Effect of tensile stress on the 3D reversible and irreversible differential magnetic susceptibilities

Magnetic hysteresis loops in three orthogonal directions are measured for a line pipe steel sample while the external magnetic field is applied in a d irection perpendicular to the tensile stress direction. The total magnetiza tion vector is calculated. This tends to the stress direction when tensile stress is applied. The reversible and irreversible differential magnetic su sceptibilities are derived. It is found that the susceptibilities in all th ree directions are enhanced with increasing tensile stress, although the in crease in the stress direction is much larger than in the other directions. (C) 2001 American Institute of Physics.