Pages 507-508
Non-destructive evaluation techniques have become more important for high reliability of power plant structures. For the weld zone of austenitic materials, e.g., austenitic stainless steel and nickel-based alloy, fully effective ultrasonic inspections are difficult due to beam skewing and attenuation arising from its complex acoustical anisotropy. In order to evaluate the acoustical characteristics of austenitic steel, velocities of ultrasonic wave are measured for single crystals of nickel-based alloy and directionally solidified alloy. Measurement values of velocities agree with numerical results based on the transversely isotropic model, which is based on the assumption of random orientation distributions around the solidification axis <100>, with an accuracy of about 3%.
