Hi Max, I would be more concerned about cast iron exploding, being a barbell weight I would expect it to be made from scrap metal and that means many sorts of metal in the mix. All I know is it just took the edge off a brand new carbide tip and all it did was take the paint off it The main concern was that it might have been too hard and brittle but as it is only spinning with no load on it it should be fine, besides it is up inside the bodyso reasonably protected from any flying bits
