The Logic of Heat Treating Oils

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OK, I can't resist -- I'm going to stick my kneck out (I'm new at this, so please use a sharp, relatively painless ax :) )

Years of experience and great training (that I don't have, I readily acknowledge) can lead one to the ability to torch and/or forge heat treat a blade and get what has become known as a "high performance" knife. This is obvious by the testing of blades that has been done time and again.

But...

Let's say, hypothetically, we have a steel that rigorous scientific, laboratory analysis and testing (the kind of testing that is WAY beyond the ability of a smith to do) shows will achieve optimal strength/cutting ability etc. for blade purpose X when heated to exactly 1475 degrees at no faster than 100 degrees per hour, soaked (for 1/4" steel) for 8 minutes, then quenched to drop below 450 within 1.5 seconds, then held at 425 for 15 minutes, then cooled to 120, then tempered at 425 twice (this is hypothetical, so don't get the axe out yet:o )

Using this steel, we have bladesmith A use high-tech lab equipment to heat treat using the exact parameters the scientific experiments showed would create the optimal blade for use X. We have bladesmith B, who has extensive experience heat treating with forge and/or torch, and who's blades are renowned for their superior performance in use X, heat treat with their usual forge/torch methods.

The odds of bladesmith B hitting the scientifically proven "best" heat treatment are virtually impossible. Even A will have a tough time being exact, unless he has some great equipment.

All other things being equal (and I mean ALL OTHER THINGS), when both A's and B's blades are tested, and judged against performance criteria applicable to use X, I can only see 3 possible outcomes:

Outcome 1: A's "controlled heat treat" blade will outperform B's "skilled artisan heat treat" blade, because A's methods more accurately matched the "ideal" for the steel and purpose.

Outcome 2: No discernable difference will be found in testing, because the difference between B's method, and A's was not measurable in real-world blade use.

Outcome 3: B's blade will outperform A's blade, because the scientists are out to lunch.

I find it hard to believe that outcome 3 could occur. That leaves 1 or 2.

OK, you can get your axes out now...my kneck is on the block...what am I missing here? Is my logic flawed? Please be gentle...:(
 
"I would add,, different steels are like the use of different tools. 5160 is a spring steel and I would venture to say that in the use that you described above is H/Ted a bit differently than for use as a knife as we know it.
other steels are good too good going on your find.."

You would be wrong in your venture! It's not H/Ted as a spring at all! It's heat treated HARD! I'm familiar with the anhydrous knife they make, how they make it, and how they use it.
 
"I've always wondered, how do you know when its time to change your quench oil. I use 3 gallons and its just as clean as it was when I started using it, it doesn't flash fire or smoke any different either. So how do you know?"

Bill, many of the companies will provide literature or advice on "scheduled maintenance." Most of what I have seen simply involves adding additional new oil to compensate for drag out and decomposition. But--thinking of cars and such--a complete "oil change" must be necessary at some point. I'm interested to read what the guys who really know something write:)

John
 
Chant said:
OK, I can't resist -- I'm going to stick my kneck out (I'm new at this, so please use a sharp, relatively painless ax :) )

Years of experience and great training (that I don't have, I readily acknowledge) can lead one to the ability to torch and/or forge heat treat a blade and get what has become known as a "high performance" knife. This is obvious by the testing of blades that has been done time and again.

But...

Let's say, hypothetically, we have a steel that rigorous scientific, laboratory analysis and testing (the kind of testing that is WAY beyond the ability of a smith to do) shows will achieve optimal strength/cutting ability etc. for blade purpose X when heated to exactly 1475 degrees at no faster than 100 degrees per hour, soaked (for 1/4" steel) for 8 minutes, then quenched to drop below 450 within 1.5 seconds, then held at 425 for 15 minutes, then cooled to 120, then tempered at 425 twice (this is hypothetical, so don't get the axe out yet:o )

Using this steel, we have bladesmith A use high-tech lab equipment to heat treat using the exact parameters the scientific experiments showed would create the optimal blade for use X. We have bladesmith B, who has extensive experience heat treating with forge and/or torch, and who's blades are renowned for their superior performance in use X, heat treat with their usual forge/torch methods.

The odds of bladesmith B hitting the scientifically proven "best" heat treatment are virtually impossible. Even A will have a tough time being exact, unless he has some great equipment.

All other things being equal (and I mean ALL OTHER THINGS), when both A's and B's blades are tested, and judged against performance criteria applicable to use X, I can only see 3 possible outcomes:

Outcome 1: A's "controlled heat treat" blade will outperform B's "skilled artisan heat treat" blade, because A's methods more accurately matched the "ideal" for the steel and purpose.

Outcome 2: No discernable difference will be found in testing, because the difference between B's method, and A's was not measurable in real-world blade use.

Outcome 3: B's blade will outperform A's blade, because the scientists are out to lunch.

