Classifications

• • F—MECHANICAL ENGINEERING; LIGHTING; HEATING; WEAPONS; BLASTING
  • F16—ENGINEERING ELEMENTS AND UNITS; GENERAL MEASURES FOR PRODUCING AND MAINTAINING EFFECTIVE FUNCTIONING OF MACHINES OR INSTALLATIONS; THERMAL INSULATION IN GENERAL
  • F16L—PIPES; JOINTS OR FITTINGS FOR PIPES; SUPPORTS FOR PIPES, CABLES OR PROTECTIVE TUBING; MEANS FOR THERMAL INSULATION IN GENERAL
  • F16L13/00—Non-disconnectable pipe joints, e.g. soldered, adhesive, or caulked joints
  • F16L13/02—Welded joints
• • E—FIXED CONSTRUCTIONS
  • E21—EARTH OR ROCK DRILLING; MINING
  • E21B—EARTH OR ROCK DRILLING; OBTAINING OIL, GAS, WATER, SOLUBLE OR MELTABLE MATERIALS OR A SLURRY OF MINERALS FROM WELLS
  • E21B17/00—Drilling rods or pipes; Flexible drill strings; Kellies; Drill collars; Sucker rods; Cables; Casings; Tubings

Definitions

• the present invention relates to a welded drill pipe in which the internal flash is removed, and to the relative procedure for its manufacturing.
• the external flash is easily removed with a cutting tool, whereas the elimination of the internal one is much more difficult.
• the inner flash disturbs the flow of the fluid inside the pipe and, due to its characteristic middle notch, can cause the crack initiations due to fatigue-stress in the welded joint.
• the invention and its relative manufacturing procedure solve the technical problem above mentioned as for it is characterized by the complete elimination of the flash, which fills a cavity produced in one of the two parts to be welded, for example, in the tool joint.
• all the fluid-dynamic troubles inside the pipe, caused by the inner flash are avoided as well as the crack initiations due to fatigue-stress in the welded joint.
• fig. 1 shows the modular portion of a friction welded drill pipe, manufactured according to the prior art
• • fig. 2 represents some shapes of the "flash", coming out from the friction welding process; • fig. 3 shows a first example of a friction welded joint with a cavity to be filled by the inner flash, according to the invention, placed between the pipe and male tool joint;
• fig. 4 shows a second example of a friction welded joint with a cavity to be filled by the inner flash, according to the invention, placed between the pipe and female tool joint.
• number 1 shows a modular portion of a drill pipe for civil engineering comprising a pipe 2, a male tool joint 3 and a female tool joint 4.
• Said portion 1 has been manufactured by means of friction welding between pipe and tool joints, both male and female.
• the friction welding is made by means of strong impact between the two parts to be welded; moreover, to improve the junction between them, the parts are heated to a forging temperature obtained by the rotation of one part with respect to the other.
• T e process produces a very compact and highly resistant joint and is characterized by a good repetitiveness of its phases and.
• a disadvantage of the process lies in the formation of the flash 5 ; it is a burr which comes out just during the heating phase (produced by the friction between the two parts to be welded) and takes a shape like those schematically shown in fig. 2. In particular, it is characterized by the presence of a double burr 6 which causes vortices into the fluid flow and by a middle notch 7, possible crack initiation due to fatigue-stress in the welded joint.
• the removal of the inner flash can be obtained, according to the invention, manufacturing one of the two parts to be friction welded (for example, the tool joint) as the one shown in fig. 3.
• the male tool joint 8 comprises an externally threaded portion 9, an internal shape 10, suitable to allow the proper motion of the fluid, a stop surface 11 , against which the section 20 to be welded is to be placed, a coupling surface 12 for said section and it is characterized by a cavity 13, whose volume and shape are such as to be completely filled with the inner flash produced by the welding process. Consequently the complete and perfect filling of the cavity avoids the formation of the middle notch.
• the same manufacturing, according to the invention, is depicted in fig. 4.
• the female tool joint 14 comprises an internally threaded portion 15, an internal shape 16, suitable to allow the proper motion of the fluid, a stop surface 17, against which the section 20 to be welded is to be placed, a coupling surface 18 for said section and it is characterized by a cavity 19 with the same characteristics of the cavity 13 realized in the male tool joint.

Landscapes

• Engineering & Computer Science (AREA)
• General Engineering & Computer Science (AREA)
• Mechanical Engineering (AREA)
• Mining & Mineral Resources (AREA)
• Life Sciences & Earth Sciences (AREA)
• Geology (AREA)
• Fluid Mechanics (AREA)
• Environmental & Geological Engineering (AREA)
• Physics & Mathematics (AREA)
• General Life Sciences & Earth Sciences (AREA)
• Geochemistry & Mineralogy (AREA)
• Pressure Welding/Diffusion-Bonding (AREA)
• Braking Arrangements (AREA)

Applications Claiming Priority (3)

Publications (1)

Family

ID=11335739

Family Applications (1)

Country Status (4)

Cited By (1)

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Family Cites Families (4)

• 1996
  • 1996-09-26 IT IT96BA000041A patent/IT1287029B1/it active IP Right Grant
• 1997
  • 1997-07-28 EP EP97931974A patent/EP0931202A1/de not_active Withdrawn
  • 1997-07-28 WO PCT/IB1997/000949 patent/WO1998013574A1/en not_active Ceased
  • 1997-07-28 AU AU35551/97A patent/AU3555197A/en not_active Abandoned

Non-Patent Citations (1)

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