapor partial pressure (PH20 in Air) in air introduced to the heating zone and performs heat treatment such that the steel sheet surface temperature reached is in the range of 600°-790°C; heats the steel sheet at a soaking temperature of 630°-850°C, in an atmosphere including hydrogen gas and water vapor gas having a hydrogen partial pressure (PH2) and a water vapor partial pressure (PH20) of 1,000 Pa≤PH2≤50,000 Pa and PH20≤610 Pa, the remainder thereof being N2 and unavoidable impurities; and hot-dip galvanizes.

Inventors:

TANAKA MINORU (JP)
SUZUKI YOSHITSUGU (JP)
MIYATA MAI (JP)
NAGATAKI YASUNOBU (JP)

Application Number:

PCT/JP2013/007015

Publication Date:

June 19, 2014

Filing Date:

November 29, 2013

Export Citation:

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Assignee:

JFE STEEL CORP (JP)

International Classes:

C21D9/46; C23C2/06; C22C18/04; C22C38/00; C22C38/60; C23C2/02; C23C2/28

Foreign References:

JP2004315960A	2004-11-11
JP2007231373A	2007-09-13
JP2011117069A	2011-06-16
JPH04202630A	1992-07-23
JPH06306561A	1994-11-01
JP2007291498A	2007-11-08

Other References: