Research on the manufacture of equipment for detecting defects of disjointed, small diameter steel pipes by magnetic flux leakage method

This paper presents a design and pilot fabrication of the EMI (electromagnetic inspection) device to meet the requirements of non-destructive inspection of defects on straight, small diameter, variable drill pipes. The improved feature of this device is to replace the normal Hall sensor with the planar Hall sensor with high sensitivity, temperature and time stability to investigate the magnetic field variation caused by the variation of tube thickness. The test unit for detecting longitudinal defects has a new structure with a magnetic field that is magnetised along the circumference of the tube by an electromagnet. The magnetisation system and the test tube do not need to rotate during the measurement. The EMI equipment is expected to be tested at the Electromechanical Enterprise of Vietsovpetro.