COMPARISON OF TECHNOLOGICAL CAPABILITIES OF DIFFERENT MAGNETIZING DEVICES FOR MAGNETIC PARTICLE TESTING

Speaker:
TROITSKIY, Vladimir; The E.O. Paton Electric Welding Institute; Ukraine

Authors:
Borodai, O.; The E.O. Paton Electric Welding Institute of the National Academy of Science of Ukraine; Ukraine
Gorbik, V.; The E.O. Paton Electric Welding Institute of the National Academy of Science of Ukraine; Ukraine
Troitskiy, V.; The E.O. Paton Electric Welding Institute of the National Academy of Science of Ukraine; Ukraine

ID: ECNDT-0095-2018
Session: Surface Methods 3
Room: R2
Date: 2018-06-14
Time: 14:10 - 14:30

The paper provides a comparative analysis of constant magnet magnetizing devices (MD), applied for magnetic particle testing (MPT) of complex geometry parts, Flawtinder and TVA-5 with similar pole sizes and equal number of magnets in each device. The difference lied only in structure of the yoke joining constant magnets. Flawtinder magnetizing device represents itself two columns with magnets joined by flexible cable. Section of ferromagnetic mass of the magnetic column and joining cable differs approximately two times. The magnetizing device with yoke in from of cable is almost broken magnetic circuit. Another magnetizing device TVA-5 is a flexible magnetic circuit on pivots, which has section similar to constant magnet section. TVA-5 devices in contrast to Flawtinder can be easily taken off, since the poles are spring-loaded, and moved over tested object surface.
The tests were carried out on standard specimen following all technological MPT operations. Thus, two types of MD, which can provide magnetic particle testing of parts of any geometry, were compared under maximum similar conditions of work. It was determined as a result of experiment that MD of Flawtinder type with joining cable has not very high indices of defect detection due to very developed normal component Hn of magnetic field. It is known that the lower relationship of normal and tangential components Ht, the higher technological properties of MD are. As a result of tests it was determined that TVA-5 with flexible yoke, section of which equals poles section, has better indices than that in the device with joining cable.
This difference in Hn/Ht value significantly depends on distance between the magnet poles.