Manufacturing Defects of SSAW Steel Pipe

1. **Weld Defects:**

- **Incomplete Fusion:** This occurs when the weld metal does not completely fill the space between the pipe edges, leaving gaps that can become points of failure.

- **Porosity:** Caused by gas pockets trapped in the weld, which can weaken the joint.

- **Cracking:** Hot cracking or cold cracking can occur due to rapid cooling, high welding heat input, or material impurities.

- **Undercutting:** Material removal beneath the weld bead, which can reduce the cross-sectional area of the weld and weaken the joint.

- **Spatter:** Small droplets of molten metal that are ejected from the welding arc and adhere to the surface of the pipe.

2. **Shape and Geometry Defects:**

- **Warping:** Uneven heating and cooling can cause the pipe to warp, affecting its straightness and roundness.

- **ovality:** The cross-section of the pipe may not be perfectly circular, which can lead to uneven stresses on the pipe during operation.

- **Taper:** The diameter of the pipe may not be uniform along its length, causing a taper that can affect the structural integrity.

3. **Surface Defects:**

- **Scaling:** Excess oxidation that results in a rough surface texture on the pipe.

- **Pitting:** Small holes or pits on the surface of the pipe, often caused by corrosion or improper cleaning processes.

- **Surface Cracks:** Microscopic or visible cracks on the pipe surface that can grow under operating conditions.

4. **Material Defects:**

- **Inclusions:** Non-metallic particles or slag that are trapped within the steel during the manufacturing process.

- **Segregation:** Uneven distribution of alloying elements within the steel, which can lead to localized weaknesses.

- **Hardenability Issues:** Some steel grades may harden excessively when cooled rapidly, leading to脆 issues and reduced toughness.

5. **Dimensional Tolerance Deviations:**

- **Wall Thickness Variations:** Inconsistent wall thicknesses can lead to uneven stress distribution and potential failure points.

- **Length Tolerance:** Length variations can be an issue if the pipes are not cut to the specified lengths required for a particular project.

6. **Testing and Inspection Defects:**

- **Non-Destructive Testing (NDT) Failures:** Defects that may not be visible but are detected through NDT methods such as ultrasonic or radiographic testing.

- **Hydrostatic Testing Failures:** Pipes that fail to pass hydrostatic tests due to leaks or other structural issues.