Invention Grant
- Patent Title: Method for the production of hot-finished seamless pipes having optimized fatigue properties in the welded state
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Application No.: US12670230Application Date: 2008-06-26
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Publication No.: US09718116B2Publication Date: 2017-08-01
- Inventor: Markus Ring , Gerd Kloster , Oliver Sommerkamp , Caroline Rott , Marion Erdelen-Peppler
- Applicant: Markus Ring , Gerd Kloster , Oliver Sommerkamp , Caroline Rott , Marion Erdelen-Peppler
- Applicant Address: DE Düsseldorf
- Assignee: VALLOUREC DEUTSCHLAND GMBH
- Current Assignee: VALLOUREC DEUTSCHLAND GMBH
- Current Assignee Address: DE Düsseldorf
- Agency: Henry M. Feiereisen LLC
- Priority: DE102007034895 20070724
- International Application: PCT/DE2008/001064 WO 20080626
- International Announcement: WO2009/012744 WO 20090129
- Main IPC: B21J5/08
- IPC: B21J5/08 ; B21K21/12

Abstract:
The invention relates to a method for the production of hot-finished, particularly hot-rolled, seamless pipes having optimized fatigue properties in the welded state, having an outside diameter of up to 711 mm and a nominal wall thickness of up to 100 mm, made of metal, in particular steel. After hot or finish rolling, a defined pipe cross-section is produced on at least one pipe end across a predetermined length, having tight tolerances for inside and outside diameters, wherein the cross-section can then be welded to the pipe end of another pipe. According to the invention, in a region a wall thickness is created in a first step at the pipe end in question, the thickness being bigger than on the remaining pipe body, wherein the outside diameter is increased and/or the inside diameter is reduced. In a second step, the required pipe cross-section is produced in said region by mechanical treatment, and the transition from the treated to the untreated region of the pipe is produced with low surface roughness and almost notch-free, and the residual wall thickness remaining in the treatment region is within the required tolerances.
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