I’ve cut through 3/4 inch plate (only about 1.5” wide) with that graff disk. It took a LONG time but it came out unscathed with no visible wear on the diamond coating…it wasn’t new either.
Interesting video and the conclusion you draw is consistent with our experience. We now also have a diamond disc for metal in our range --> DT 600 ACM! Best regards from the whole Klingspor Team