How long does a quench last?

[Webber]

I know what quenching is (in very basic terms!) but I though that quenching would be dipping the blade in warm oil until the blade has cooled.

Apparently I was wrong...

How long do I quench the blade for before I can start tempering?
It's 01 steel.

Thanks in advance.
p.s. obviously a bit of a newbie so please, K.I.S.S. (keep it simple, sirs. ).

[Sam Salvati]

The blade should be quenched until it is cool to the touch, then tempered.

[Knife-Man]

The blade should be quenched until it is cool to the touch, then tempered.

that's what I always thought . oh dear have I been doing it wrong ?

[Webber]

Maybe I'm getting a little befuddled, if that's the case, can someone explain this bit (second page about the quench being "complete") to me?

[John N]

Heat the blade untill a magnet doesnt stick to it, quick into the oil (the quench) it will cool in 10 - 15 seconds.

It will then be brittle, so you TEMPER the blade. This can be done by putting it in a domestic oven set to 200c ish for an hour or so.

Lots more to it, but thats the basics!

[Knife-Man]

"These must be tempered as soon as the quench is complete. Delay in the case of 01 will give rise to cracks appearing in the untempered steel."

Just isn't true .. I waited from strait into the oven to tempering weeks after hardening without any cracks at all .. except perhaps micro fractures which I cant see.

It is true that after hardening blades are in a very highly stressed state and should be tempered immediatly to help AVOID cracking ... but not totally necessary... just desirable

[jamiemackie]

I normally remove the blade as soon as the oil stops boiling but while the blade is still too hot to touch with bare hands. This keeps me a few precious moments to check for warps and straighten if needs be before the steel is fully formed into martensite. Some say that you have five minutes to do this after the quench but that is mainly lies, ive tried straightening like 1 mintue after quench and had a blade snap.

Blades can crack if left too long after quench. If you just straight quenching somthing like O1 in oil then you will most likey be fine but if youve water quenched 1095 with clay then its best to get it tempering pronto. I know of a few people who have had blades crack hours and even mintues after quench when the blades were sound immediatly post-quench.

Jamie

[Webber]

Thanks folks,
I've done a few blades now, all 01, and none have cracked so i was a little confused.
Much appreciated.

I have another question but I'll put it on seperate thread to avoid further uncertainty!

ATB, Del.

[Raggedstaff]

"When the quench is complete" simply refers to the transformation of austenite into martensite. The idea of quenching is to effect this transformation within the steel. This article would have you believe that if you do not go straight for the tempering cycle the second you have effected this transformation your blade will break.

As you can see other people's experience would seem to disagree. When I was doing this professionally I would forge a number of blades in a day and take them all home in the evening to temper them in the oven. I through hardened and I differentially hardened without any cracking later. I almost always quenched in water, or if I was being a pussy water for 2 seconds and then oil. If a blade was going to break it did it in the quench. If it survived the quench it survived full stop.

Except that lovely wakizashi I snapped trying to take out a bend...

Give it a try. See what your experience is and take pics so we can all learn from you.

Oz

[ggfh666]

I've had plenty of cracks. But only at quench time. Not any later.

[jdm61]

My understanding is that you can straighten a quenched blade until it drops down below about 400F. You can also give a blade a slightly new set if you take it out of the tempering oven, bend it in a vice to where you want it and then pour water on it. However, that will only allow you to correct VERY slight problems.