why Surface is harder than core but no carburization?
why Surface is harder than core but no carburization?
(OP)
we did some normal thru hardening job on 8740. the surface is 1 or 2 point (RC) harder than core. microscope shows no sign of carburization. why this happen? what we can do?
thanks
thanks





RE: why Surface is harder than core but no carburization?
How many hardness traverses did you perform for actual comparisons? Also, the surface will still cool more rapidly in comparison to the core for thru-hardening steels. If what you report is correct, it could simply be that the martensite adjacent to the surface contained less retained austenite, in comparison to the martensite formed toward the core.
RE: why Surface is harder than core but no carburization?
RE: why Surface is harder than core but no carburization?
another thing is that the parts, washers, are only two coins' thickness. i am not sure if cooling transformation (i.e. surf cools faster than core) is an issue here.
any comments and ideas?
thanks
RE: why Surface is harder than core but no carburization?
RE: why Surface is harder than core but no carburization?