Triple quench secrets to be revealed?(or not)

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Originally posted by mete
yesterday I had to chase away a bear that tried to get into the house.

Today I broke the samples - the triple quench appears more brittle.Gave details to Roger.
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A bear! I'm thinking "anything from .270 on up oughta do nicely" and "how do you roast a bear?".

I'm quite interested in hearing results on relative grain sizes and relative brittleness.

(actually, 230gr .45 acp oughta do fine also... if it weren't for those pesky city limits and laws.)
 
Bear meat isn't to bad if cooked right a little
Gammie and it's cource like pork.
boil it first to get the fat out of the meat,
season and fry that stuff :)
I stoot them with either a 30-30 or a 35 :)
we gotta thin them out here so we can deer hunt..:)
 
There didn't seem to be any difference in the grain size between the single ( soak and quench) and the triple quench. However the triple quench appeared to be more brittle .That doesn't make sense ? What I think has happened is that the triple quench never received enough time at the austenitizing temp to fully dissolve the carbide and also not enough time to get a homogenious structure and that can lead to brittleness. My original assumption was that triple quench didn't give enough soak time ,therefore it would be softer ,which worked out .But that also caused brittleness. A good lesson about the fact that relations between hardness and brittleness may not be so simple.A proper soak is very important and grain growth is not the big problem that many think especially with the lower than normal austeitizing temps we used.I am going to try to photograph it but I don't know if that would mean anything to you.
 
mete,
excuse my eglish, far from complete!
Still practising...
Good report too, some questions tough:

Did the balde broke killing the bear?
Did you hurt yoursef, mother bear must be very protective with youngsters!
Which one, single quench or triple was more edge holding in skinning?

To my mind bears love grain, at least big sized grain. But grain structure...?

Happy not to be there, bears like pigs even more than grain! :eek: :eek:

:confused:.....:eek:.....:confused: :confused: :confused:



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(pig)
 
Pig, what is that thing you draw at the bottom of your posts??

Either Mete or I will post the picture of the three broken sample pieces. He originally offered it to me to post and I then offered it back to him because he is the one that did the grain analysis. If he asks again that I do it I certainly will. For now I will say this: to my untrained eye they all looked to be similar or the same in size except that the triple quench is obviuosly quite brittle by the picture.

RL
 
rlinger,

Pig, what is that thing you draw at the bottom of your posts??
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Thing?
Well, do you mean my nice picture with the pigtail and all or the hammer?

Well, above all I am an artist doing someting with computers and blade smithing too time to time.

The hammer has something to do with many level symbolism (this is what the art is all about!).

Pick one or choose some other:
-I feel to be hammered by the God forcing me to learn again to walk from scratch last summer even I did the same 57 years ago to a great satisfaction of my mother at least (and many other things too relearned- meaning wasting time).
-I feel to be hammered also sometimes in this forum (because of the lack of human communication skills of mine, not blaming anybody else).
-Hammer has a lot to do with blade smithing too in general (I have not a power hammer, I really should have one).
-...........:D:D:D

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.........:)
 
Pig, the bear in question is an american black bear which in this case was 2 years old. A that age they are on their own for the first time.He weighed 150-200 lbs so I am bigger than he is. I didn't carve him up ,I just shouted and fired a shot to scare him off. As far as bears eating pigs -- there was a guy in Churchill, Hudsons Bay that thought it would be a good idea to raise pigs commercially -- the polar bears loved them and that was the end of pig raising !!!
 
Mete,
I am afraid for polar bears walking on streets all the time, because I am living in Finland. Now I am horrified, was this your intention? Not very nice of you!
Living as a pig is not easy for sure any case,you can count on me.

:eek:............ :eek: :eek: :eek:

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(pig)
 
AMAZING photo!


and unexpected by me thats for sure!


Now off hand, and to my eye, there seems to be a lot of difference between the single quench sample and the one you quenched 3 times...

so although the single quench matched the HRC number you got with 3 quenches, I would have to say that the other 2 quenches have changed the inside nature of the steel...

I am very happy you guys decided to crack open the steels and have a look, for this does open up more room for understanding on the merits of the 3 quenched blade....
 
