Triple quench secrets to be revealed?(or not)

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OK guys, the results are in..

In regards to the HT processes that I outlined earlier in this thread. I just finished destroying, well, almost destroying my test blade and here are my results.

6" blade of 5160 - differentially hardened lower 1/3 of blade in Texaco Quenchtex Type A - tempered at 335 degrees.

-6 full length edge flexes over a brass rod. - No chipping!
-Average of 119 cuts (over three sharpenings) of 1/2" manila rope before it quit!
-1 90 degree flex with 2" of the tip in a vice. - No chipping or cracking.
-12 180 degree flexes with the same 2" of the tip in the vice. Still no chippng or cracking. Still in one piece.
- I wanted to see the grain of the steel so I put the first 3/4" of the tip in the vice and had at it. It looks fine to me without any of the fractures shown in the test steel earlier in the post.
- The blade returned to withing 25 degrees or so of straight after each flex.
- Just guessing but I would say the I had to apply about 30-35 lbs. of pressure to a 2 1/2' cheater pipe to go full flex.

THANKS ED, BILL and SHANE for the direction, coaching and support to my journey so far! You guys have given me a fantastic start by my standards, not to mention the ABS standards. Up next, JS test knife!

There has been a lot of nay sayers to what Ed has published as of late. To those people I say... Get out of the Lazyboy and try it for yourself before you start throwing negative comments around concerning something that you have zero experience. Maybe some of the steps could be altered or eliminated, but then, "why fix something that ain't broke"! It seems to be working incredibly well for me. To steel (pun intended) a phrase from a friend of mine... This blade is "WOW stuff"! At least to me anyways.

Fitzo - You may see Ed's comments as absurd, insulting and obnoxious, others view them as honest. Count me on the I appreciate honesty side of the fence. But then, I'm married to a New Yorker so I'm used to it:D

Later guys,
Rick
 
Science IS application of experience and observation, Roger. The very basis of the development of a bladesmith is experimentation, exactly as Fowler states. Bacon established the scientific method centuries back as "hypothesize, experiment, conclude, rehypothesize".

However, to eschew technical understanding when it is available is ludicrous. Do we have to "know" everything to make a good blade? No, but the more we know the more competent we are.

I spent 30 years developing new pharmaceuticals. We didn't succeed by eschewing detail. I learned that every piece of information is critical to integrate with as much depth of understanding possible.

I don't have any argument with Fowler going about his business as he would. What I do have a problem with is a generalized statement bashing science as a source of learning, or insulting the folks who prefer technical understanding.

I shouldn't have said anything, but I've been pissed since I read that. It simply grates against my pride at being a scientist. So sorry.

Rick, perhaps you'll understand what I'm saying here, perhaps not. I don't think I said anything about Fowler's honesty now, did I? Nor was I in any way commenting generally about him or his methodology. I simply took umbrage at the specific comments against those who would seek a deeper understanding through science. I sorta find that "honest", too.
 
I thinks a little miss reading :rolleyes:
I shall duck and find my pop corn and get some beer:)

I understand what ED is saying, you don't?? to speak for myself
I'll use what works best, not always needing to know just
why it does..and learn as I go
be it acicular pattern ,martensite, phosphorous, undisolved carbides,??

nice to know the terms and some, you don't have to know, to get to the same place, the terms may not be there for me to rattle off.
but I understand more as we go :)

if we explore and record what are we? man had to pound it before he
could record it..salt please..:)
 
Oh, I think I understood, Dan. I actually got pretty good marks in "reading comprehension" back when. :D

I guess unless you've been where I have, perhaps the insult is lost .... Rob had some better commentary than I, but unfortunately he deleted it. It seemed he understood what I was saying.

Sorry I said anything............
 
Greymaker, you miss an important point. "pound before we record " ? I wonder where you think modern steels came from ? They came from metallurgists who used recorded observations, a knowledge of the science of metals and a lot of development work . If you would like to go back to the old way of making bog iron you may but some of us would like to make faster progress.
 
