tempering snafu

jspake

jspake

Well-Known Member
so... i have this FRIEND who may have tried to set the timer on his tempering oven for two hours, and MAYBE he didn't set the timer properly. lets pretend that he came back into the shop in the morning and the tempering oven was still going strong. hypothetically, my friend was tempering a couple of rather thin san mai blades with 52100 cores at a temperature of 375F. what advise do we have for MY FRIEND? files skate, but that doesn't tell us the whole story. opinions? truth?

embarrassed,
 
Your friend needs to sit down with a cup of coffee and relax. No harms been done. Just put it through at least one more cycle at 375° then test the edge to see if it's at the right hardness.

Doug
 
In diffusion based metallurgical processes it is always said that temperature=time, however it is never said how much temperature vs. how much time. At tempering temperatures diffusion moves at a glacial pace, but moves all the same. I wouldn't say that there is no difference from blades that only had the standard two hours, but the difference may be negligible or maybe even something you like. For instance, often one has the possibility of gaining some extra impact toughness for the same hardness by adding more time at lower temperatures. 375F is the lower end of the tempering scale, I personally would want HRC reading to verify, but if the file is skating the same as the normally tempered blades, I don't think I would get too worried.
 
thanks a lot, guys. that's a relief. i'm going to get them both ground down a bit more tonight and maybe do some cutting and see if there is anything funny going on before i invest the time in finishing them out with handles. i have a portable ames #1 hardness tester, but i don't think that will be much use, as its san mai, and i could only test the core steel on the bevel. thanks again!
 
ground one blade thinner, put an edge on it and did a fair bit of aggressive testing and cutting. edge flexes with no chipping, it cuts like a dream, and things are looking like i want them to. thanks again everyone for the reassurance earlier today. file that one under "don't do again". i mean, for my friend...
 
You must log in or register to reply here.
Back
Top