Abstract :
MR. D. A. TILT (Chairman, Birmingham Graduate Section) who presided opened a very animated discussion which was taken part in by numerous graduates and visitors. Mr. McNab, he said, had told them that heat treatment consisted in getting a piece of steel with a few crystals in i t ; on heating it, these started running round and round, and in the case of hardening, it was hoped, by quenching at a certain temperature, to catch them where they ought to be, but in most cases of hardening, this point was missed, and the desired results were not obtained.