I find it hard to believe that outcome 3 could occur. That leaves 1 or 2.

OK, you can get your axes out now...my kneck is on the block...what am I missing here? Is my logic flawed? Please be gentle...:(
Click to expand...
I just trashed a lot of post..
Outcome 1: A's "controlled heat treat" blade will outperform B's "skilled artisan heat treat" blade, because A's methods more accurately matched the "ideal" for the steel and purpose
Click to expand...
controlled heat treat by the skilled artisan ,,
is just what he is doing by watching the steel, you could record the heat at
the time of quench but would do little good because of other factors
it's what the steel is doing when it's ready that tells you it's ready, that I can't put on paper , it's not really the timing it's what and when the steel is ready which does take some time. I can't explain it but I could show you..

it's the quench you want to stick each time, the temper is for what use you want the blade for,
I think sometimes we lose sight of that in the arguments. JMHO
 
alexmin said:
Not to steal this thread... do you know any good online Metallurgical reading for a newbie. I'll be buying an oven soon and want to educate myself a little bit first.

Alex
Click to expand...

Hi Alex,

Here's a good basic introduction:

http://mse.iastate.edu/files/verhoeven/7-5.pdf

John, Kevin, et al,

Great Thread! Parks 50 and AAA all the way here. I didn't find it hard to get though...just got together with 4 other makers and placed a bulk order for 5 gallons of each type for each of us...they were happy to send it...

:)

-Darren
 
John Frankl said:
"I've always wondered, how do you know when its time to change your quench oil. I use 3 gallons and its just as clean as it was when I started using it, it doesn't flash fire or smoke any different either. So how do you know?"

Bill, many of the companies will provide literature or advice on "scheduled maintenance." Most of what I have seen simply involves adding additional new oil to compensate for drag out and decomposition. But--thinking of cars and such--a complete "oil change" must be necessary at some point. I'm interested to read what the guys who really know something write:)

John
Click to expand...
John
in cars, one of the oils duties is to catch the carbon from the burn gas that has slipped by the rings into the base, changing it is the only means of getting it out of the engine,..unless it leaks out on it's own:D

the high detergent oil keeps it in suspension for this reason, with the oil we use it should just sink to the bottom keeping the oil fairly clean,,

I think Ed Fowler some where said some of his is years and years old..

. I'm interested to read what the guys who really know something write
Click to expand...
I heard that
 
I've gone away and thought about it some more (thanks Dan)...I think I'm beginning to understand...

The problem with my example above was the assumption that the high performance blade for use X would be a blade hardened equally all over. This is not the case, of course. Different hardnesses must exist over different portions of the blade (and tang). Edge quenching can be used by "A" with the "controlled" process (but at a loss of "lab control"), as can heating the spine, using clay, other differential tempers etc. (again, all at a loss of "lab control"), but "B", as an experienced artisan, can play the heat over the blade to acheive a more optimal "spread" of hardness, given the blade's purpose, AND edge quench for that matter.

Thus A cannot achieve the optimal blade without giving up some control somewhere in the process, and B, in a sense, by developing better control of the uncontrolled processes (here's where art and experience come in), often (usually? -- remember, B is a master of the art!) ends up with a better performing blade.

Am I beginning to understand, or am I still missing something?
 
Dan Gray said:
wellcome to the dark side Luke :D
sad with the Darth Vader voice :)
Click to expand...

Damn. I started out hoping I could get real good, real fast by forking over the money for an evenheat. Guess I should spent some time playing with fire first. Then, if I do get an oven, I'll at least have a better understanding of how to use it. Guess there's no quick path to mastery (there never is, is there :o )
 
John, I have experienced some difficulty communicating with computers. Don't worry, our seconds will arrange the details in Eugene.

Changing quenching oils: A simple oil, and I speak of Texaco Type A, has no additives, just simple oil. Therefor it does not wear out, I compared a blade quenched in new oil and one from oil that has quenched every blade I have hardened since 1980 (?) and there was no difference. It is the additives that change and soon the oil is not the same anymore. "veterinairy grade mineral oil in my experience is lighter than Texaco Type A. I have tried to get a straight answer as to what it is and vet. specks do not speak to heat treat specks.

As usual I will state that all comments I make about oil, heat treat, tempering, forging etc. apply to my 52100 and 5160 done my way and I make no claims as to other steels or ----.
 
kbaknife said:
"I would add,, different steels are like the use of different tools. 5160 is a spring steel and I would venture to say that in the use that you described above is H/Ted a bit differently than for use as a knife as we know it.
other steels are good too good going on your find.."

You would be wrong in your venture! It's not H/Ted as a spring at all! It's heat treated HARD! I'm familiar with the anhydrous knife they make, how they make it, and how they use it.
Click to expand...

please reread what I said
I said the steel is a spring steel
I didn't venture to guess how they heat treat it,
I would think they know the way that they want it treated
and do it that way..the mass behind the edge will make all the differance in the world as to the use of the steel...
 