Originally posted by rdangerer
Now this is a learning for me... first I'd heard that super fine grain lowers hardenability...

...What steel(s) did you test in this regard?
Click to expand...

This is one that I didn't need to prove to myself since it has been a proven metallurgical fact since a time even before McQuaid and Ehn verified it and developed testing in order to completely predict it back in the early 1920's.

Here is how it works; it all comes down to that same geeky tech word "nucleation". Diffusional processes (carbon moving about in the steel to make differnt structures) also often need points of nucleation at which to begin transfromations. In the simple carbon steels that we often work with the main inhibiting factor in hardening is the formation of pearlite. If we can just avoid making pearlite at around 1000F. we pretty much have it licked for hardening by making martensite. Austenite is a supersaturated solution of Carbon(cementite) in iron (ferrite) if you cool it all of that carbon cannot stay in solution. If you cool it fast enough it will be trapped in solution (martensite) but if you don't cool it quite fast enough some will seperate out at around 1000F. and make fine pearlite. Here is where nucleation comes in. Smaller grains offer many, many more points of nucleation than larger ones, thus it is easier to make pearlite (or harder to avoid it) in a fine grained steel. Ask any industrial heat treater how he would increase the depth of hardening in a given steel without changing the quench medium and he will imediately say -increase the austenitizing (soak) temperature. Not only does this pull more available carbon into solution but it bumps the grain size up a notch and supresses the formation of pearlite.

If somebody is getting away with quenching oil hardening steels in water they are probably playing with soak temps. and keeping the grain very fine.

Now if you are working with a steel that is more prone to form bainite then the grain size affect on hardenability is not as pronounced, but then the pearlite nose is way to the left anyhow.


..And if you care to, can you comment on grain size and toughness, grain size and abrasion/wear resistance and what you've found in these regards?...
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Grain size has a profound affect upon "toughness" larger grained steels have less impact toughness than finer grained steel. Heat up some 1095 or 1084 until it sparks and then quench it. A very slight tap with a hammer will break it off to show the large sugary grains. Reheat it a few times at a proper temperature to get the grains back wiht int reason and then quench it. You will have to hit is substantially harder to break it this time.

Grain size does not have near the effect on abrasion resistance as overall hardness and carbide precipitates. Lets pick on everybody's farvorite supersteel, wootz, a ancient blade of eastern crucible steel may very well skate a file with no problem and yet only rockwell at around 35-40HRC. Due to the excess of carbides alone the blade would cut for some time on soft targets, but if that edge impacted anything hard it would probably deform. It is true that rockwell isn't everything but it is still an important element in the picture. I have a 10 lb. ingot of wootz that sits on my workbench for a paper weight. It could dull any of my files quite well if I were to go at it with them, but I have easily stamped it with cheap little numerical stamps. Very abrasion resistant, but soft as butter.
 
Kevin, excellent info.

And just like a five year old who keeps asking "why... why"...

So the heat treat is key to many properties.

Assume for a moment you have some 1084 in a size that could be stock-removal ground into, say, a nice big 9" blade. And assume you could also forge down and then grind a nearly identical blade from 1084. So stock-removal vs. forging.

The two blades get the same austenizing heat, same quench, same temper. They Rockwell identically.

Which blade would you expect to perform better on, say, rope cutting, and which would have better impact resistance? And why? Would the answer change with various steels?... L6, O1, 52100, etc?

Obviously I'm driving at the "why bother to forge" question. And if you believe there is a difference, what are the key elements that make forging an endeavor that adds value, blade performance-wise?
 
Originally posted by shane justice
Kevin, great pics! How many smiths you know etch blades as a part of testing?

You mentioned, fine crystals and quench time. Quench media seems to be a variable that hasn't spent much time being discussed. So far, vegetable oil, water, Mobil Vactra and Texaco Type "A". Which about covers the spectrum of quench speeds.

