1. Ultrasonic Testing (UT): The core testing method, suitable for detecting internal defects such as folds, delamination, inclusions, and porosity. It uses high-frequency sound waves to propagate and reflect within the material, analyzing the echo signal to determine the location and size of defects. It has high sensitivity and can achieve automated online inspection.
2. Eddy Current Testing (ET): Primarily used to detect surface and near-surface defects in conductive metals, such as cracks, pinholes, and hairline cracks. It has a fast response speed, suitable for continuous inspection on high-speed production lines, and is particularly sensitive to shallow defects.
3. Magnetic Particle Testing (MT): Applicable to ferromagnetic materials. By applying a magnetic field and sprinkling magnetic powder on the surface, the magnetic traces are observed to reveal surface defects such as open cracks, folds, and scale. It is simple to operate, low in cost, and often used for auxiliary inspection.
4. Radiographic Testing (RT): Utilizing X-rays or gamma rays to penetrate steel pipes and image them, this method identifies volumetric defects such as porosity, inclusions, and looseness. It is particularly suitable for inspecting critical parts of thick-walled pipes. However, the equipment is expensive, and radiation protection requirements are high, so it is mostly used for important pressure-bearing components.
5. Electromagnetic Ultrasonic Testing: A new non-destructive testing technology that can generate ultrasonic waves without coupling agents. It can perform real-time testing on high-temperature, high-speed production lines, conforming to the new YB/T 6297-2024 standard, and is suitable for online quality monitoring of hot-rolled pipes.
✅ According to GB/T 44152-2024, from January 1, 2025, seamless steel pipes with an outer diameter ≥ 6mm must undergo ultrasonic testing within 300mm of the pipe end. Delamination defects with an area > 100mm² are considered unqualified.
