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Details of the large-diameter L450 straight seam steel pipe commonly used in industrial projects

Views: 4     Author: Site Editor     Publish Time: 2025-05-21      Origin: Site

L450 straight seam steel pipe is a large-diameter straight seam steel pipe. The following is an introduction to it:


First, the material and performance of large-diameter L450 straight seam steel pipe

- Chemical composition: L450 belongs to pipeline steel. Its main chemical components include carbon (C), manganese (Mn), silicon (Si), etc., and also contain some trace elements such as niobium (Nb), vanadium (V), titanium (Ti), etc. The reasonable ratio of these elements makes the steel have good strength, toughness, and weldability.

- Mechanical properties: "L450" means that the minimum yield strength of the steel is 450MPa, with high tensile strength and deformation resistance, and can withstand the high pressure of media such as oil and natural gas during long-distance transportation. At the same time, it also has good low-temperature toughness and can maintain stable performance in special environments such as cold areas.


Second, the manufacturing process of large-diameter L450 straight seam steel pipes

- Plate detection: The steel plate used to manufacture the steel pipe is subjected to full-plate ultrasonic inspection to detect whether there are defects inside the steel plate.

- Edge milling: The two edges of the steel plate are double-sided milled by the edge milling machine to ensure that the plate width, plate edge parallelism, and groove shape meet the requirements.

- Pre-bending: The plate edge is pre-bent by the pre-bending machine to make the plate edge have a suitable curvature.

- Forming: On the JCO forming machine, the pre-bent steel plate is subjected to multiple-step stamping, first pressed into a "J" shape, then pressed into a "C" shape, and finally formed into an open "O" shape.

- Pre-welding: The formed straight seam welded steel pipe is seamed and continuously welded by gas-shielded welding (MAG).

- Internal welding and external welding: The inner and outer sides of the straight seam steel pipe are welded by longitudinal multi-wire submerged arc welding respectively to obtain high-quality welds.

- Ultrasonic inspection I and X-ray inspection I: 100% ultrasonic inspection and X-ray industrial television inspection are carried out on the internal and external welds of the straight seam welded steel pipe and the parent materials on both sides of the weld to detect the quality of the weld.

- Diameter expansion: The diameter of the submerged arc welded straight seam steel pipe is expanded over the entire length to improve the dimensional accuracy of the steel pipe and improve the distribution of stress in the steel pipe.

- Hydrostatic test: The expanded steel pipes are inspected one by one on the hydrostatic test machine to ensure that the steel pipes meet the test pressure required by the standard.

- Subsequent processing: Including chamfering, ultrasonic inspection II, X-ray inspection II, magnetic particle inspection of pipe ends, and anti-corrosion and coating processes to ensure the quality and corrosion resistance of the steel pipe.


Third, the application field of large-diameter L450 straight seam steel pipe

- Oil and gas transportation: It is a common material for land and offshore oil and natural gas pipelines. Its high strength and good corrosion resistance can withstand the erosion of high pressure and corrosive media during oil and gas transportation, ensuring the safe and stable operation of the pipeline.

- Chemical pipelines: can be used to transport various chemical media in the chemical industry, such as acids, alkalis, salt solutions, and organic compounds. After special anti-corrosion treatment, it can resist corrosion from different chemical media.

- Other fields: It can also be used in mining water-coal slurry pipelines, urban pipelines, offshore platforms, power stations, chemical, and urban building structures, etc., as structural support or fluid delivery pipelines.


Fourth, the advantages of large-diameter L450 straight seam steel pipes

- High weld quality: using a double-sided submerged arc welding process, the weld has good toughness, plasticity, uniformity, and density, and the weld is short, the probability of welding defects is small, and it is easy to achieve non-destructive testing.

- High dimensional accuracy: after overall mechanical expansion treatment, the internal stress of the steel pipe is small and evenly distributed, with high dimensional accuracy, which is convenient for on-site welding construction.

- A wide range of product specifications: it can produce both small-diameter and large-wall steel pipes, as well as large-diameter and large-wall steel pipes, which can meet the needs of different projects.

Hunan Great Steel Pipe Co.,Ltd
Hunan Great Steel Pipe Co.,Ltd is a world-class production and service provider of submerged arc straight seam welded pipe as the first subsidiary of Shinestar Group. Hunan Great Steel Pipe Co.,Ltd pays more attention to in the pipeline engineering research areas as a pioneer of China Petroleum Pipeline & Gas Pipeline Science Research Institute.

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