Metalman
 Hi - I know that this is controversial and one forum member told me a year ago that it can't be.   But I just don't believe it.  Firstly I believe that the changing from austernite to martensite and vise-versa doesn't have to be all or nothing as normally explained.  .Fact is I believe that actually at most of the normal heat ranges of heat treating there is always some of each in a carbon iron alloy..  This ratio just varies as the metal temperature changes up or down..  Emphasis is put on the 'curie' temperature as the minimum temperature to quench or cool down...I believe that this is not true.  I believe that the alloy can be hardened starting out with an annealed sample and just heated up to some temperature shy of the curie temperature, any temperature, and then quenched and some degree of hardness will be obtained.    I know that the normal way is to temper the fully hardened alloy.  I just don't believe it has to be this way.  As I don't believe that all of those little atoms are always exactly like each other at any given time or temperature and doing their thing at exactly the same time. Fact is there is an accepted physics rule that there is never any two things that are really equal - maybe close but not equal.  Just like Doctors or snow flakes, none are created equal.  Just like I don't know of any mathematical formula that renders an exact answer - most (if not all) will give only approximations.  If anyone knows of any other wise, I would like to know.  Just like mathematicians can't prove that two plus two equals four but they can prove that they probable don't.  That bothered me for years because I could'nt understand it...and then one time in the middle of the night I woke up and thought. "Of course". Anywho...
We are all familiar with 'Flame Hardening', but little is said about 'Flame Tempering',  and It just so happens that I have to do some of that tomorrow.  I assume that it may be common with some but I just don't hear much about it being done. I am not talking about that Samori Sword making.  I assume that it can fit right in with knife making.  

         
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Skarzs the Cave Troll
Maybe I'm misunderstanding what you're saying, but. . .

The whole process used is mostly to get the ideal heat treatment. Annealing removes stresses that can cause problems during hardening, and proper temperatures make the best results.
For example, if one heated up an allow above the recommended quench temperature, the steel would harden, definitely. However, it's what's inside that makes the difference. I have had experience with overheating and then quenching. When broken, the grain size was very large and unrefined, unlike the small grain of a properly hardened steel. 

Maybe you are saying that tempering to remove hardness is uneeded? If so, that would probably require testing. Would an underhardened steel perform at the same capacity of a fully hardened and tempered item? Sounds interesting. 
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jmccustomknives
Metalman, there is a blurred window for carbon to go into solution.  Some alloys, the simpler steels, can have a larger window to work in.  But like all theories it has to be testable and repeatable.  So, take L-6 for example, this alloy does have a large window to work but if you look it up you'll see the hardness decrease as temperature before quenching goes up.

Stars, as far as bladesmithing goes there are two different terms, normalizing and annealing.  I sat in on a conversation between two ABS master smiths about the subject.  According to Jim Batson one shouldn't anneal because that can cause grain growth.  Best practice is to normalize and "hot temper" for best grain size.  Normalizing is what gets the steel ready for heat treat.

Rule #10;  "I can make that" translates to; "I'm to cheap to buy it new."

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anvil
metalman, heres some thoughts.

A gent here indicated heat treating is a theory. There are at least two and baring language their processes are very similar. call the first "traditional" and the other "contemporary". Ones based on color equals temp and the other,,, fancy big words equal temp,,, [wink]

Theories are just that.

Second, all those fancy phase change charts are "predictions" of what may happen if you follow certain steps.

Both traditional and contemporary do just that,,, predict an outcome depending on how good you can follow certain steps.

The similarity between both is these steps are the same.

Thus,,,

Forge
Normalize
Anneal
Cold work
Harden
Temper.

One more thought. solid Ice to water is a phase change and a good analagy. If you hold a constant 32 degrees, you get no water and all is ice. Lower the temp below 32 degrees and you begin to get water.
if you start with water and you are below 32 degrees, no matter how long you wait, all you get is water.

Both these theories and the similar processes are based on success and failure done by steel guys for say,,, 3000 years.

Lol,,,
Feel free to reinvent the wheel any time. [wink]

As to the debate,, i do not stand behind the knife makers latest beliefs concerning heat treating. Beyond my own expetience, what i said above are most of my reasons, but not all.

Heres a few more. These are mainly from the knifemakers own "book" by Verhoeven.

First as to grain growth, generally normalizing and grain growth happen at a higher temp than annealing.

Thus,again, generally, normalizing will refine grain and annealing will not cause grain growth.

Second and most important, all the data and predictions in those phase change chartes are derived from a fully annealed piece of steel. Verhoeven states that the farther off you are from this state, the less likely you are to achieve the predicted results.

All of this fits both theories for heat treating.

