Non-destructive evaluation of magnetic anisotropy associated with crystallographic texture of interstitial free steels using an electromagnetic sensor

Interstitial free (IF) steels, as third generation of deep drawing steel, are used in the automotive industry for applications requiring good formability, strength and a superior surface quality. The formability is achieved by having a desired strong gamma fibre (γ-fibre) crystallographic texture, which is typically measured using EBSD or XRD, and is quantified by measuring the r-value from tensile tests. It is desirable to be able to evaluate the crystallographic texture using non-destructive testing on production material. Magnetic anisotropy measurement is an attractive approach as the magnetic behaviour of steel is known to be affected by its crystallographic texture. A set of interstitial free steel samples, at different stages of recrystallisation process (i.e., commercially cold rolled and annealed to achieve fully recrystallised microstructures and partially recrystallised) and consequently different texture components have been employed to study the measurement and possibility of predicting magnetic anisotropy in IF steels. In order to compare the predicted magnetic anisotropy to the measured values, a finite element (FE) microstructure model that takes into account crystallographic texture was applied.The findings indicate that the deployable non-destructive technique - proposed U-shaped electromagnetic (EM) sensor that can be placed onto a sheet specimen, is promising for a rapid assessment of the magnetic anisotropy in IF steels