LSAW steel pipe welding quality control measures

Large diameter LSAW pipes, known for their substantial wall thickness, excellent material quality, and process stability, are the preferred choice for major oil and gas pipeline projects both domestically and internationally. However, the weld joints, welds, and heat-affected zones (HAZ) in these pipes are susceptible to various imperfections such as undercuts, porosity, slag inclusion, lack of fusion, lack of penetration, burn-through, and welding cracks, which can lead to quality issues and potential accidents.

Quality Control Measures

1. Pre-Welding Quality Control

Raw Material Quality

Ensure high-quality raw materials are used. Only materials that pass inspection should be allowed on the construction site. Reject any substandard steel to prevent quality issues.

Welding Material Management

Verify that all welding materials are qualified and properly stored. Ensure the baking system is followed and the weld surfaces are clean and free from rust. Check that electrode coatings are intact and free from mildew.

Weld Zone Cleanliness

Maintain a clean weld zone, free from water, oil, rust, and dirt. This is crucial to prevent external weld defects.

Appropriate Welding Method

Select the appropriate welding method and conduct a test weld before proceeding with full-scale welding.

2. Welding Quality Control

Review Welding Procedures

Confirm that the welding wire and flux used match the welding procedure specifications to prevent accidents due to incorrect materials.

Monitor Welding Environment

Supervise the welding environment and implement measures if conditions are unfavorable (e.g., temperatures below 0°C or relative humidity above 90%).

Check Groove Dimensions

Before welding, verify that groove dimensions, including spacing, blunt edges, and angles, meet technical requirements.

Correct Welding Parameters

During submerged arc welding, ensure that the welding current, voltage, and speed parameters are correctly set.

Supervise End Plate Welding

Ensure proper arc length and welding efficiency at the pipe ends. This enhances the quality of the welds at the pipe ends.

Cleanliness During Welding

Ensure all welding slag is cleaned, and check that joint grooves are free from oil, rust, slag, water, paint, and other contaminants.

By adhering to these quality control measures, the integrity and reliability of LSAW pipe welding can be significantly improved, ensuring safe and efficient pipeline operations.