And, i certainly out of necessity have not annealed my tools. Say scribes and center punches. Both tools i would say are made from thin stock.

They have never held up in my shop by a magnitude like a fully heat treated tool following the above steps.

They may hold up even for a year, but some of my otger small tools have handled daily use for decades.


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Metalman
Skarzs the Cave Troll wrote:
Maybe I'm misunderstanding what you're saying, but. . .

The whole process used is mostly to get the ideal heat treatment. Annealing removes stresses that can cause problems during hardening, and proper temperatures make the best results.
For example, if one heated up an allow above the recommended quench temperature, the steel would harden, definitely. However, it's what's inside that makes the difference. I have had experience with overheating and then quenching. When broken, the grain size was very large and unrefined, unlike the small grain of a properly hardened steel. 

Maybe you are saying that tempering to remove hardness is uneeded? If so, that would probably require testing. Would an underhardened steel perform at the same capacity of a fully hardened and tempered item? Sounds interesting. 

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Hi - The whole process used is mostly to get the ideal heat treatment. Annealing removes stresses that can cause problems during hardening, and proper temperatures make the best results.  Oh yes, of course, no dispute here.  But the industry is constantly trying new methods to help get to that 'better results'.  There is no 'Best'...that has not yet been discovered.  When one says that this is the 'best', then they are saying there is no use in trying to do any better, and we know that this has no merit.  There are heat treating methods that involve many more steps than we are familiar with and take days. 
Maybe you are saying that tempering to remove hardness is uneeded? If so, that would probably require testing. Would an underhardened steel perform at the same capacity of a fully hardened and tempered item? Sounds interesting.
And yes, that is what I am saying.  As far as testing goes, I have seen the results of 'my very limited testing'.  But, I found that it is hard, for me, to predict, but it works .   I believe that in a more experienced manner and in the hands of the experienced, it would be more predictable.  There are many various complicated heat treating procedures that are used in industry.  An example, I worked in the aircraft electronics end my entire working life except for two years, and when the B-70 was being built by North American my next door neighbor said that he practice welding for four years on Titanium that had been heat treated in various ways. And not 'one' piece of his welding was on the first B-70.  We both watched the first B-70 role out for it's first taxi run.  And the B-70 was one big 'expensive' experiment.  As I say, "There is no 'best'.  That hasn't been achieved yet.  When you hear someone say that this is the 'best' you know that they can't be trusted because they know not of what they speak.  

Have you ever experimented much with flame tempering?
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Metalman
metalman, A gent here indicated heat treating is a theory..... Lol,,, Feel free to reinvent the wheel any time. [wink] 
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Hi anvil - Are you saying that heat treating is 'not' a theory', oh my gosh.
I was only familiar with the three phases of water, except for 'dry water', and that is only a term of imagination stretching.  Until I just saw this Youtube about a forth phase.  I will try to attach it here.  He talks about the clouds being part of this 4th phase.  Do you realize that most people have no idea of what clouds are made of...most just think that they are just water vapor.  Oh how untrue.
And to your, (Feel free to reinvent the wheel any time. [wink])  I have been trying to do that all of my life.  At one time I was making a list of things that I had thought of that had come to pass.  I was working for Douglas Aircraft in 1957 when I thought of an idea that they may use.  They jumped on it and within three month they had converted all or at least most of their Aircraft and 'in field retrofits' with this idea.  And this is used all around you every day....used in the whole world...and even on the moon.  And this is using Xenon tubes to make high powered flashing strobe lights.  If one looks into it, this was first used on the Douglas Aircraft starting in about 1957. At least they had not heard of it.  Before that all emergency type lights were with lamps with a little rotating reflector around the lamp.  I hate to use 'all'.
And on my 1957 Chevy Nomad I installed a transistor ignition system that I made myself before they ever showed up on commercial autos.  I recall having my wife help me hold the wire while I rewound a regular ignition coil.  Because there were none.  I think that Mallory first came out with a transformer for these ignition systems.  Oh yes, I felt free to reinvent the wheel.  Can one imagine what things would be like if this wasn't done.
I will just send this Youtube video in a next reply, it will be more simple for me.
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Metalman
Hi anvil - Here is the water video I was talking about..it is way beyond me of course but I can follow along...

