Cangzhou Steel Pipe Group (CSPG) Co., Ltd.

Double Submerged Arc Welded Steel Pipe

Manufacturing technology of big straight seam submerged arc welding steel pipe.

The pipe is mainly used for the pipeline transportation of Marine and land oil and gas, oil and natural gas, coal and mining materials, etc. It is especially suitable for the "west-east gas transmission" project under construction in China, and can also be used for export and alternative import.

Germany SMSMEER, Japan NKK, Japan O.T.K (Osaka special steel pipe factory), India WELSPVN pipe making company, Korea hyundai heavy industry and shiya company, all have their unique pipe making technology, are the elite of international pipe making industry.

International pipe production technology and characteristics, the foreign production of large straight seam submerged arc welding pipe forming methods: UOE method, CFE roll forming method, RBE roll bending method, JCOE forming method, C forming method, PFP progressive bending forming method. A brief introduction is as follows:

The UOE method first presses the steel plates with pre-bending edges into u-shape in the forming die of the u-press, and then presses them into o-shape in the forming die of the o-press and welds them into tubes before overall diameter enlargement.
The UOE process is one of the most advanced processes in the world today. There are now nearly 30 such welded tube forming units worldwide.  The roll forming machine of CFE method is composed of preforming frame, flat roll frame, edge bending roll and small row roll frame. Due to the setting of many identical small row rolls, the track of steel plate edge in the forming process is almost straight, avoiding the phenomenon of "edge stretching". The quality of CFE forming is good, and the product quality is no different from UOF forming. This method is different from other forming methods in that the raw material is hot rolled strip steel coil. It is mainly suitable for the production of large quantities and single varieties of steel tubes, but it is difficult to produce high strength thick wall steel tubes and large diameter steel tubes.  The RBE roll bending method, which involves rolling steel plates between three or four rollers for many times, produces welded tubes that are close to UOE welded tubes in performance and reliability. In recent years, RBE method has been applied in some developing countries due to its low investment, fast plant construction, moderate output, great flexibility and strong adaptability to the market. However, due to the lack of support in the middle part of the upper roll formed by this forming method, the diameter of the formed steel tube cannot be less than 508mm (20in) due to its stiffness, which reduces the market share. The diameter of many pipes in China is below 508mm.  JCOE forming method: firstly, press the steel plate into a J shape on the hydraulic press; then press the edges on both sides; then press the steel plate into a C shape after several times of stamping; finally, press the steel plate into an O shape through the semi-o mold. The JCOE method is similar in quality to the UOE welded pipe, and the line price is much lower than the UOE unit, but its production efficiency is low. The C forming method USES two C forming machines instead of the U and O presses in the UOE unit. The forming process is as follows: the steel plates with preformed edges are formed first on one half of the steel plates on the first press, and then on the other half of the steel plates on the other press to form the o-tubes. The size of welded pipe produced by C forming method is suitable, the output is moderate, and the price of production line is low.  PFP progressive bending forming method is to bend the steel plate pre-bent at the end on the pressure machine with smaller step length and more times, and finally to form the round pipe through the joint welding machine. The PFP method can produce welded pipes of different diameters and wall thicknesses with a diameter less than 406mm. The welded pipes produced by this method are of good quality and moderate output.

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