should this happen with Bainite?

T

the possum

Joined
Jul 31, 2002
Messages
2,954
I've been testing and using my latest Bowie a lot lately, and have had some experiences that don't seem to correlate with everything I've read about Bainite. This knife is ground from 5160, 24" long, classic Sheffield style blade shape with a long sharpened false edge, swell center coffin handle.

One of the first days I used it, I noticed a chip missing from the edge. (the chip was ~.3mm deep and located about 8" in front of the guard- less than halfway down the blade) The only thing I thought I ever chopped with that portion of the blade was saplings. I figured I just must have hit something else and not known it. Later, when I was dispatching a wounded raccoon, I got another chip in the belly of the blade from the bones. (I was careful to avoid the teeth) And last week I was clearing some weeds around the farm when the sharpened false edge came in contact with an old milk can laying in the grass. This time, it took out a chip .7mm deep and 4mm long. (it took considerable sharpening to remove, and slightly changed the blade profile) Granted, it did hit steel, but I was only using a very light wrist cut- not a full power swing from the arm.

I may be over reacting, except my old Bowie made from ATS-34 encountered these same situations MANY times, and was never damaged this badly. The thing that concerns me most, is that from everything I read, I expected Bainite to dent and roll at the edge rather than actually chip away. Or were my assumptions wrong? Should this be happening?
 
I'll bet you don't have bainite. BTW if it is sharpened why do you call it a false edge ?
 
Gaben, I know the common accepted terms it's just that I find it a strange use of english to call sharp ' false '.
 
interesting
I've made (and still do) old time replicas with false edges
and have been asked to sharpen some of them.
I've always thought it was just what it says, it's faults because
it is an edge but just not sharpened.
and thought a swage is more on the decorative side to look like a faults edge
but angle of it would not make for a good edge..:( :confused:
 
I would expect Bainite to be untouched by what you described. I think that your bowie had some heat treatment problems.
 
Originally posted by mete
Gaben, I know the common accepted terms it's just that I find it a strange use of english to call sharp ' false '.
Click to expand...

Short "false" edge as opposed to the "true" long edge. Has nothing to do with sharp. :)
 
I agree with feth, the heat treat has problems. One of the reasons I use 5160 for bowies and short sword like objects, is because they will forgive a lot of poor treatment. What you described should not be happening. Try the brass rod test!
 
Can you describe your heat treatment process to achieve bainite? I was under the impression that it took up to ten hours being held at temperature above the nose of the curve (around 800 degres F?) in order for bainite to form.

Is it possible you have some form of mixed structure that includes untempered martensite in a pearlite or partial bainite matrix?
 
Bainite is achieved by quenching in salt at about 500F (depending on the steel) below the nose, just above the Ms temperature and held for hours until bainite transformation is complete. O1, L6 and 5160 are suitable for this process (austempering ). Yes you can get mixed structures.
 
Mete, I have HT'ed a Matulis in the same manner you described. It was in 5160 and I abused the poor thing something awful. It held up well and that's what has me thinking Possum's knife is brittle for some reason.
 
Thanks for the info and the link, I certainly have some catching up to do! That's what you get for not watching the forums closely.
 
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