tempering

R

Reynaldo Garza

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Jul 12, 2009
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My friend told me to look at you tube video by kentucky knifemaker ed wallace. According to my friend, after he took out the blade from the Paragon kiln he quenched it in olive oil to temper. Supposedly he did not follow through with the oven tempering step. Is this possible to temper any steel blade after heat treating to immediate quench? Rey:confused:
 
I'm not sure I understand your last sentence, but a blade that has been hardened and properly quenched but not tempered (drawn back a bit) would likely break or chip in use. There are a lot of those out there because MANY custom knives are never used.

Rob!
 
Reynaldo Garza said:
My friend told me to look at you tube video by kentucky knifemaker ed wallace. According to my friend, after he took out the blade from the Paragon kiln he quenched it in olive oil to temper. Supposedly he did not follow through with the oven tempering step. Is this possible to temper any steel blade after heat treating to immediate quench? Rey:confused:
Click to expand...

I'm not sure I understand the question either, but

I watched this video

http://www.youtube.com/watch?v=7rr_LpRiTJk

He does HARDEN and then skips showing the TEMPERING step.
but
It's not a how to video.

He skips hundreds of other steps too.

It's a sit down, chat, advertisement for the maker, a sort of lifestyle piece that looks like it was made professionally for TV.

and
Olive oil is not as good as Heat treat quenching oil
I would expect a professional maker, who spent the $ on a Paragon oven, should also spend 1/10 of the price he spent on the oven for the correct oil.
 
If it was improperly hardened you could get away without tempering . BUT wothout being hardened properly it wouldn't be much of a blade !!
 
it depends on steel and quenching media. in certain quenching situation, the martensite already started forming, but other part of the blade are still above the MS. and the heat from the steel can self temper the already formed martensite. i have seen old factory employes doing that a lot, they call it "quenching blue/yellow". for example, drop the knife edge down into oil count 7 seconds or so. took it out, watch the color changing on the edge. at this moment, the thin edge should be already below MS, and looks black. but the thick spine is still way above ms and looks red. watch the color changing on the edge. and then quench it in oil again. quenching yellow for better hardness, quenching blue for better flexabilty and toughness.

but i rather not suggest using this kind method to skip tempering. it was only used for those less important tools.
 
this method also has been used to skip tempering.

get 2 media, first one hold its temperature a little below Ms, another one's hold its range of low bainite. quench the blade in the first media and wait until the temperature are even across the blade. then move the blade to the second media for low bainite.

in this case, only part of martensite formed while cooling in the first media. when move to second media of low bainite range, it will temper the already formed martensite while rest of the austenite form into bainite.

however the low bainite's transforming usually can't fully complete. as the blade cool to room temperature. rest of RA will form into martensite again, and this stuff is better to be tempered. but i have seen tools that had been heat treated this way and still have a pretty good preformance.
 
I had a hunch this knife maker did not show the rest of the story. There has to be tempering done after quenching with good oil. Thanks for the info. gentlemen.:thumbup:
 
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