CIVA as an Aid to Understanding Ultrasonic Anisotropy in Steel

Abstract

Standard calibration blocks to assess beam paths and configure data displays using ultrasonic instruments use low carbon steel with isotropic acoustic properties. However, industry is trending towards the use of high tensile steels where the acoustic properties are anisotropic. When an ultrasonic system, calibrated on an isotropic steel reference block, is used on anisotropic steels, the beam can be bent, skewed and attenuated so that the reference setup is rendered useless. CIVA simulation software can be used to aid in understanding the effects on the data displays. As well, CIVA can help to demonstrate the degree of change that can occur when the acoustic velocities are established for the fast and slow shear modes in an anisotropic steel.