Chant said:
Damn. I started out hoping I could get real good, real fast by forking over the money for an evenheat. Guess I should spent some time playing with fire first. Then, if I do get an oven, I'll at least have a better understanding of how to use it. Guess there's no quick path to mastery (there never is, is there :o )
Click to expand...
don't give up on the oven
like I said with the O/A I'll only do at most about a 6 maybe a 7 inch blade
it depends on the mass of it.. Oven is a good thing too, another toy to play with :)
 
Oooh boy! You know there are about a thousand different tangents that this thread could spin off into at this point, so I think I will just let my comments on the original topic stand for now.;) :D

But I would like to clarify something should I ever get the itch to play with 52100 and some new techniques. Ed do you heat treat all of your blades using the torch or are some heated in the forge as well? Is it torch for both the 5160 and the 52100?
 
Kevin: Always the torch and naturally the magnet and a thermometer in the oil and with the same lighting. I figure you knew all the rest, other than the torch, just wanted to keep the others in contact with what I hope we are talking about.
 
Thanks for the quick concise reply Ed. The lighting is a VERY good point, I still connot believe the number of technical texts that describe temperatures by color, with no consideration for variations on lighting that each shop may have. Although newer texts don't do it, older metallugrical texts had a real nasty habit of using terms like "cherry red"
 
Chant: I don't know much about an even heat, but if it is anything like a Paragon, you have a real valuable tool at your disposal. I could never have achieved what we have without the qualities of the Paragon. There are many other methods, if you have seen my Video you saw my grandmothers house oven in use. The Paragon, what a sweetheart, with her help I can experiment with repeatable heat to 2,000 degrees, ramp up at any rate I choose, hold at any temp for as long as I wish, then repeat it the next day or next month with confidence.
 
Ed Fowler said:
.......The Paragon, what a sweetheart, with her help I can experiment with repeatable heat to 2,000 degrees, ramp up at any rate I choose, hold at any temp for as long as I wish, then repeat it the next day or next month with confidence.
Click to expand...

Shucks, that's EXACTLY why I use my furnaces instead of a torch. Science and technology are my friends. :) To each their own...

Interesting thread.
 
I'll get a third degree from this I'm sure but it will be the last time I try to explain what I see it to be..

I think some miss a valuable point about using the torch for heat treating,
some can't do it this way and never will.

it's as simple as talking politics or religion if you don't see or understand it.
it's just not so,
.. so it gets BOOOO BOOOO hang the witch ..

some time ago Kevin, I think it was? mentioned knocking on a piece of steel while it was quenching Hot and watched the steel shimmer inside,

not a perfect quote but similar,, what's happening here? reading the steel?

it's that visual thing we see that we are talking about, at least it's what I'm talking about when using a torch to quench with ,

you can't see this in the oven and putting in directly into the quench,
but the notes get you close to the right place and the timing
, is it close enough? yes for most..

I would not for a minute ever say don't use repeatable time tested notes but I do say for those that can see when the steel is ready
why not do it that way, if you can. it's fun for one thing seeing this..

this color thing is way off base BUT used a lot

.it's not color or a perception of a hue of the color, color of heat is a term trying to explain the correct time and temp to quench, which is a bad way to do so but used as a base point to start with. it's what the steel is doing around this collor, it's just a place to start looking for it.

it's no different than a prescribed carburetor setting on, say a chain saw, it will be close, but it still needs to be fine tuned after, the
base settings are just a setting so it will start and to be able to tune it. this is setting for a home owner is good enough for some guys,
many dealers use a tachometer for RPMs to do so after the base setting better,,, and good enough for still some dealers, a pre-determined RPM

others as myself used the ear to hear the way the gas is burning yes it can and is done this way by many of us
, then I check it with a tachometer to see where it is.
the tachometer is good but you still can fine tune it better because, no two engines are exactly the same they have their own personality if it can be described that way
the same with our steel we can get close with notes but are we fine tuning it? how would you have your chain saw tuned?

do you settle or go for optimum performance? ask a chain saw racer what he'd go for, you see there is a lot in this the world we don't know but it doesn't mean it's not there..
for those that don't see or can't see it
then time in a predetermined heat
is the way to go for sure,
same as directions on the paint can.

BTW I've been a Jonsered dealer for over 20 years and was a Stihl dealer
for over 20 years.also a dealer for Poulan Mac,Lawn-boy, with trade accounts with Briggs and Stratton and Tecumseh and more that I won't list. I've done the schools and the time tell me I don't know what I'm doing in that field,
my first knife was in 1974
it's just possible I don't know what I'm doing..because I'm not famous? who knows..
but remember books are also written by someone else and are written everyday with new stuff ,
if it's written it must be so right?, do stuff yourself to find out don't take my word for it. but always be open mined about what you don't or can't understand....
 
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