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Manufacturing Technology of coiled tubing
- May 16, 2018 -

Coiled tubing is a new type of oil pipe with a single root length of thousands of meters and can be repeatedly bent and realized multiple plastic deformation. Coiled tubing and its operating equipment are known as "universal Machine", in foreign countries such as the United States, Canada, the coiled tubing has become an essential oil equipment in oil field operations. At present, the longest coiled tubing is 9000m long, the core technology of this special tubing manufacturing is: 1, chemical elements because of harsh service environment, the continuous tubing material mechanical properties and corrosion resistance of higher requirements, to the chemical composition of the material optimization design, but also to smelting, rolling, etc. to realize the whole process of clean control, 

 1,Minimize the contents of inclusions and S, p and other harmful elements. 

 2, processing due to dislocation proliferation and other causes of the processing hardening and bauschinger effect of the joint action, the strength of the transformation of the law of the Tube control. 

 3, Heat treatment through the tube body heat treatment, achieve the best structure and performance control, especially high-strength and high plasticity and low residual stress. 

 4, Welding technology for low carbon microalloyed steel, the main use of HFW welding technology, it is necessary to study the best welding parameters (such as current, voltage, frequency, welding speed, forming angle, extrusion, etc.), research weld and weld heat treatment technology. 5, plate Butt to achieve HFW welded pipe continuous production, the plate must first be connected to a long, the current plate butt mainly using TIG, mag and plasma welding methods. 

  The method being studied is friction stir welding. 6, Pipe butt coiled tubing in the use of the process may cause local damage, must be damaged or defective part of the removal, and through the welding pipe connection. 

  The traditional Butt-welding method is usually hand-tig welded, the welding quality is difficult to control, so the automatic welding technology is now made. 7, new manufacturing technology such as CVR technology, that is, the use of the same specifications of the Tube billet, on-line through the medium-frequency induction heating to 940 ℃, through the thermal mechanical rolling, on the one hand to achieve HFW weld optimization or seamless, on the other hand to achieve the wall thickness or change diameter. In addition, there are special stainless steel continuous tube laser welding technology.