Spiral steel pipe connection skills

Spiral steel pipes, also known as SSAW pipes, are welded pipes made from strip steel coils, extruded at regular temperatures, and welded using an automatic double-wire double-sided submerged arc welding process. The quality of the joint in spiral steel pipe construction directly affects the connection strength and sealing of the pipe. Here are some operating tips and key considerations for achieving a seamless joint without misalignment.

1. Material Preparation

Ensure the surface of the spiral steel pipe is smooth and free from rust and grease contamination. Clean and remove debris and contaminants that may affect the quality of the fit.

2. Joint Design

Choose the appropriate joint form based on actual needs. Common joint forms include flat mouth, oblique mouth, and V-shaped mouth. Select the suitable form according to the pipeline's working environment and requirements to ensure the firmness and sealing of the connection.

3. Accurate Cutting

Use proper cutting tools to ensure accurate and even cuts. The accuracy of the joint cutting directly affects the quality of the joint and the reliability of the connection.

4. Preheating Operation

For thick-walled spiral steel pipes, preheating is a crucial step. Preheating improves the material's plasticity and the welding performance of the joint. Perform the appropriate preheating treatment according to the material's thickness and specifications to ensure joint welding quality.

5. Joint Welding

Select the appropriate welding method and process parameters. Common methods include manual arc welding, submerged arc welding, and gas-shielded welding. Choose the suitable method based on the specific situation and strictly control parameters such as welding current, voltage, and speed to ensure welding quality and joint firmness.

6. Detection and Repair

After completing the connection, conduct a joint quality inspection. Use non-destructive testing methods, such as ultrasonic or radiographic testing, to detect defects and inconsistencies in the weld seam. If problems are found, repair them promptly to ensure joint integrity and connection reliability.

Additional Operating Tips and Precautions

- Cleaning and Deoxidation

Thoroughly clean the joint area from grease, rust, and contamination before welding. Additionally, perform deoxidation to prevent oxidation reactions in the joint area that could affect welding quality.

- Welding Sequence

For longer spiral steel pipes, divide the joint area based on the actual situation and determine the welding sequence. A reasonable welding sequence can prevent welding stress concentration and deformation issues, ensuring the flatness and firmness of the connection.

- Control Heat Input

During welding, control heat input to avoid excessive temperature and welding stress. Excessive heat input can cause deformation and cracks in the joint, affecting connection quality. Control heat input through proper welding speed and moderate preheating to ensure welding quality and joint reliability.

- Quality Inspection

After welding, conduct a comprehensive quality inspection. In addition to non-destructive testing, use methods like visual inspection and dimensional measurement to check the appearance quality, dimensional accuracy, and weld integrity of the joint. Repair or rework any issues promptly.

By following these operating skills and precautions, you can achieve high-quality, seamless joints in spiral steel pipes. Improving joint quality ensures the safety, reliability, and durability of the pipeline system, facilitating the smooth progress of engineering projects.