Nondestructive testing of wire rope based on shoving magnetic field structure

The methods for wire rope or pipe nondestructive testing commonly include: eddy current testing, radiographic testing, optical testing, acoustic testing, electromagnetic testing, and so on. The structure of electromagnetic testing device is simple, and various types of magneto sensors can be used. In addition, the wire rope belongs to ferromagnetic components, with the application of electromagnetic excitation, the electromagnetic characteristics of the defects are different from the intact wire rope, where magnetic sensors can be used for data acquisition for defect detection. The electromagnetic testing is not affected by the oil or mud stains on the wire rope surface, so the internal and external defects can be detected. The electromagnetic testing of wire rope is common and cost effective for many wire rope operators, and it has been developed and recognized as the most reliable and effective wire rope NDT method [1], [2]. At present, for wire rope or pipe nondestructive testing, usually uses the structure of magnets and a magnetic yoke as an excitation to excite the tested component to saturation state. A magnetic sensor [3] or magnetic sensor arrays [4] are used to pick up the defect electromagnetic signal, realizing the wire rope or pipe non-destructive testing. The participation of the yoke increases the weight of the detection probe and also increases the probe volume. In addition, the wire rope or the pipe is a rod-shaped structure, in order to achieve a better excitation effect, the arc-shaped magnet which is radical magnetizing needs to be designed for magnetization. This is increases the complexity of the magnetization. In this paper, a new excitation method based on shoving structure is proposed to simplify the magnetizing structure, and eliminate the use of magnetic yoke. The whole nondestructive testing probe is more compact and lightweight, at the same time can achieve a good detection effect.