I am familiar with the three phases pf water and the 'triple point of water' - different than the phases - you may be interested and surprised.
I have seen these little animals in the wild in the Philippines that walk on water and fish that just come out of the water and walk around. I have read about fish in Africa that walk for miles looking for a new place to live. 
I used to have a plane and play among the clouds.  Actually out of necessity and desire.  Apparently JFK jr. didn't think that was too necessary for him because he took him and two others to their death in the waters off of Martha's Vineyard.  I wanted to have the experience of flying in zero visibility.  I realized that I was doing this completely illegally. Accordingly to this guy on the video, I was flying in the 4th phase of water but I didn't know about that at the time.  I knew that I wasn't flying in water vapor, but just water.  He explains just why the clouds are able to stayed up there.  Since you mentioned water  - I am going to read as much more about water as I can. 
Will this link above turn blue as I send it - I don't know?  I realize that a whole lot of Youtubes are completely bum-dope and useless but I think this guy is for real - still just all theory of course.  Everyone has their own theories.  I am not saying that theories are bad, oh no.  Does anyone really think that someone has drilled down into the earth to say that it is made of molten iron and nickle?  Don't confuse volcanic eruptions with this.  As I say all theories are unproven...otherwise they would not be a theory.  I like that part about a completely free water battery - I will try and build one.
About the current discussions on heat treating around the curie temperature.  I understand what is said about the magnetism changes and just why some have an idea on what causes this change but by golly I haven't seen any of theories nor have any ideas on 'WHY' this may happen.
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Marc
Life s like an onion ... said Carl Sandburg ... 
I say that life is like an onion only because we create more and more layers that add complexity to make it more interesting. 
Everything we see, touch, hear, taste or smell is but some electrical impulses in our brain so ... is it really there? More likely just a sort of hologram we ourselves have created for our own amusement. [smile]
The government cannot give to anybody anything that the government does not first take from somebody else.
Adrian Pierce Rogers
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jmccustomknives
I think we need to define scientific theory.  On can postulate and idea, if it has merit it can become a hypothesis.  A hypothesis can only become a theory when it's testable.  I refer to "heat treat theory" because that is what it is.  It's testable, and demonstrable.  However since we can't see what's going on at an atomic level we cannot move into the realm of law. 

When heat treating steel there is enough repeatable results that it is predicable.  If one says I have a bar of steel with .1% carbon how would it react to heat treat?  If I add .5% chromium, what would be the result?  If I add 1.5% chromium?  If I add 12% and 1.5% moli?  All these are predicable. 

What makes iron special is it allotropic nature and the special relation that carbon can have.  It's not a mystery, or magic.  It does what it does.  We have the privilege of being able to manipulate it.   [wink]

Rule #10;  "I can make that" translates to; "I'm to cheap to buy it new."

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anvil
metalman, a question,,, here's your quote from me.

Quote:
Originally Posted by anvil
metalman, A gent here indicated heat treating is a theory..... Lol,,, Feel free to reinvent the wheel any time. [wink]
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Hi anvil - Are you saying that heat treating is 'not' a theory', oh my gosh.
I was only familiar with th"

Here's what I actually said...

"metalman, heres some thoughts.

A gent here indicated heat treating is a theory. There are at least two and baring language their processes are very similar. call the first "traditional" and the other "contemporary". Ones based on color equals temp and the other,,, fancy big words equal temp,,, [wink]

Theories are just that.

Second, all those fancy phase change charts are "predictions" of what may happen if you follow certain steps.

Both traditional and contemporary do just that,,, predict an outcome depending on how good you can follow certain steps."

I don't care if you read my posts or not but...
Please don't cherry pick my posts for your own needs.

See, if you read my statement on this instead of playing mix and match h, you would see I agree with you. Especially my simple water analogy. [wink]

"Would an underhardened steel perform at the same capacity of a fully hardened and tempered item? Sounds interesting.
And yes, that is what I am saying. As far as testing goes, I have seen the results of 'my very limited testing'. But, I found that it is hard, for me, to predict, but it works ."

You mean your testing has shown that an unhardened piece of tool steel performs as well as one fully heat treated? If so, I would suggest that your heat treating techniques need a bit of work.

As to the rest, you are welcome to your beliefs.

Thanks.
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anvil
Flame tempering. Do you mean differential tempering?
Do you mean by adding heat to the spine of a knife after hardening and control the color run in order to end up with a blade that has multiple different hardnesses?

If so, yes. I do this with all my tools. Rarely with a torch. Mostly in my coal forge.

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Metalman
Hi anvil - Yes, what I was referring to would be differential tempering...and you know, we are just from a different school.  You say that I am cherry picking and I say you are miss reading what I  say.  I do think that we do have a communication disconnect that maybe should just be left to 'wither on the vine'... or 'let our coals go out'.  It is just against my grain and nature to be into any type of discourse  - I will accept the fact that I am from the old school shall we say. So....
I wish you good smithing and I don't want to interfere with any of that.  I can see where anything that I may say 'will' interfere unnecessarily.  You have a good day.
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