Illustrate elastic anisotropy columnar dendritic vs equiaxial grain structure and its response to ultrasonic test in case of austenic stainless steel?

Answer 1

Quite a mouthful here. First, dendritic inclusions are, by definition "random" when they occur. They can follow any axis of crystal structure, and, depending on the nature of the dendritic intrusion, can work "through" the crystal rather than along any axis of its structure. That kills about half the question. The idea of "equiaxial grain structure" in austenitic stainless steel (or any other kind of steel) is almost certainly incorrectly applied here. The crystalline structure of the steel will be defy ultrasonic tests for grain structure because the grains will be too small, will lie well beyond the resolution powers of ultrasonics. Certainly ultrasonics are used to look for inclusions and flaws as well as cracks and macrostructure deformation. But there are severe limits on what can be seen. Ultrasonics will not show anything on a small scale. Microstructure is best examined with x-rays and electron beam microscopes and other tools of micro-inspection.