This might be another "How long is your string" question, but in general does the speed of quench media make a difference?
Click to expand...

This one is easily answered. Quench media makes a whole world of difference. But in blades we are always balancing between maximum hardness and workable toughness. I like to lean more towards the hardness with an emphasis on strength and edge holding. But in light of this the fastest possible quench is not necesarily the best. Al you have to do is avoid pearlite and keep it straight, beyond that can be overkill. I have noticed a profound lack of understanding or interest, among many smiths, in the complex chain of events that occur both in the blade and in the quench medium in those few seconds of excitment. If I were to relly get into it this thread could become many more pages in length really quick. To those who love secret potions for quenching let me just leave 2 terms - "thermal extraction" and "vapor point".


On the basic level your thoughts-
"fast quench = very hard, brittle
slower quench =less hard but tougher."

are correct in the sense of avoiding pearlite. But when precise control of heating and cooling rates are available it is possible to get tougher "as quenched" along with maximum hardness. Avoiding the pearlite nose yet not be so brutal in the most stressful phase of martensite formation. I am sure the Type A would be fine but I am sold on my Park #50, Park AAA and, of course, my personal favorite Thermo quench low temp. salts. Which allow me to achieve that tough hardeness.

But a discussion on those techniques could make a entirely new thread to itself and I am not sure what the focus of this one is anymore;) .
 
Roger, mete, Kevin, others...
I apologize for my outburst and interjecting an off-topic criticism into the thread. I had promised myself not to get drawn into the BS commentary by others, but I have failed my self-control.

Please do not let me be the cause of losing interest in this thread, as there has been too much good info to let the rancor of a crabby old bastard like me diminish it.

I won't interfere again, promise.
 
Originally posted by rdangerer
Kevin, excellent info.

And just like a five year old who keeps asking "why... why"...

Assume for a moment you have some 1084 in a size that could be stock-removal ground into, say, a nice big 9" blade. And assume you could also forge down and then grind a nearly identical blade from 1084. So stock-removal vs. forging. The two blades get the same austenizing heat, same quench, same temper. They Rockwell identically.
Click to expand...

Oh my! Variables, variables. Let us assume that this is all done in a fantasy realm where there is no decarb, heating is perfect and precise everytime, no contamination from the fire, etc... , let's face it there is a whole lot less to go wrong with a ground blade, so it has the advantage from the outset. Now I am a bladesmith, mind you, so I have nothing to gain by favoring the stock removal blade, I also have nothing to gain from deluding myself with blind faith in myths. If the finished product was used as a knife, I mean to cut things and not impress folks with how brutally silly we can be with misuse, I would expect to have a dead heat tie in a perfect world. But now let the forged one get some nice pre-heat treatment "attention" in the proper temperature ranges and things could be a bit different.

I would also expect to see no difference on normal impact toughness, but if the shock load could be applied in impossibly odd angles at different cross sections one could see a slight advantage to the forged blade due to the flow lines from the drawing out of the origninal casting being shaped along wiht the profile of the blade. This should be true of 52100, L6, O1 etc... they are all still just steel.


Obviously I'm driving at the "why bother to forge" question.
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Your words "why bother to forge" is indeed at the very heart of all the passions, and mysticism surrounding these questions. We all go through periods of trying to justify why we put ourselves through this forging thing. We think we look foolish for doing all this hammering and heating if the grinder can do it as well, but I think we look a whole lot more foolish by coming up with all kinds of wild claims and medieval mysticism to jusify it. I have finally came to terms with it just fine, I don't need "secret" techniques or magic hammer strokes to justify my preserving such a ancient and noble art as this, I think that justifies it all on it's own. Besides, despite the long hours the dirty air and the burns- it is really too much fun!
 
That seems to me a very fair and balanced response. But, as always, YOMV. ;)

If you don't have fun with it, well, it's a job, and not a passion. Hard to sustain an interest level, and a pursuit of excellence, in something that's "just a job".

