EP 2562284 B1 20200603 - Cr-CONTAINING STEEL PIPE FOR LINE PIPE AND HAVING EXCELLENT INTERGRANULAR STRESS CORROSION CRACKING RESISTANCE AT WELDING-HEAT-AFFECTED PORTION
Title (en)
Cr-CONTAINING STEEL PIPE FOR LINE PIPE AND HAVING EXCELLENT INTERGRANULAR STRESS CORROSION CRACKING RESISTANCE AT WELDING-HEAT-AFFECTED PORTION
Title (de)
CR-HALTIGES STAHLROHR FÜR EIN LEITUNGSROHR MIT HERVORRAGENDER BRUCHFESTIGKEIT DER DURCH SCHWEISSUNGSHITZE BETROFFENEN TEILE BEI INTERGRANULARER STRESSKORROSION
Title (fr)
TUYAU D'ACIER CONTENANT DU CHROME POUR UNE CANALISATION AYANT UNE EXCELLENTE RÉSISTANCE À LA FISSURATION PAR CORROSION INTERGRANULAIRE SOUS CONTRAINTE DANS LA PARTIE AFFECTÉE PAR LA CHALEUR DE SOUDAGE
Publication
Application
Priority
- JP 2010095860 A 20100419
- JP 2011059891 W 20110415
Abstract (en)
[origin: EP2562284A1] Provided is a Cr-containing steel pipe for linepipe having X-65 to X-80 class high strength and being excellent in toughness, corrosion resistance and resistance to sulfide stress corrosion cracking, and also being excellent in resistance to intergranular stress corrosion cracking in a welded heat affected zone. To be more specific, the composition of the Cr-containing steel pipe contains, by mass% 0.001 to 0.015% C, 0.05 to 0.50% Si, 0.10 to 2.0% Mn, 0.001 to 0.10% Al, 15.0 to 18.0% Cr, 2.0 to 6.0% Ni, 1.5 to 3.5% Mo, 0.001 to 0.20% V, and 0.015% or less N so as to satisfy the following relationship of Cr + Mo + 0.4W + 0.3Si - 43.5C - 0.4Mn - Ni - 0.3Cu- 9N: 11.5 to 13.3. A welded heat affected zone which is heated to a ferrite single phase temperature region of 1300°C or more at the time of welding and is cooled has the microstructure where 50% or more of prior-ferrite grain boundaries is occupied by a martensite phase and/or an austenite phase in a ratio to the whole length of the prior-ferrite grain boundaries. Accordingly, the formation of a Cr carbide depleted zone is suppressed thus providing a steel pipe which remarkably enhances resistance to intergranular stress corrosion cracking in a welded heat affected zone. Due to such a steel pipe, it is possible to acquire an advantageous effect that it becomes unnecessary to perform post weld heat treatment thus remarkably shortenning a construction period of the welded steel pipe structure.
IPC 8 full level
C21D 1/25 (2006.01); C21D 6/00 (2006.01); C21D 9/08 (2006.01); C21D 9/50 (2006.01); C22C 38/00 (2006.01); C22C 38/02 (2006.01); C22C 38/04 (2006.01); C22C 38/06 (2006.01); C22C 38/44 (2006.01); C22C 38/46 (2006.01); C22C 38/58 (2006.01)
CPC (source: EP)
C21D 1/25 (2013.01); C21D 6/002 (2013.01); C21D 6/004 (2013.01); C21D 9/08 (2013.01); C21D 9/50 (2013.01); C22C 38/001 (2013.01); C22C 38/02 (2013.01); C22C 38/04 (2013.01); C22C 38/06 (2013.01); C22C 38/44 (2013.01); C22C 38/46 (2013.01); C21D 2211/001 (2013.01); C21D 2211/005 (2013.01); C21D 2211/008 (2013.01)
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 2562284 A1 20130227; EP 2562284 A4 20170712; EP 2562284 B1 20200603; BR 112012026595 A2 20160712; CN 102859019 A 20130102; JP 2011241477 A 20111201; JP 5765036 B2 20150819; WO 2011132765 A1 20111027
DOCDB simple family (application)
EP 11772096 A 20110415; BR 112012026595 A 20110415; CN 201180019574 A 20110415; JP 2011059891 W 20110415; JP 2011092571 A 20110419