Heat treat/Quench Question

[Steve Nuckels]

I just heat treated a file knife, got it to non-magnetic and plunged it in heated veggie oil, it flamed and came through straight and intact.  My question is, the oil was probably hotter than the recommended 150 degree temp, (my digital thermometer quit on me)   Will the heat treat be ok?

Also, when I temper the blade is one cycle of one hour @ 450 adequate, or sever cycles?

Thanks for any info.
 

[kbaknife]

It's a little hard to say - from a distance. But, you're probably ok.
Since it was a file, and probably a shallow hardening steel, the faster the oil speed the better, and the hotter the faster.
On that, you may have had success.
On the tempering, what you are accomplishing on the first cycle is a little stress relief, along with converting some retained austenite into new martensite - possibly. The new martensite then also needs to be tempered, hence the need for a second tempering cycle.
Do two.
It won't hurt a thing.

[Steve Nuckels]

Thanks Karl.  I soaked the blade in white vinager and then used a scotch brite pad to clean up the steel, looks like the "Hamon" shade.  Is that an indication of success?