I know your standards are high and understand your concerns.
However, I believe there is a misunderstanding, possibly caused by a bad choice of words from my side, based on translations from other languages to English.
Traditional quenching and tempering is in an oven where they put in a bundle and heat it up for 10 hours or so.
The quenching is done as usual in either water, oil or any other liquid.
The result is that the bars inside the bundle do not have the same properties as the bars on the outside of the bundle.
Also with traditional quenching and tempering the bars can come out slightly bend which will have to be additionally straightened.
With the induction method each bar is hardened separately and the bar is slowly rotating while heated up. This give an equal throughout hardness on the bar and all other bars from the same batch have the same values. Also, no additional straightening is required so further tension on the bars is avoided.
The advantages are enough for the mill not to use a traditional oven anymore for quenching and tempering.
This is what I have understood and being a sales person and not a metallurgist I apologize for any confusion.
I have found some websites with images and video’s of similar facilities.
http://moderntec.de/wp-content/uploads/moderntec2.mp4
http://www.itg-induktion.de/en/induction-systems/hardening-annealing-and-tempering-systems/bar-steel-hardening-systems.html
I hope it works with the links.
The cracks in the head are only a few CM and acc to the mill, sawing off 50 mm of each side would be enough.
Have you already sawn some of the heads off? If not, can you please check this?