DaQo,

Remember though there were no soaks associated with any of the three quenches for the three quench test piece. Just a little longer in the oven could possibly turns things for the better.

No. I am too tied up to go through another series of tests, for a few weeks at least.

RL
 
rlinger...

perhaps you are right,,,I dont know that much about it, however I am very interested in the views all have on the meaning drawn from the test results...

I myself have been back and forth on the worth of the 3 quenchings that I use with my blades. At first I only used 3 quenchings just because Ed Fowler does that in his Bearing-to-Blade movie that I own and review all the time.

However some on the forum seem to show more support for just one Heat treating and quenching..

At first the HRC hardness results seemed to me to support the one-time Heat treatment and quench. After all when the HRC single quench number matched the HRC from the one quenched 3 time, it kinda ment to me "Why did I quench the other 2 time?"

But now after I see the results in the photo of the different knives, it makes me think that "Although I may not understand whats going on, there is a real change happening to the knife blade in a 3-quench heat treatment...

It's too early for me to say that the changes we see in the results of this one test are helpfull, but it does tend to support the ideas advanced by Mr Fowler in the use of 3 heat treatments.

So far, I have to say that I will stick with doing my same 3 heat treatment quenchings I have been doing until I see a better way.

(becides, I Like useing my O/A torch and I like to have the 3 chances to use it on every blade, it's fun, and it seems to work...)
 
Some of the resolution was lost in the posting.The analysis is that the soaked samples show a continuos fracture surface while the triple quench (no soak) show s ,especially on the left side, multiple fracture surfaces which indicates brittleness. The color is due to color balance effects since I used ordinary light bulbs.
 
Thank you Mete very much for doing this for all us. How does the size of grain impress you (or depress you :)). Is it fine enough for our purposes or a bit on the course side?? I have admitted and again do now that my eye is untrained at examining grain size.


DaQo, the samples displayed are (were) rectangular test samples that were not fashioned into a blade or anything that might resemble one; just equal sizes of 5160 steel.

RL
 
Good work mete and rlinger!


Do not be afraid, I am not starting again to advertise the rope cutting tests, I promised not!

After seeing the pictures I did pick up Ed Fowler's book and look at the results of stock removals (nearest to the test samples?)


Results:
single quench (no soak!!) total 163 cuts
triple quench (no soak) total 195 cuts

I understand that comparing soak/no soak is any case a different matter!
So the above results have basically nothing to do with your results. But some small extra piece of information still.




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a short vocabulary:
> stands for the ear of the pig
& stands for the pigtail
\-\ stands for fore legs
 
Pig, thank you for that information and also for an explanation of your symbols. It all makes so much good sense now (the pig symbols).

I have gained I much higher respect for the other white meat since being welcomed to this thread.

I may not have expreseed myself well enough concerning the object of this thread. In fact I do hold much weight in such testing as rope cutting and other simulated field use. I believe I have already stated that I precribe to the belief that there is no test like the field test.

RL
 
Originally posted by DaQo'tah Forge
... but it does tend to support the ideas advanced by Mr Fowler in the use of 3 heat treatments.
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I think you might want to re-read the results. This particular experiment does NOT support the use of 3 heat/quench cycles, at least not the way the 3 quench was done in this particular experiment. The triple quenched sample pics showed fracture mechanics signs of brittleness (those somewhat smoother, "whiter" areas on the left side of pic... those are, per mete's post, "...multiple fracture surfaces which indicates brittleness.").

However, keep rlinger's post in mind:
Originally posted by rlinger
Remember though there were no soaks associated with any of the three quenches for the three quench test piece. Just a little longer in the oven could possibly turns things for the better.
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A little longer soak in each of 3 might turn things for the better, brittleness-wise. It might also cause grain growth if you increase soak time and then do it 3 times... and grain growth reduction was one of the benefits suggested for a short soak at austenizing temp, i.e. the triple quench.

