(19)

(11)

EP 2 084 302 A1

(12)

(43) Date of publication: 05.08.2009 Bulletin 2009/32 (21) Application number: 07863864.0 (22) Date of filing: 02.11.2007

(51) International Patent Classification (IPC):  C21D 9/00(2006.01) (86) International application number: PCT/US2007/083530 (87) International publication number: WO 2008/058032 (15.05.2008 Gazette 2008/20)

(84) Designated Contracting States: AT BE BG CH CY CZ DE DK EE ES FI FR GB GR HU IE IS IT LI LT LU LV MC MT NL PL PT RO SE SI SK TR (30) Priority: 02.11.2006 US 555984 23.01.2007 US 626148 (71) Applicant: Hydril USA Manufacturing LLC Houston, TX 77032 (US)	(72) Inventors: HUFF, Philip A. Spring, TX 77379 (US) PRUDEN, Keith Katy, TX 77450 (US) (74) Representative: Dossmann, Gérard  Bureau D.A. Casalonga & Josse Bayerstrasse 71/73 80335 München 80335 München (DE)