Development of an Electromagnetic Acoustic Testing System for Tank Floor

Speaker:
WU, Xinjun; Huazhong University of Science and Technology; China

Authors:
Hu, J.; CNPC Research Institute of Safety and Environment Technology; China
Li, W.; CNPC Research Institute of Safety and Environment Technology; China
Luo, Y.; Huazhong University of Science and Technology; China
Wu, X.; Huazhong University of Science and Technology; China

ID: ECNDT-0128-2018
Session: EMAT
Room: G2
Date: 2018-06-13
Time: 14:30 - 14:50

The above ground storage tank is one of the most important equipment in the oil and petroleum industry. Because it contains hazardous materials, its accidents not only interrupt the process but also contaminate environment. The main reason for storage tank failure is floor corrosion, As an efficient nondestructive testing method,the magnetic flux leakage testing method has been widely used in tank floor inspection. However, it is difficult to obtain the accuracy plate thickness. In this paper, the nondestructive testing system is developed based on the electromagnetic acoustic transducer. The aim of this method is to overcome the shortage of the existing electromagnetic method. Firstly, Electromagnetic ultrasonic shear wave testing method is adopted because its propagation speed is slower than the longitudinal wave. When the transverse wave is carried out on the metal plate, the high thickness measurement sensitivity can be obtained. Then, the electromagnetic ultrasonic shear wave testing sensor, including the permanent magnet and coil, is developed. Based on the orthogonal experimental principle, the finite element experiment plan is designed, and the finite element model of the electromagnetic field, the force field and the sound field direct coupling method is established. Parameters of the permanent magnet and coil of electromagnetic ultrasonic shear wave sensor are obtained. In the last, an electromagnetic acoustic testing system for tank floor is developed. The mechanical structure of the scanner is designed. The voltage signals from the testing sensor are amplified and converted to digital signals, then uploaded to the portable computer through USB interface. The laboratory tests indicate that this system performance can meet the field requirement.