The production process of Longitudinally Submerged Arc Welded (LSAW) steel pipes involves several steps that are essential in creating high-quality welded pipes used in various applications such as oil and gas transmission, structural support, and construction. Here is an overview of the typical production process of LSAW Steel Pipes:

1. Plate Preparation:

The first step involves the preparation of steel plates that will be used to form the LSAW Pipes.

High-quality steel plates are inspected for defects, cut to the required sizes, and then shaped into the form of a pipe through a bending machine.

2. Edge Milling:

The edges of the steel plate are milled to ensure they are smooth and perpendicular to the surface, enabling proper alignment during welding.

3. Pre-Bending:

The steel plate is pre-bent to form the required curvature before welding, which helps in achieving the correct pipe shape.

4. Forming:

The pre-bent steel plate is then formed into a cylindrical shape using a U-O forming press, with the edges meeting to create a longitudinal seam.

5. Internal Welding:

A welding machine with a submerged arc welding (SAW) process welds the longitudinal seam on the interior side of the pipe.

This welding process ensures a high-quality weld with deep penetration and excellent strength.

6. External Welding:

After the internal welding is completed, the external side of the longitudinal seam is welded using the SAW process.

The external weld provides additional strength and integrity to the pipe.

7. Ultrasonic Inspection:

Ultrasonic testing is performed to check the weld quality, detect any defects, and ensure the integrity of the welded joints.

8. X-ray Inspection:

X-ray testing is carried out to further examine the welds for any internal defects or anomalies that may compromise the structural integrity of the pipe.

9. Expanding:

The LSAW pipe undergoes an expanding process to achieve the desired outer diameter and wall thickness specifications.

10. Final Inspection:

The completed LSAW steel pipe undergoes a final inspection to verify that it meets the required specifications, including dimensions, weld quality, and overall structural integrity.

11. Surface Treatment:

The surface of the LSAW pipe is treated with coatings or paints to protect it from corrosion and enhance its durability, depending on the intended application.

12. End Processing:

The ends of the LSAW pipes are cut and beveled as needed to facilitate welding or connection with other pipes or components.

13. Hydrostatic Testing:

After the final inspection, LSAW pipes undergo hydrostatic testing, where water or another liquid is pumped into the pipe at high pressure to check for leaks or weaknesses.

This test helps ensure that the pipe can withstand the intended pressure and fluid flow without failure.

14. Cutting to Length:

Once the pipes pass all quality checks, they are cut to the required lengths based on project specifications.

Precision cutting ensures that the pipes are ready for installation without further modifications.

15. End Beveling and Surface Treatment:

The ends of the pipes are beveled to allow for smooth welding connections and to remove any sharp edges that could interfere with assembly.

Surface treatment, such as coating or painting, is applied to protect the pipes from corrosion and extend their service life.

16. Marking and Packaging:

Each pipe is marked with essential information such as size, grade, and manufacturer details for easy identification.

The pipes are then bundled, strapped, and packaged securely for transportation to the project site.

17. Transportation and Storage:

The finished LSAW steel pipes are transported to the designated location for installation.

Proper storage practices are followed to prevent damage and maintain the quality of the pipes until they are ready for use.

18. Installation and Welding:

Once on-site, the LSAW pipes are installed according to the project requirements, with careful attention to alignment and proper support.

Welding connections between pipes and fittings are made using appropriate methods to ensure leak-free joints.

19. Testing and Commissioning:

After installation, the entire pipeline system undergoes testing to verify its integrity, including pressure testing and leak detection.

Once the system passes all tests, it is commissioned for operation.

20. Maintenance and Monitoring:

Regular maintenance and monitoring of the LSAW pipeline are essential to ensure continued performance and longevity.

Monitoring for corrosion, wear, and other issues helps prevent failures and ensures the safe and efficient operation of the pipeline over its lifespan.

The production process of LSAW steel pipes involves precision manufacturing techniques, quality control measures, and adherence to industry standards to produce pipes that meet the performance and safety requirements of various applications. Proper handling, installation, and maintenance are crucial to maximizing the service life and functionality of LSAW pipelines in infrastructure projects.