Eddy Current Testing and Ultrasonic Testing of Steel Bars

If the bars are going thru a thermal change - infrared cameras may see a defect of a size and depth. The velocity that the inspection will be performed at is also needed to be described, where in the process and what changes is the material going thru will help to get better definition and answers to your question.

I have a chart assembled by NASA where they did comparitive testing between infrared, ultrasound, and other methods on non-ferrous materials, but the technology is the same.

These are steel bars of various chemistry normally low alloy and plain carbon steels, coming out of Bar rolling mill at higher temperature of say 500 to 750Deg c or after cooling to room temparature.

We want to check sub-surface defects as well as internal defects .