LSAW steel pipes are divided into high frequency resistance welding and submerged arc welding according to the welding process. Longitudinal submerged arc welding is called LSAW and longitudinal high frequency resistance welding is called ERW.
Compared with submerged arc welding, high-frequency electrical resistance welded steel pipe (ERW steel pipe) does not add welding material in the ERW welding process, and the weld does not form a hot melt state, and the weld metal undergoes a recrystallization process. Therefore, the formed seam fully corresponds to the chemical composition of the base metal. After the steel pipe is welded, it is annealed to generate internal stress during cold working and internal stress during welding. Therefore, the comprehensive mechanical properties of ERW steel pipe are better.
The submerged arc welded (UOE) longitudinal pipe adopts the cold expansion process after welding to expand the pipe, so the geometric dimension of the long seam submerged arc welded pipe is more accurate, and the matching quality when using the long seam submerged arc welded , pipes well, which ensures the quality of welding. Eliminate some internal stress. In addition, the longitudinally welded submerged arc pipe is welded by multi-wire welding (three-wire, four-wire). small. After multi-wire welding, the first welding wire can eliminate welding stress, thereby improving the mechanical properties of the steel pipe. The base material can realize 100% ultrasonic inspection of the steel sheet, which meets the requirements of the high pressure pipeline for the base material. However, although the overall performance of LSAW pipe is superior to other steel pipes, its high price deters users with limited funds.
1. Difference between raw material and production capacity The raw material of ERW steel pipe is hot rolled steel coil, while the raw material of LSAW steel pipe is hot rolled steel plate. Therefore, ERW steel pipes can ensure the continuous operation of the assembly line, high production efficiency and low production cost, while SAW steel pipes are made of steel plate, which cannot ensure the continuous operation of the assembly line, low production efficiency and high production cost. ERW steel pipes are limited by the thickness of the steel coil. Generally, the maximum thickness that can be produced is 25mm, and the maximum diameter that can be produced is 660mm; The maximum thickness that can be produced with LSAW pipe is 40mm, and the maximum diameter that can be produced is only limited by the width. from steel plate. The maximum production diameter is 1422 mm.
Submerged arc welded longitudinal pipes are divided into different forming methods: UOE steel pipe: after one steel sheet is pre-bent on the edge, it is subjected to U-forming, O-forming, internal welding, external welding and mechanical cold expansion. JCOE steel pipe: pre-weld according to “JCOE”, forming, cold expansion after welding. HME steel pipe: according to “CCO” mandrel rolling method, cold expansion after welding.
2. Differences in Welding ERW steel pipe does not need welding wire, LSAW steel pipe needs welding wire.
3. Difference in appearance. The inner and outer welds of ERW steel pipes need to be removed to promote corrosion protection, the extra height of the inner and outer wall welds of LSAW pipes is not conducive to corrosion.
4. Difference between purchase cost and complexity The purchase cost of ERW steel pipe is low, while the cost of LSAW steel pipe is high, and the overall price difference is 15%-25%. There are few manufacturers of LSAW pipes in China and it is difficult to purchase them. When the diameter
Post time: Apr-10-2023