Vaccum heat treatment?

R

riderV3

Joined
Nov 29, 2010
Messages
204
I'm sure the masters here have answers for my questions.

I bought a custom knife and asked the knifemaker some questions regaring the processes he uses, he told me he utilizes vaccum heat treatment.

I've heard vaccum heat treating a blade reduces contaminations but that's as far as my knowledge goes...

So how does the process affect the blade performance?

Pro? Con?

Toughness? Flexibility?

And he uses D2 if it helps.

Thanks in advance!!
 
Very expensive furnace ! Vacuum HT means that in a vacuum you get no scale or decarburization.

Don't confuse this with a steel making process , vacuum melting or vacuum degassing.
 
What he is talkin bout. Is 10 bar vacuum. I have all my Hss done that way. They work great. Nitrogen quench. While blades hang. Reduce warping. Very good. In my opinion. The best. Process. I may go.to doing everything. Like that.
 
Vaccuum HT uses a furnace that is essentially free of any contaminants during the Austenitizing phase of the HT, so it is excellent for keeping impurities out of the steel. The quench in a vaccuum furnace is generally provided by nitrogen gas. Some furnaces have the ability to add the nitrogen under pressure, which increases the quench rate dramatically. Some do not, which means that the quench rate will be slower.

As mete says, these are expensive (and large) furnaces, and I don't know of any knifemaker who has one in-house. They are commonly used by industrial heat treaters.
 
I don't think it "adds" anything to the steel, but it does prevent bad things like warping and decarb as said above. It also allows the maker to do a lot more work pre-HT. Peters' HT does my blades that way and I can go right to finished edge thickness and very close to finished polish before sending them in, because they come back so straight and clean :thumbup:
 
What his answer should have been is, "I send my blades out and have them done by XYZ in their vacuum oven. They come back perfect every time."
 
Just to clarify, vacuum HT does not eliminate warping. Hanging blades is preferable to laying them down, but if they have residual stresses from grinding or other processing, they can still warp.

Also, the more Bars of pressure in the quench, the higher the bill. More bars=more Nitrogen used.

A good vacuum heat treater who likes working with knives and is given good parts to work with can be a beautiful thing.
 
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