The large-diameter straight section immersed curved steel pipe is mainly responsible for the pipeline transportation of marine and onshore oil and gas, oil and gas, coal and mineral pulp, and other culture media. They are particularly suitable for the "Western natural gas transmission" projects currently under construction in China and can also be used as import and export substitutes.
International pipeline manufacturing technology methods and characteristics. The formation methods for large-diameter curved steel pipes in foreign countries include UOE method, CFE roller formation method, RBE rolling bending formation method, JCOE formation method, C formation method, and PFP gradual bending. Formation methods, etc. A brief introduction is as follows:
1. The UOE method first presses the front steel plate into a U-shaped mold formed by a U-press, then presses it into an O-shaped shape, and then welds it into the pipeline to expand the overall diameter. The UOE method is an international advanced formation method. So far, there are nearly 30 sets of welded pipe units formed in the world. The UOE method is known for its high production efficiency and good product quality, but it is not expensive and has a large investment scale.
The roller forming machine of the CFE method consists of a performance frame, a flat roller frame, edge bending rollers, and a row of rollers. Due to the installation of many identical small rows of rollers, the trajectory of the steel plate edges during the forming process is almost straight, avoiding the phenomenon of "edge stretching". The CFE method has good formation quality, and its product quality is no different from the UOF method. This method uses hot rolled steel rings as raw materials, which is different from other formation methods. It is mainly suitable for producing large quantities and individual steel pipes, but it is difficult to produce high-strength thick walled steel pipes and large-diameter steel pipes.
3. The RBE rolling bending method involves rolling the steel plate multiple times between three to four rollers. In terms of performance and reliability, the welded pipes produced by this method are close to UOE welded pipes. The RBE method has low investment, factory construction, moderate output, greater flexibility, and strong market adaptability. In recent years, this method has been applied in some developing countries. However, due to the lack of support in the middle of the upper roller and the limitation of its stiffness, the diameter of the formed steel pipe cannot be less than 508mm (20 inches), thereby reducing market share. Many pipelines in our country have a diameter below 508mm.
4. JCOE formation method, first press the steel plate into the J-shaped hydraulic pressure. After pressing the edges on both sides, they are formed into a C-shape through various stamping processes. Finally, press it into an O shape using a semi O-shaped upper mold. The product quality of the JCOE method is close to that of UOE welded pipes, and the price of the operating line is much lower than that of UOE units, but its production efficiency is relatively low.
5. The C molding method uses two C molding machines to replace the U pressing in the UOE unit. The formation process is: the steel plate before bending first forms half of the steel plate on one press machine, and then forms on another press machine. The other half of the steel plate is formed on the machine to obtain an O-shaped circular tube. The welded pipes produced by the C-forming method have suitable dimensions, moderate output, and low production line prices.
6. The PFP progressive bending method involves gradually bending steel plates with smaller steps and more times, and forming circular pipes through a steel pipe seam welding machine. The PFP method always comes with a small amount of pressure, so the news tonnage is not large and the investment is also very small. This method can form welded pipes with different pipe diameters and wall thicknesses. The processed diameter may be less than 406mm, and the quality of the produced welded pipes is relatively high, good, and with a moderate yield.
