Title :
Nondestructive detection of dislocations in steel using a SQUID gradiometer
Author :
Kasai, N. ; Ishikawa, N. ; Yamakawa, H. ; Chinone, K. ; Nakayama, S. ; Odawara, A.
Author_Institution :
Electrotech. Lab., Tsukuba, Japan
fDate :
6/1/1997 12:00:00 AM
Abstract :
We have developed a magnetic flux imaging system. The magnetic flux image (MFI) shows the distribution of magnetic flux density over a plate like specimen. The change of the pattern in the MFI by tensile deformation has been investigated in a carbon steel without applying magnetic field using the system. A clear striped pattern appeared after deformation by fine plastic strain between 0.2 and 1.0% before strain-hardening. Luders bands, which are groups of slip bands, appeared on the plate surface and were observed at the corresponding locations of the stripes in the MFIs. This shows that the fine deformation is nondestructively detected using the MFI.
Keywords :
Luders bands; SQUID magnetometers; carbon steel; dislocations; ferromagnetic materials; flaw detection; magnetic flux; magnetomechanical effects; plastic deformation; slip; Luders bands; SQUID gradiometer; carbon steel; fine plastic strain; magnetic flux density distribution; magnetic flux imaging system; nondestructive dislocation detection; plate like specimen; slip band groups; strain-hardening; striped pattern; tensile deformation; Coils; Degradation; Magnetic field induced strain; Magnetic field measurement; Magnetic flux; Magnetic materials; Magnetostriction; Plastics; SQUIDs; Steel;
Journal_Title :
Applied Superconductivity, IEEE Transactions on
