Wally Watts Heat Treat Method 440C

heatride

heatride

Joined
May 15, 2003
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Maybe someone else out there might need this info. I talked to Wally Watts on the phone he was very nice as always, called him a few times over the years. Anyway here is his method of Heat Treating 440C.

Double Wrap Blade as air tight as possible
Add a piece of paper towel to burn any oxygen left inside foil
Put knife in oven cold
Bring temp up to 1850 and hold for 1 hour
Then air quench let blade cool to about 150 Degrees then
Temper at 300 for 2 hours then cool to room temp
Temper at 300 for 1 hour for double draw

RC will be at 58-60

And Mike your right about Paul Bos but all the file work and things I do I am scared of the freight companys to and from the heat treater.
The only reason I am going to treat my own blades is just because of fear of loosing them via freight.
 
Originally posted by heatride
Maybe someone else out there might need this info. I talked to Wally Watts on the phone he was very nice as always, called him a few times over the years. Anyway here is his method of Heat Treating 440C.

Double Wrap Blade as air tight as possible
Add a piece of paper towel to burn any oxygen left inside foil
Put knife in oven cold
Bring temp up to 1850 and hold for 1 hour
Then air quench let blade cool to about 150 Degrees then
Temper at 300 for 2 hours then cool to room temp
Temper at 300 for 1 hour for double draw

RC will be at 58-60
Click to expand...

how long is it taking his oven it reach 1850 from cold?
this I believe will make a lot of difference in the final Rockwell.
it could be a long soak time in a slow oven over critical..
 
Graymaker I dont know how long from cold it takes Wally. It takes mine about 45 minutes. If you have any info on this please respond its all new to me.
 
Sounds good and thanks for sharing. The only thing I would not do is the double wrap. Makes it more difficult to get a rapid quench. A tight single wrap will do it if you take care not to get pin holes from the blade point and such. And you could insert a cryo between quench and temper if you liked.

Roger
 
I won't question others results ,,, too many little variables..
I don't use much 440C but I heat treat it almost the same as
154CM,, 440c is hardened at less than 100 deg's
lower on the top end then 154cm or ats34 is.
I bring the oven up to temp. put the blade in, wrapped,
let it come back up to temp again from the loss of
heat from the oven being opened up.( about 100 deg's on mine)
let soak for 15 min. then pull it out and put it into a coffee
can and blow compressed air around it to cool it faster
while in the wrap. I double wrap but the inner one is just a
boat wrap for the blade to sit in, from an older One time used
foil. I'm not seeing much difference, full double wrapped or not.
I will say if you leave 154cm (and the others may do the same)
in to long it will mess you up. I soaked 154cm for 2 hours
then quenched it took way more temp to bring down the Rockwell
and it had very open grain , you can't mirror polish it and have
it look right. this is just my test results
and opinions on how I do it.
 
Dan,

Interesting tip on the coffee can. Might have to try that one. I've been clamping foil pack at back of tang in a machine vise and forced air quenching. Your method would more cause the flow to hit all surfaces uniformly. Lately I am coiling the compressor hose and laying that coil in a water/ice bath to sink motor heat out of the air. It makes a marked difference in air temp..

Roger
 
Roger
I do it that way because it's fast and a sure quench
with out removing the blades from the foil.
I stand there with tongs in one hand and the air hose in the other.
this way I can pull out 4 or five blades if I have to,,
put them in the can while blowing the air in. it's
not very confiscated but works well..
my compresser has a big tank so I don't have a heat problem.
about 80 gal I think.
good Idea though
be carfully not to cool too fast
you don't want cracked blades.:( :)
 
I toss the foil wrapped blade into a woodworkers vise and crank it down. Brings the temp down fast. After letting it sit for a couple of minutes I then air quench the rest of the way, sometimes spritzing with a little water. I let it cool completely before unwrapping.

I thought 440C needed 1950F??? :confused:
 
1880 on my chart
but 1950 may be ok but,you may have to adjust your draw temp
to get the your desired rock...:confused:
is the vise helping keeping the blade straight too ?
I put them,once cooled somewhat on my magnetic vise
it's surprising how cool the S/S can
be and the magnet not grab it. this is the time you can do some bending :eek: :eek:
 
The vise does help keep it straight but you gotta watch it. If you crank down too hard you'll imprint your foil on the blade. I always make sure I wrap them ultra neatly with all folds on the ends and not overlapping the blade at all so there's just one layer of foil between the jaws and the blade and nothing else.
 
It escapes me how a tapered tang and tapered and beveled blade can be clamped in a vise, so as to uniformly sink its heat and straighten - even if only the blade portion is clamped for that purpose(??). It has been in my thoughts about how to do this for a few weeks now. Obviously, to my thinking, it is the edge portion that is most essential in the quench.

Roger
 
I have a question about the way the blades set in the oven
I know most are layed on there sides.I had a couple blades done by another
maker and I had a 14 1/2 inch knife that came back with a bad warp
in the tang.The tang was not stressed in no way,I spoke with Palu Bos
about this and he said that some knives that are layed on there sides will warp during HT.Paul said he hangs his blades when they are getting HT
to take away from any chance of that problem ariseing.He Was so kind he told me to send him the blade and he would heat treat it again
and straighten the tang for me,I have alot of work in this knife
and I am glade be could help me out.
Has any one put argone gas in there foil when HT there blades
Roger have you ever thought of tapering your tangs after HT
I tried on one of my prototypes and I like it better than tapering
before HT,there is not flex in the tang and it come out much better.
now if I could just get some good pictures of these knives I have been working On:grumpy:
 
Nathan,

I almost always have had to straighten the tangs after heat treat. Regardless of tang tapered or not has seemed to make little diffrence as to warp, and I would rather taper annealed than hardened. Tangs are rather easy to straighten because there usable hardness is not normally essential to the knife performance. It is the blade that is not to be comprimised. To straighten, I tightly clamp (in a machine vise - smooth jaws to best sink heat) as far back on the tang as possible and put a house hold propane torch to the warp. Doing it the first time or two is scary but all works well and I no longer worry about RC devaluation of the blade. Sometimes you have to clamp at the ricasso. Clamp her tight in a big smooth jaw vise and pore it to her.

Paul Bos has been very kind to all us as far as I can tell from what I have seen here. He has answered a couple my requests from my simply posting them here. Although I have not yet tryed to phone him, I am sure he would display a certain patience for me.

As a side note: I have been wondering that a hanging blade would be much less apt to warp than a lying one. My Evenheat does not allow me to do that, except that I am toying with the idea of setting her on her end so that the door would open from above. I'm thinking about it.

Roger
 
Since I only make folders and I do my grinding after heat treat, warping is really not a big problem for me. I certainly don't have to worry about tapered tangs and if I do I'm in trouble! :p
 
I use an evenheat too.
I use a fire brick the white soft brick and cut groves in it
to set my blades into. spine down. even heat both sides.:D
 
I make folders also and was talking to A T Barr the other day on the phone and he mentioned he grinds after the heat treat. What are the advantage's of this ? I have always ground mine down then HT . But you are the second person that makes folders that told me this and I think I read it about another maker. Would you please give me some info on this. Thanks in advance.


Glenn Dykes
Louisiana
 
I don't not make folders but I think the reason that most folder makers
do that is if they do get any warp after HT they can go back and
surface grind it so they can get the tolrance they need to get a good fit up.I may be wrong but I see were it would help folder makers out.I think this would also get away from the warpage problem
the steel has not be stressed in anyway therefore they can get around
any problems
 
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