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Well, I don't think the steel gives a rat rip what our "intent" is. If I forge a piece of air-hardening steel, it's going to be hard after it cools down regardless of my intent. So why is it hard, if it hasn't been heat treated? If I sent it out for analysis, the report would say "heat treated".




I've made forged bar for Jorgenson Steel. Start with 6" bar, forge it down to 3". Only reason is to "refine or change the crystalline/grain structure". All steel starts as a casting and then it is hot worked (rolled) to "refine or change the crystalline/grain structure". Otherwise they would just cast it into bars.


I could take the same A series bar Grant, forge it down and cool it in a way that would NOT allow it to harden...still heat treating? Would ANY change from austenite to any other structure be heat treatment?..be that martensite or pearlite or any of the other "ites"?

As to the 6" bar...once it got above 1250F you changed the crystalline structure...another 300F above that and a floor cool would have refined that grain.
Forging from 6" to 3" does not guarantee the closing of center porosity....it makes it more likely, but by no means guaranteed. Some wonderful openness can survive that reduction due to force penetration and what exactly is moving. I do not think I could hit hard enough with my 3B or the 45 ton press I have to close up center holes in a 6" square (or round for that matter)...heat, die size and such come into play then as well as alloy and a whole host of other things.

Working from the cast ingot is an odd thing as you know.

Ric
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That definition I posted was from the 40's and made a distinction between a general(metal working) definition and a more specific(metallurgy) one.

Do any of you metallgury guys have a modern technical dictionary and if so, would you post the definition(s) of heat treatment here?

I only play at metallurgy, but here's a bit from George Krauss published in 1980:

"The desired results are accomplished by heating in temperature ranges where a phase or combination of phases is stable (thus producing changes in the microstructure or distribution of phases), and/or heating or cooling between temperature ranges in which different phases are stable (thus producing benificial phase transformations)."

George Dieter wrote a whole book about what happens inside metal in response to external forces. (Things like crystal deformation, slip, grain boundry strengthening, strain aging, and fun stuff like that.) No heat involved.

The ASM books give definitions of specific heat treating operations (annealing, tempering, etc.) but a half-hours worth of searching through the ones I have did not turn up a definition for "heat treating" itself. They all seem to assume the reader knows what it is.
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Hey Thingmaker,

Same thing in my 1948 ASM (American Society for Metals) Metals Handbook, it goes way deep into the heat treatment of basically every metal known at the time but still doens't have a clear cut definition of "heat treating" either. Where it starts to talk about heat treating in general it just leaps into specific definitions and doesn't really have "A" general definition.

I think that what we are talking about are really two different things.

One being, "treating something with heat", which would be anytime that something was "treated" with "heat" to produce a desired result.

The other is changing the internal structure of the steel with heat, which from my perspective seems to be a very narrow definition of "treating steel with heat".

So Frank. . . what are you up to?

Caleb Ramsby

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I could take the same A series bar Grant, forge it down and cool it in a way that would NOT allow it to harden...still heat treating? Would ANY change from austenite to any other structure be heat treatment?



A "controlled" cool-down starts sounding even more like heat-treating. Heat-treating could be done to get to austenite rather than from.
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A "controlled" cool-down starts sounding even more like heat-treating. Heat-treating could be done to get to austenite rather than from.


OR placing it in the spare forge with other large forging I just finished with a brick in the front so parts can not fall out and walk away..cause I do not have a safe place on the floor for hot things to cool (melted my tape measure the other day cause I simply set a bar down to cool without looking).

Heat treating could be used to form austenite, but not as an end goal I would think...stopping just short and doing a spheroidized anneal maybe more useful if machining were the next step.

With so much potential for secondary operations and the whole host of effects occurring during, at and after heat is applied one may think books could be written about it. :unsure:

Ric
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Actually the *metal* doesn't care what you call it or what your intent was. Language is a human thing and humans do tend make distinctions. (I've been told the jury is still out on if I qualify as "human"...)

For example the definition of mineral is "A naturally occurring inorganic crystalline solid" So ice in your freezer isn't a mineral; but ice in a glacier *is* although it's the identical stuff!

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Most of the time I just have things furnace annealed, most of the alloys I work with are not suitable for sphearoidizing. Besides it is quite a bit more expensive. Actually I would most often have parts normalized before machining so they would be in the best condition for later heat treating.

Spheroidize Annealing (from Metlab Heat Treat):

Spheroidize annealing is applicable to steels which have more than 0.8% carbon.
Parts are heated to between 1150°F and 1200°F and holding it at this
temperature for a period of time to convert the microstructure.
Essentially, cementite changes from a lamella formation to an alpha
ferrite matrix with particles of spheroidal cementite (Fe3C).
Spherodize annealing is generally done on parts which have been work
hardened, to allow them to be further worked, either rolled in the case
of coils, or drawn for wire. This resulting product has improved
ductility and toughness with reduced hardness and strength. Spherodize
annealing is normally carried out under a protective (endothermic)
atmosphere to prevent oxidation and decarburization.

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Dang me, dang me, Gonna get a rope and hang me. High from the highest treeee, Woman won't you weep for me.
Roger Miller lyrics.

Before you converse with Socrates, define your terms.

