In magnetic flux leakage (MFL) testing of hollow sucker rods, several common issues can affect the accuracy and reliability of the results. These include insufficient cleaning of the hollow sucker rods, difficulties in maintaining the inspection probes, low sensitivity to small surface corrosion points, circumferential sensitivity errors, and interference caused by couplings during transportation, which can lead to false alarms in high-precision detection scenarios.

Let's examine these issues one by one. Insufficient cleaning of hollow sucker rods: Proper cleaning of hollow sucker rods is often challenging, especially in winter when conditions make the process even more difficult. Residual oil and dirt inside the inspection probes can significantly reduce detection accuracy. To address this, our company has developed a high-sensitivity "external open" MFL inspection probe for hollow sucker rods by adjusting the magnetization structure and method. The external and open design of the probe facilitates easier cleaning and maintenance, ensuring consistent detection accuracy.

Low sensitivity to small surface corrosion points and circumferential sensitivity errors: The primary defects in hollow sucker rods include surface corrosion points and fatigue cracks, which can lead to rod failure. Corrosion points can occur at any location on the surface, and significant circumferential sensitivity errors during inspection can easily result in missed or false detections. By improving the structural design of the MFL inspection probe and optimizing the internal coil parameters, we have significantly enhanced detection capabilities and sensitivity. The probe can now effectively detect surface corrosion points, material looseness, and fatigue cracks in hollow sucker rods. Additionally, the circumferential sensitivity of this probe is very uniform, providing high levels of detection stability and reliability.

Interference caused by couplings during transportation: When hollow sucker rods with couplings are transported for MFL testing, the couplings can cause interference due to rod oscillation, particularly in high-precision detection environments, leading to false alarms. To mitigate this, we have equipped the main unit of our MFL testing system with conveyor rollers controlled by cylinders. Under computer control, these rollers automatically avoid the couplings, effectively preventing the interference signals caused by coupling-induced oscillations. Moreover, the inspection probe incorporates floating tracking technology, further reducing oscillation interference and achieving excellent results.

These three advancements have been fully integrated into the latest generation of our company's hollow sucker rod MFL testing equipment. The overall performance and technical specifications of the equipment have reached a significantly higher level, ensuring more accurate and reliable inspections.