Or, it might yield similar grain size, same hardness, and same toughness, which would suggest it was not an efficient work process. Or... well, you get the idea. Controlled variable experimentation yields clearer understanding.
Originally posted by DaQo'tah Forge
(becides, I Like useing my O/A torch and I like to have the 3 chances to use it on every blade, it's fun, and it seems to work...)
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Having fun with your torch is certainly one potential goal one might have while bladesmithing. Others may have other goals.
 
My goal is to make a blade that is truly "High Performance"

A blade that will cut what it is asked of knives to normally cut.
A blade that is very easy to sharpen yet holds an edge a long time.
A blade that is strong and that it will resist bending.
A blade that will not break.

And a blade that was fun to make.

To that end I have studied what many have been saying about the benefits of pushing a blade to its limits and the ways to do this. I believe that there are many contradictions involved in building the blade I seek to create. Perhaps a balancing act of different aspects will always be part of my knife-making hobby?

The photos of the test steels show us many things, perhaps the knife makers who know vastly more than I will ever know will be able to draw out some more important and overlooked findings, but I see things supporting the use of the triple quenching sequence.

Its just a theory* of mine, but I believe that if Im truly pushing a blade edge to its limits with whatever heat treatments I am using, then that limit is actually brittleness. A blade that is not knocking on the door of being brittle just might have been able to be pushed a bit more.

(*This is just a theory of mine, that happens to be supported by your test results, but I am very interested in learning more about what caused the change within the steel during the extra 2 heat treatments and how this could be used to our advantage in building better blades.)
 
Ed Fowler's name keeps being brought into this discussion as if his processes are being proven/disproven with this test. From my experiences with 5160 following Ed and Bill's instructions for forging and HT, you are comparing apples to oranges. Obviuosly, Ed's knives (old 5160) are anything but brittle. Mine are anything but brittle (I triple quench 5160). I tried to explain in an earlier post that the triple quench was only a single part of Ed's success with his knives. There are a few big variables that were overlooked in this test... Ed uses Texaco Quenchtex type A quenching oil. I have no idea what the quench speed of vegetable oil is but I'll bet it's enough to make a difference since the Type A has a 28 second quench speed. Quench oils of this speed are referred to as a marquenching oil in the reading that I have done. What was the temperature of the quench oil? I quench at around 155-165 degrees. Also, when the quench test was performed, if I remember correctly, Roger was comparing the steel to be quenched to a reference piece. Ed uses a magnet to test the steel for non-magnetic. Was the test piece above, below or just at non-magnetic when it was quenched. Ed quenches on a rising heat just past critical (non-magnetic) It seems like the temperature could make a big difference too. (Just some food for thought on future tests)

Roger, How did you break the test pieces? It seems like they would have been fairly tough based on the 400 degree temper. It looks like they snapped pretty cleanly.

Rick
 
Rick...

Hi this is Daqo'tah!

I'm very interested in the type of heat treating you are useing and how you like it so far?

could you tell me what you do, and in the correct order so that I can copy and see if there are any changes I need to make to my own Heat treatments?

what I do is this: I forge with coal because Im too cheap to get a gas fed real forge yet. I heat the steel red hot and hit it into the shape I am seeking, then as I forge down the tang on the last 10 heats, I quench in cold oil after I finish hitting with the hammer at each heating. This means that i get the steel red hot,,,hit it around a bit to show who is the boss, then dunk the whole blade in the cold oil. This most always starts a few fires, so this is an "Out doors" idea Im tring.

after I am done forging the steel to the correct shape for grinding, I heat 2 times and bring the steel inside a dark room to watch the color changes. Next i heat the steel and alow to air cool and able to handle. Lastly I heat and set in the forge under a big pile of hot ash for overnight cooling.


then after grinding to an oversize condition, I Heat treat the cutting edge with O/A torch 3 different times, quenching in Texaco type "a" heated to 135. alow to cool in oil, then place in freezer for days

I then temper one time in an 350 kitchen oven for 2 hours, alow to air cool..

freeze for days, then finish grinding and etch

so far,,my results have been so-so to great!....I believe my A/O torch work is not as correct,,,I tend to not get the whole blade up to the same temp, and I also dont quench fast enough,I tend to linger at critical for too long as I try to make both sides equal ..

comments?
 
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