Indeed, it is a noble craft, and there is a certain elegance, a certain dignity in such crafts, well, and in fine craftsmanship in general. There are plenty of appealing retro aspects that seem to have redeeming value for various reasons (e.g., old mechanical watches, 60's era Mustangs, Camaro's, 'Vettes, etc).

Of course there are a couple of other reasons to forge which I didn't include in the framing of that question:
1. Damascus (of course, it can be welded in a hydraulic press, and of course there is Damasteel... but you get the point)
2. availability of certain stock sizes for removal
3. certain blade shapes may be more efficient to just forge than do a bunch of bandsawing and grinding.

Thanks for offering your opinion.
 
Originally posted by Kevin R. Cashen
But now let the forged one get some nice pre-heat treatment "attention" in the proper temperature ranges and things could be a bit different.
Click to expand...
I promise, my last question ... at least for tonight:

A few sentences to elaborate on the above quote would kind of complete the picture for the moment.
 
Anyone ever compare a "properly" heat treated and martempered blade with one given the Fowler Triple Quench?


Seth
 
Originally posted by rdangerer
A few sentences to elaborate on the above quote would kind of complete the picture for the moment.
Click to expand...

I kind of thought that I left that one ambiguously open to misinterpretation. Since most of the benefits that we percieve are are from forging are actually just heat treatments (normalizing, cycling) with some hammering going on, if we percieve it as that and use the last few heats to our advantage, we can set things up for the final heat treatment in a way that the grinder cannot. But we could still do this without the hammer being in the equation at all.

I have always looked at the hammering as "misdirection" in this whole "forging a better blade" business. Misdirection, as in the magician who has you entirely focused on the antics of his right hand while his left hand pulls off the real trick. As smiths we are so focused on our hammer blows that we forget about the heat we take every time. The hammer is just moving metal, making noise and putting on a good show but the heat is really making the changes.

A good example is the comments I made previously about carbide banding making patterns. Sometime in the past some smith, somewhere noticed that it occured when he hammered at a lower heat, being a smith he naturally assumed that it was the hammering, and not the fact that it was done at a lower heat ( which really doesn't make sence since the hammering is the same and only the heat is different). But it has become widely believed that it is a result of physical deformation, when in fact you don't have to touch it with anything but heat to get those effects. Well wait, it would be fair to say that you do need to hammer it to change the look of the banding and manipulate the patterns, but diffusion doesn't give a rip about your hammer, but it does do snap to attention for heat though.


1. Damascus (of course, it can be welded in a hydraulic press, and of course there is Damasteel... but you get the point)
2. availability of certain stock sizes for removal
3. certain blade shapes may be more efficient to just forge than do a bunch of bandsawing and grinding.
Click to expand...
Thank you for pointing these out, every one is very valid and I couldn't agree more.
 
Passion of forging ? My college thesis involved making steel, forging it, heat treating it etc. None of my classmates did anything like it. Their's were mostly very esoteric often involving more solid state physics rather than practical metallurgy. But one thing was always very obvious - when I cranked up the old forging machine there seemed to be an audience, standing there watching in awe as if some deep seated passions had been awakened. I'm sure that those of you that have forged things, perhaps at renaissence fairs have experienced the same thing.
 
Fellas,
It is half past three and my day is just starting. Forgive me if I ramble a bit.

A few years ago I took a technical writing course at the local college. The gentleman who taught the class haad been employed as a writer of computer manuals. He was the guy who broke down the information form "tech-ese" to english. It was his asserion that the folks who had built the computers, hardware and software, were not able to communicate the specifics of computers to the common man.

It seems that difficulty exists in other arenas as well.

Ed offered a different view point, using different ideas. What a damn shame.

Kevin Cashen bridged a lot of gaps in the science of metallurgy. He brought the knowledge and he brought applications. Kevin, If we ever meet the first round is on me.

Now it's quarter to four and I have to get to the shop.

I wanted to add a quote from my current read. Before going to sleep 5 hours ago, I opened to this exact page and read...