Guys, I'm a smith who's been trying to teach a little bit about toolsmithing over the years. I naturally got into something called "heat treatment." Years ago, I read this definition, I know not where. "Heat treatment is the controlled heating and cooling of a metal in order to change its properties." I use this whan talking about our typical normalizing, annealing, hardening, and tempering. Then, in my peanut brain, I was telling myself that forging is also controlled heating and cooling; there is a correct temperature range for each ferrocious metal. I was thinking, "That is the control." Yet, in plastic deformation [which I prefer to call ha ha formation], the grain structure and crystals are moving and changing. "As forged" may be a legit way to deliver some steels, but the internal structure would not be as predictable nor homogeneous as the four aforementioned heat treatments.

I'm tending to agree more with Patrick, along with cogitating my navel. I have the 1966 Forging Industry Handbook which admittedly, is more interested in impression die forging than blacksmithing. Here is a quotation under the heading "Heat Treatment."

"Many impression die forgings produced by hot forging methods are given some type of heat treatment after completion of final forging operations and before machining or ultimate use. Proper heat treatment can produce a forging with optimum grain size, microstructure, and mechanical properties."

This is a little nebulous, but it looks as though the authors considered the "final forging operations" separate from subsequent heat treatments.

I think that I shall continue to emphasize "controlled heating and cooling" as part and parcel of forging, but I won't consider the whole forging process including cooling down to ambient temperature as a heat treatment.

http://www.turleyforge.com Granddaddy of Blacksmith Schools

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Would ANY change from austenite to any other structure be heat treatment?..be that martensite or pearlite or any of the other "ites"?



Ric


That might work for me Ric! "ANY thermal treatment that causes a permanent change from one structure to another, deliberate or otherwise is heat treating". I like it. That will henceforth be MY definition. And now it is "published"!

Oh yeah, I would consider cryo to be heat treating too. Helps if you use the term "thermal" treatment.
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I have a neat little book from 1933, "Iron and Steel A Pocket Encyclopedia" by Hugh Tiemann. This man did tons of research, and under "Heat Treatment" he offers what I think is a thoughtful and for us, an historical perspective.

"Heat treatment; thermal treatment - Heat treatment in its most general sense may be taken to mean the application of heat either to make the metal easier to work by rendering it softer or more ductile or to secure certain desired (and beneficial) changes in its constitution and physical properties generally not in conjunction with mechanical working. By common usage, however, the term has become restricted to the latter application, for which the writer has suggested the following definition:
Heat treatment is the change, or the series of changes, in temperature, and also the rate of change from one temperature to another, brought about to secure certain desired conditions or properties in a solid substance."

This definition helps me, at least, to further define our terms. I believe that the hook here is the use of "desired" and "beneficial." Thingmaker quoted Krauss, 1980, and Krauss used the same two words. The other hook is Tiemann's mention of "common usage." Common usage in 1933 meant that hot working and mechanical working are excluded from "heat treatment."

I've burned up a few pieces of steel in my lifetime, ruined the pieces, to where I had to start over with new stock. I don't consider this a heat treatment, because even though it is a change from good steel to burned steel (oxygenated), it is not "desired" nor "beneficial."

I am plumb tickled that I started this thread, because of all the responses. I'm NOT writing a book.

http://www.turleyforge.com Granddaddy of Blacksmith Schools

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To chime in with my two cents, I've gotten into numerous debates with people over terminology in the past, mostly in other areas of human endeavour, and my basic conclusion is that it is best to accept a word's meaning in the way that it is actually used. When someone says that a piece of metal has been heat treated, I would definitely argue that for the vast majority of people they mean "the controlled heating and cooling of a metal in order to change its properties", as Frank puts it. Could it technically be interpreted differently? Sure, absolutely. But since the purpose of words is to convey a shared meaning, we'd likely be better off going with the meaning most people are using.

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I have always been fascinated by how the definition of a given word changes over time.

One hundred years ago if I said that I saw a gay man conducting a queer experiment last night. Back then, said sentance would meen that I saw a happy man conducting an odd experiment.

Now in the days of wikipedia. . . well here is wikipedia's definition of queer, "Queer is an umbrella term for sexual minorities that are not heterosexual, heteronormative, or gender-binary."

With the specilization that is occuring in the workplace now it doesn't suprise me at all that the general definition of heat treating has been droped for a much more specific one by those who practice metallurgy.

From the definition that Frank found, "By common usage, however, the term has become restricted. . . " and that was back in 1933!

Caleb Ramsby

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Note that in this discussion, I'm not inclined to say what "is", only how I view it.

I believe a process is a process regardless of "intent" or "desire" or "benefit". Gold can be refined and concentrated in nature, but it's still refined. The process of distillation is still distillation whether deliberate or accidental. If I accidentally knock a hot piece of A-2 in my slack tub, it will probably become hard and crack. No intent, desire or benefit, but to me it's still been "heat treated". Sometimes when people are forging a tool, they are warned not to quench it lest it become hard or "heat treated". So if they lay it on a brick to cool don't they display "intent and "desire" for a certain "benefit"? Wouldn't that be deliberate "heat treating"?

How can a process be defined by the emotion we are feeling at the time we do it (intent, desire)?

Gotta say I'm quite enjoying this discussion, can you tell?:rolleyes:

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But since the purpose of words is to convey a shared meaning, we'd likely be better off going with the meaning most people are using.

Most people define "forging" as "faking a signature on someone elses check." It is only we obscure minority who use the word in it's technical sense. This is why technical dictionaries exist separately from general dictionaries.

But, yeah, faking someone else's signature would NOT be the same as using a heat-lamp on sore muscles B)
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