EP 3686305 A4 20210127 - STEEL PIPE AND STEEL PLATE
Title (en)
STEEL PIPE AND STEEL PLATE
Title (de)
STAHLROHR UND STAHLPLATTE
Title (fr)
TUBE EN ACIER ET PLAQUE D'ACIER
Publication
Application
Priority
JP 2017033706 W 20170919
Abstract (en)
[origin: EP3686305A1] A steel pipe includes: a base metal that includes a cylindrical steel plate having a predetermined chemical composition; and a weld that is provided in a seam portion of the steel plate and extends in a longitudinal direction of the steel plate, in which a surface layer microstructure that is a microstructure in a range up to 1.0 mm from a surface of the base metal in a depth direction includes polygonal ferrite and granular bainite, an area fraction of the polygonal ferrite in the surface layer microstructure is 0 to 70%, a total area fraction of the polygonal ferrite and the granular bainite in the surface layer microstructure is 50% or more, a maximum hardness in the surface layer microstructure is 270 Hv or lower, an area fraction of polygonal ferrite in an internal microstructure that is a microstructure in a range up to a thickness center from an area positioned at a distance of more than 1.0 mm from the surface of the base metal in the depth direction is 40% or less, a maximum hardness in the internal microstructure is 248 Hv or lower, and an average hardness in the internal microstructure is 150 to 220 Hv.
IPC 8 full level
C22C 38/00 (2006.01); C21D 1/19 (2006.01); C21D 8/02 (2006.01); C21D 8/10 (2006.01); C21D 9/08 (2006.01); C22C 38/02 (2006.01); C22C 38/04 (2006.01); C22C 38/06 (2006.01); C22C 38/08 (2006.01); C22C 38/12 (2006.01); C22C 38/14 (2006.01); C22C 38/16 (2006.01); C22C 38/18 (2006.01); C22C 38/22 (2006.01); C22C 38/24 (2006.01); C22C 38/26 (2006.01); C22C 38/28 (2006.01); C22C 38/40 (2006.01)
CPC (source: EP KR)
C21D 8/0205 (2013.01 - KR); C21D 8/105 (2013.01 - EP KR); C21D 9/085 (2013.01 - EP); C22C 38/001 (2013.01 - EP); C22C 38/002 (2013.01 - EP); C22C 38/005 (2013.01 - EP); C22C 38/02 (2013.01 - EP); C22C 38/04 (2013.01 - EP); C22C 38/06 (2013.01 - EP); C22C 38/08 (2013.01 - EP); C22C 38/12 (2013.01 - EP); C22C 38/14 (2013.01 - EP); C22C 38/16 (2013.01 - EP); C22C 38/18 (2013.01 - EP); C22C 38/22 (2013.01 - EP); C22C 38/24 (2013.01 - EP); C22C 38/26 (2013.01 - EP); C22C 38/28 (2013.01 - EP); C22C 38/40 (2013.01 - EP); C22C 38/58 (2013.01 - KR); C21D 1/19 (2013.01 - EP); C21D 8/0205 (2013.01 - EP); C21D 8/0263 (2013.01 - EP); C21D 2211/002 (2013.01 - EP); C21D 2211/005 (2013.01 - EP); C21D 2211/008 (2013.01 - EP)
Citation (search report)
[X] WO 2013114519 A1 20130808 - NIPPON STEEL & SUMITOMO METAL CORP [JP]
Designated contracting state (EPC)
AL AT BE BG CH CY CZ DE DK EE ES FI FR GB GR HR HU IE IS IT LI LT LU LV MC MK MT NL NO PL PT RO RS SE SI SK SM TR
DOCDB simple family (publication)
EP 3686305 A1 20200729; EP 3686305 A4 20210127; CN 111094608 A 20200501; CN 111094608 B 20211026; JP 6319539 B1 20180509; JP WO2019058420 A1 20191107; KR 102364255 B1 20220217; KR 20200039738 A 20200416; WO 2019058420 A1 20190328
DOCDB simple family (application)
EP 17926174 A 20170919; CN 201780094849 A 20170919; JP 2017033706 W 20170919; JP 2018502833 A 20170919; KR 20207006880 A 20170919