Large-diameter straight seam submerged arc steel pipes are mainly used for pipeline transportation of marine and land oil and gas, petroleum and natural gas, coal, ore slurry, etc. They are especially suitable for the “West-East Gas Transmission” project currently under construction in my country, and can also be used for export and import substitution.
International pipe manufacturing technology, process methods, and characteristics. The forming methods for producing large-diameter straight seam submerged arc welded steel pipes abroad include the UOE method, CFE roll forming method, RBE roll bending forming method, JCOE forming method, C forming method, PFP step-by-step bending forming method, etc. A brief introduction is as follows:
1. The UOE method first presses the pre-bent steel plate into a U shape in the forming die of the U press and then presses it into an O shape in the forming die of the O press. After welding into a pipe, the overall diameter is expanded. The UOE method is one of the most advanced forming methods in the world today. So far, there are nearly 30 such forming welded pipe units in the world. The UOE method is famous for its high production efficiency and good product quality, but it is expensive and has a large investment scale.
2. The CFE method’s roll-forming machine consists of a performing frame, a flat roll frame, an edge bending roll, and a small roll frame. Due to the setting of many identical small rolls, the trajectory of the steel plate edge during the forming process is almost straight, avoiding the “edge stretching” phenomenon. The CFE method has good forming quality, and its product quality is no different from that of the UOF method. This method uses hot roll strip steel coils as raw materials, which is different from other forming methods. It is mainly suitable for the production of large quantities and single varieties of steel pipes, but it is difficult to produce high-strength thick-walled steel pipes and large-diameter steel pipes.
3. The RBE roll forming method forms the steel plate through multiple rolling between three or four rolls. The welded pipes produced by this method are close to the UOE welded pipes in terms of performance and reliability. The RBE method requires little investment, fast plant construction, moderate output, high 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 of this forming method, the diameter of the formed steel pipe cannot be less than 508mm (20in), which reduces the market share. The diameter of many pipes in my country is below 508mm.
4. JCOE forming method: First, the steel plate is pressed into a J shape on a hydraulic press, and after the two sides are pressed, it is formed into a C shape through multiple stamping and finally pressed into an O shape through a semi-O-shaped upper mold. The product quality of the JCOE method is close to that of the UOE welded pipe, and the price of the operating line is much lower than that of the UOE unit, but its production efficiency is low.
5. C forming method: Two C forming machines are used to replace the U press and O press in the UOE unit. The forming process is as follows: the pre-bent steel plate is first formed into half of the steel plate on the first press, and then the other half of the steel plate is formed on the other press, thereby obtaining an O-shaped round tube. The welded pipe produced by the C forming method has a suitable size, moderate output, and a low production line price.
6. The PFP step-by-step bending forming method is to bend the steel plate with a pre-bent end on the press with a smaller step length and more times, and finally form it into a round pipe through a steel pipe joint welding machine. The PFP method has a small amount of pressing each time, so the press tonnage is not large, and the investment is also small. This method can form welded pipes of different diameters and wall thicknesses. The processed diameter can be less than 406mm. The quality of the welded pipe produced is good and the output is moderate.
Post time: Sep-26-2024