Weld seam inclusions of SSAW steel pipes

During the forming process of spiral submerged arc welded (SSAW) pipes, various factors such as incorrect edge alignment, edge thickness variations, forming seam gap changes, and bridge oscillations can impact welding quality, leading to defects like inclusions and pores. These defects are more prevalent in thick-walled SSAW pipes compared to thin-walled ones, weakening the weld's effective cross-sectional area and reducing the welded joint's plasticity, toughness, and overall performance. This article outlines methods to prevent weld seam inclusions in SSAW pipes.

Methods to Prevent Weld Seam Inclusions

- Quality Control of Raw Materials:

Ensure high quality of raw materials such as strip steel and welding wire, with strict control over the inclusion content.

Properly store welding wire and coils to avoid contamination from oil stains and rust.

Dry the flux according to process requirements and maintain its cleanliness and uniform particle size.

- Minimize Raw Material Bending and Width Changes:

Avoid manual hard bending and reduce changes in raw material width and delivery position.

Adjust the position of the vertical rollers to keep the strip steel edges flat and minimize extrusion, ensuring a stable forming seam.

- Maintain Disc Shear Blades:

Properly adjust the side clearance and overlap of the disc shear blades and replace blunt blades promptly to ensure they are in good working condition.

Adjust the height of the welding pad roller to avoid forming seam issues caused by excessive roller height.

- Optimize Production for Thick-Walled Pipes:

Select appropriate groove forms and angles for thick-walled SSAW pipes.

Use a double milling device for edge trimming and milling to improve edge processing accuracy and the forming seam state.

- Select Reasonable Welding Process Parameters:

Maintain a good weld shape coefficient and avoid narrow and deep seam gaps.

Use sufficient heat for welding to ensure slow cooling of the molten pool, increasing agitation and promoting the surfacing of gases and reactants.

- Adjust Internal Welding Spot Position:

Position the internal welding spot away from the occlusal area to ensure a stable seam state and reduce the impact on internal welding.

- Optimize Flux Feeding Position:

Position the flux supply port close to the solder joint to minimize the chance of flux entering the forming seam.

By implementing these methods, the occurrence of weld seam inclusions in SSAW pipes can be significantly reduced, ensuring better weld quality and enhanced performance of the steel pipes.