"Every movement, every evidence of search is worthy of the student.
The student must look things squarely in the face, know them for what they are worth to him.
Join no creed, but respect all for the truth that is in them.
The battle of evolution is going on.
There must be investigations in all directions.
Do not be afraid of new prophets and or prophets that may be false.
Go in and find out. The future is in your hands."
~ from "The Art Spirit" by Robert Henri.

This quote is for my friend Rick, who showed the courage of a true student, when he posted his test results on this thread. In the process, Rick wrecked a great blade. Way to go Rick!

OK guys, have a good one! Blades are calling!

Shane
 
It's too early for this PC stuff...

In my last post...CORRECTION!!!!

I said...
"Ed offered a different view point, using different ideas. What a damn shame...."

I edited without reading... it should go on to say ..." What a damn shame that nobody refected on those ideas before commenting."

My apologies for the typo...

COFFEEE MUST HAVE COFFFEEEE!

Should I really be in then shop today?

Shane
 
Yeahup:)

OK comment.... now that I got your attention
no I didn't miss a thing it's all here :)
Originally posted by mete
Greymaker, you miss an important point. "pound before we
record " ? I wonder where you think modern steels came from ? They came from metallurgists who used recorded observations, a knowledge of the science of metals and a lot of development work . If you would like to go back to the old way of making bog iron you may but some of us would like to make faster progress.
Click to expand...
edited to add ((basic things)) maybe as simple as the color Grey or the name Gray:D

Mike your getting personal hahaha

you still missed it at least what I tried to convey.
yes yes yes we NEED technology I know that, anyone does that wants to think about it
and make progress.
what you missed in my post is that we had to start somewhere (that's why the pound it first and record it )( it started there)

I spent a long time in auto mechanics along with many other things
and it was very easy to over analyze and miss the basic things and if you did the rest did not help a hole lot.

I'm not a writer as you can see, I'm damn lucky I got through school..
so I lack the words for explaining properly what's meant .
part of this was in an e-mail
I sent the other day

I know all Makers are at different levels (and we need to know)

you can take the best steel in the world (if there were one) and IT not be worth zip, if not heat treated properly
and the same for a Mild steel that can only be case hardened it's still only going to be a cheap butter knife
with even the best of heat treats

you know this and I don't need to tell you .
( I know it seems petty but we still have guys that are just starting out)

there are many factors that can keep a blade from being just as good as it can be and of course we don't know it all yet
and never will but I do believe that the steel industry has the technology to know what they are talking about, the one's that
are in this field using that technology...
but
The fact that everyone over looks,( basic ) is that we are at the mercy of the steel that we get
( i should say most makers)

For one
I may get some O1 at .85 or as much 1.0 or more carbon,
which one is better for a blade you and I both know which one
but we don't know what we are getting when the factors change with a + or - limit like that and that is just carbon,

and we get what we get and we (at least I) can't even be sure of what we have most the time other
than sending the stuff out to be tested all the time.

we are a middle man on the steel line,, doing with what we get.
that's why I like the study of the old masters that made there own steel they added their own carbon to what they
wanted and saw fit. most of us have to try an keep what carbon we have IN the steel with out loosing it
because of just that heat that gets just a bit to hot to many times.... many many factors..

I was a tool a die maker years ago and I had to learn to heat treat and temper, I started in the early 70's
in a shank factory, what we did was, make shanks for shoe and each one had to be heat treated
this was what we did,, we made our own dies to stamp out the shanks on 50 ton presses
the hole thing was based around heat threading,,

..I can tell you a bit about pig iron because I live in a town that mined iron ore
years ago I helped the wife do a collage paper on the subject and the business of it.

I have a blast listening to the threads on the subject
and get a chuckle out of some of it..and form my own opinion of it all .. I.,,, by a long shot don't know it all
don't claim too
and never will , I'm still learning.
from pig Iron to today OK whack me again:( :confused: :D
 
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