I have this co-engineer trying to evaluate the result of a particular heat treatment of SA216 Grade WCC. Believe it or not the heat treatment was done for more than 30 hours and he was reluctant about the result and thought the microstructure, chemistry and mechanical properties was badly affected so he asked a metalurgist if there was effect on the properties of the metal and he said none. I just want to ask your opinion about this. Is long duration of heat treatment really affects the properties of your metal eventhough you are within the range of your temperature limits? Perhaps a detailed explanation of what happen within the metal will give us a better understanding of this technical issue.