Status analysis of API 5L seamless steel pipe

API 5L seamless steel pipes feature large diameters and thick walls, making comprehensive ultrasonic and eddy current testing essential for detecting internal and surface defects without blind spots. This involves rotating the steel pipe while moving the detection probe forward, optimizing space and detection efficiency.

Globally, magnetic flux leakage and hydrostatic testing are common. In China, domestically produced magnetic flux leakage equipment is inadequate, often requiring expensive imports. Hydrostatic tests are labor-intensive and less efficient.

The metallurgical industry primarily uses tank ultrasonic testing and through-coil eddy current testing for pipes up to φ160mm. Larger diameters pose challenges, as traditional methods are less effective and national standards prohibit some approaches. Independent ultrasonic tests also have limitations, including blind spots for certain defect depths, affecting overall reliability.

Key Points

- Ultrasonic and Eddy Current Testing:

Ensures "no blind spot" detection by rotating pipes and advancing probes.

- Testing Methods:

Magnetic Flux Leakage: Efficient but costly due to reliance on imports.

Hydrostatic Testing: Labor-intensive and less efficient.

- Challenges:

Large Diameter Pipes: Difficult to test using traditional methods.

Blind Spots: Inherent in some ultrasonic testing methods.

- Current Practices:

Up to φ160mm: Tank ultrasonic and through-coil eddy current testing.

Above φ160mm: Standards restrict traditional eddy current methods; alternative methods are needed to improve reliability.

Conclusion

Effective testing of API 5L seamless steel pipes, especially large-diameter ones, requires advanced, reliable methods to overcome the limitations of current practices and ensure comprehensive defect detection.