Manufacturing Technology of Large Diameter LSAW Steel PipeMassive-diameter LSAW steel pipes are mostly accountable for the pipeline transportation of marine and terrestrial oil and fuel, oil and natural gas, coal and ore pulp, and so forth., specifically suitable for the "West-East Fuel Transmission" project presently under development in China, and can also be utilised for export and substitute imports . Germany SMSMEER (formerly well-known global Mannesmann) company, Japan NKK business, Japan OTK (Osaka Unique Steel Tube Plant), India WELSPVN pipe manufacturing company, South Korea Hyundai Heavy Industries and Seiya firm all have their very own exclusive pipe making technologies, They are all elites in the international management industry.
Procedure methods and traits of global pipe-producing technology. The forming methods for generating massive-diameter LSAW steel pipes abroad consist of: UOE forming strategy, CFE row roll forming strategy, RBE roll forming approach, JCOE forming method, C forming method, PFP gradual folding Bending forming strategy, and so on. A quick introduction is as follows:
1. UOE molding approach
First, the pre-bent steel plate is pressed into a U form in the forming die of the U press, and then pressed into an O shape in the forming die of the O press, and then welded into a tube and then the all round diameter is expanded. The UOE method is one of the most sophisticated forming techniques in the world nowadays. So far, there are nearly thirty sets of such forming welded pipe units in the world. The UOE strategy is known for its high production efficiency and very good solution high quality, but it is not high-priced and has a massive investment scale.
2. CFE molding strategy
The row roll forming machine is composed of a pre-forming stand, a flat roll stand, an edge bending roll and a little row roll stand. Due to the set up of a lot of small rows of the very same rolls, the trajectory of the edge of the steel plate throughout the forming method is almost straight. Steer clear of "edge stretch" phenomenon. CFE molding approach has great molding top quality, and its solution quality is no distinct from UOF molding technique. This method makes use of scorching rolled strip steel coils as raw supplies, which is different from other forming techniques. It is mostly suitable for the manufacturing of large-scale, single-variety steel pipes, but it is tough to produce large-power thick-wall steel pipes and large-diameter steel pipes.
three. RBE roll forming method
The steel plate is rolled into numerous times among 3 or 4 rolls. The welded pipe produced by this method is close to UOE welded pipe in terms of performance and dependability. The RBE approach has lower investment, rapidly plant construction, moderate output and greater versatility, and is hugely adaptable to the market. In current many years, this strategy has been utilized in some developing countries. Nevertheless, due to the lack of assistance in the middle of the upper roll formed by this forming technique, due to its rigidity, the diameter of the formed steel pipe cannot be less than 508mm (20in), which minimizes the market share. Numerous pipelines in China have a diameter below 508mm.
four. JCOE molding strategy
First, the steel plate is pressed into a J form on a hydraulic press. Following pressing the edges on each sides, it is stamped into a C shape by a number of instances. Last but not least, it is pressed into an O form by a semi-O form upper die. The product quality of JCOE method is near to that of UOE welded pipe, and the price of the operation line is considerably reduced than that of UOE unit, but its manufacturing efficiency is reduced.
five. C molding approach
Use two C forming machines to substitute the U and O presses in the UOE unit. The forming procedure is: the pre-bent steel plate is initial formed into half of the steel plate on the very first press, and then the steel plate is formed on the other press The other half to get an O-shaped round tube. The welded pipe developed by C forming strategy is of suitable size, moderate output, and lower cost of manufacturing line.
six. PFP stepwise bending strategy
The steel plate with the end pre-bent is progressively bent on the press with smaller sized methods and far more times, and finally formed into a round pipe by a steel pipe seam welding machine. The PFP method has a little tonnage due to the tiny sum of reduction per time, so the tonnage of the press is not huge, so the investment is also little. Link This technique can form welded pipes with distinct pipe diameters and different wall thicknesses. The processed diameter can be less than 406mm, and the good quality of the welded pipe developed is much better. Very good, reasonable yield.
Tips: Straight seam steel pipe is a steel pipe whose weld seam is parallel to the longitudinal route of the steel pipe. Straight seam steel pipes can be divided into high-frequency straight seam steel pipes (ERW) and submerged arc welded straight seam steel pipes (LSAW) in accordance to the production process. Straight seam welded pipe has easy manufacturing method, high production efficiency, reduced cost and speedy development.
In situation ASTM A53 Grade B in ERW (electrical resistance welded) pipe, the weld seam of A53 ERW pipe shall be done the heat therapy with a minimal 1000°F [540°C]. In this way the no untempered martensite remains.
In case ASTM A53 B pipe in cold expanded, then expansion need to not exceed 1.five% of the necessary OD.
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