Posted by Sarup Chopra on April 16, 2008 at 09:49:04:
In Reply to: queching crack posted by P.K.GARG on April 16, 2008 at 03:47:09:
Both the quench cracks and the cracks due to overheating (commonly referred to as grinding cracks)have an intergranular configuration. In case of quench crack though the crack surface assumes an oxide layer (best identified by EDS) caused by exposure to atmospheric oxygen at elevated temperature. Furthermore, grinidng cracks create untempered martensite. If you can give out your email address, I can electronically send you a pertinent photomicrograph.