HOT COIL FOR LINE PIPE AND MANUFACTURING METHOD THEREFOR

Title:

HOT COIL FOR LINE PIPE AND MANUFACTURING METHOD THEREFOR

Document Type and Number:

WIPO Patent Application WO/2013/047702

Kind Code:

A1

Abstract:

The present invention provides a hot coil for a line pipe with which variation in the room temperature strength is reduced and low-temperature toughness is improved even with a hot coil for which there are many restrictions on the manufacturing conditions in the winding process, and provides a method for manufacturing said hot coil. A steel plate is held for a prescribed time between each rolling pass in the recrystallization temperature range, and a two-stage cooling is performed after hot rolling, thereby providing the steel structure of the center of the plate thickness with an effective crystal grain diameter of 3-10 μm and a total area ratio of bainite and acicular ferrite of 60-99% and, when the total area ratio of bainite and acicular ferrite for two given locations respectively are A and B, with the absolute value of A-B being 0-30%.

Inventors:

HARA TAKUYA (JP)
KINOSHITA TAKESHI (JP)
TANAKA KAZUAKI (JP)

Application Number:

PCT/JP2012/074969

Publication Date:

April 04, 2013

Filing Date:

September 27, 2012

Export Citation:

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Assignee:

NIPPON STEEL & SUMITOMO METAL CORP (JP)

International Classes:

C22C38/14; C21D8/02; C21D9/46; C22C38/58

Domestic Patent References:

WO2010052926A1

2010-05-14

Foreign References:

JP2010196160A	2010-09-09
JP2007138290A	2007-06-07
JP2010196165A	2010-09-09
JP2010196156A	2010-09-09
JP2010174342A	2010-08-12
JP2010174343A	2010-08-12
JP2010196155A	2010-09-09
JP2010196156A	2010-09-09
JP2010196157A	2010-09-09
JP2010196160A	2010-09-09
JP2010196161A	2010-09-09
JP2010196163A	2010-09-09
JP2010196164A	2010-09-09
JP2010196165A	2010-09-09
JP2011195883A	2011-10-06
JP2008248384A	2008-10-16
JP2008163456A	2008-07-17

Other References: