The Logic of Heat Treating Oils

Status
Not open for further replies.
Thanks again, Dan. You're explanations have finally allowed what I've been reading about torch-heating, colors, moving shadows etc. to gel in my mind, and to see the benefits of mastering this.

As a scientist by training, and by nature, I know I'll end up using ovens (and proper quenching oils :D ) in the future.

However, I want to get a better feel for what is happening in the steel (a picture is worth a thousand words, and a motion picture is worth 10000) and, as you say, you can't really see this when your knife is in the oven.

So, I'm going to try to get good at torch heating first, before going for the oven.

It's kinda like chemistry class. One day we had to make aspirin (acetasalacylic acid? or something) in the lab. It was hit an miss among the students (personally, I got a 120% yield, so I obviously did something wrong). We could have made aspirin more easily, with 100% accurate results, just by using more accurate and controlled commercial equipment, but we had to do it by hand, so we'd get a feel for what chemistry is all about. Given practice, we could have made the aspirin to be of the same quality as commercial aspirin using the hand methods, or so close the difference would be immesurable. By doing it by hand and eye, we learned a lot about the ingredients, the effects of the heating, even the rate of evaporation (using microscales). This kind of knowledge lends itself to experimenting and refining -- so does the controlled, commercial process, but not in such an obvious, in your face way.
 
Dan, so just where do I put the screwdriver to adjust the computer that controls the fuel injectors on a CART car so I can tune it by ear instead of balancing it by measuring head temps for each cylinder? :D :foot:

I'm just joking with you, Dan. :p There are different approaches that work for different people, and as I say frequently, "there's room for everyone". Different strokes. I would hope it didn't mean we couldn't be friends.... :) I've learned my lesson in that respect.
 
fitzo said:
Dan, so just where do I put the screwdriver to adjust the computer that controls the fuel injectors on a CART car so I can tune it by ear instead of balancing it by measuring head temps for each cylinder? :D :foot:

I'm just joking with you, Dan. :p There are different approaches that work, and as I say frequently, "there's room for everyone". Different strokes. I would hope it didn't mean we couldn't be friends.... :)
Click to expand...
hahaha
Mike
they wouldn't want you to get hurt with a screwdriver so they use chips now, or they might have outlawed them too..ever got bit by one? ouch :D

BTW though they use chips now they are tuneable with replacement chips:D
But with a bad O2 sensor the rest wouldn't matter anyway :p
but it's all about fuel air ratio and the conversion of Carbon monoxide to carbon dioxide and good ole H2O do to the EPA and that is good tech-no
at least for the air..

if having a say in something, causes one not to be a friend
one would need a reevaluation of themselves to why, am I right?;)

thanks Chant, an open mind is a learning mind..
that reminds me when working on cars , often when you have a lot of knowledge in autos today schools the test equipment and stuff, we at times over look the unobvious, a bad ground or a cracked vacuum hose.
and blame the computer or sensors, we need to look at the basics of what's there before the computer was. :cool:
 
We take ourselves very seriously at times. I try to remember once in awhile that I heard a comedienne on Saturday Night Live say "I want to be a knifemaker when I grow up," as she rolled her eyes. The real truth of the matter is that the vast majority in the world don't even know about us, let alone care. :) Not that that stops us or anything. :D

Have a great day, folks!
 
fitzo said:
We take ourselves very seriously at times. I try to remember once in awhile that I heard a comedienne on Saturday Night Live say "I want to be a knifemaker when I grow up," as she rolled her eyes. The real truth of the matter is that the vast majority in the world don't even know about us, let alone care. :) Not that that stops us or anything.

Have a great day, folks!
Click to expand...

Mike the up side to that is, she knew the term, knifemaker :thumbup: :D
and even said it on TV..now how many know about us or cares :confused: :D
 
Dan:
You have described the spirit of the functional knife maker very well. Some guys can tune a chain saw to book specks and wonder why it won't cut as well as another, they will send it back to the factory or buy new parts and try again, only to trade it in for another.

Then there is the man who knows the individual essence of the saw he is working on and can tune it the way it needs to be tuned and make her sing.

Same thing with horses, one man can take a good horse and get all that horse has to give, they come in at the end of the day having done a great job, they were a team all day. Another may have a horse of much greater potential but fail to get in tune with him and both come in at the end of the day exhausted and fed up with each other and acomplished much less.

When it comes to knives, one maker can understand performance and get the most out of that steel, while another depends on Rockwell alone a predictor of cut, chemistry as an indicator of the nature of the steel and some design that works against man and knife. The first knife will be a true partner, joining with man and task to make for good times, the other will simply be a knife, pretty maybe, but like the ladies in a beauty contest the winner may be far from a good mate.

The maker who has tested his knives doing what they were meant to do will have the honest understanding, the other will seek to know why his product does not work by reading a book. The first has found out why on the basis of performance and what more can we ask for?
 
Mr. Fowler, the part I don't understand is why would the two approaches be mutually exclusive instead of complementary and synergistic if combined? You yourself spoke of how helpful a furnace could be. You've written of the benefits of metallurgical analysis to further your understanding.

I'm missing something, and I'd desperately like to understand.
 
All our tools, be they furnaces, forges, torches, ovens, or books have their place, when blended together with knowledge,wisdom and goal oriented desire they work well toward the goal selected.

It is easy to get lost with all the advice available, or just as easy to put it all in perspective and take advantage of the stuff that works where it works. School taught me one thing, read, and know how to evaluate what you are reading.

Our science is directed to industry, our art is beauty or performace by choice, take the best science has to offer and blend it to our art and you can have the best of both worlds.

Speaking toward your comment about a furnace; fine grain is our goal, fine grain in a matrix is supreme. A furnace works in some stages, but when we have developed ultral fine grain it will grow at low temps, grain growth is a function of time and temp. if we limit time we limit growth. Long soaks can grow grain and negate all we have acomplished.

The goal is to keep everything in its place and know why. The only way we can find out why is be testing each blade.
 
Ed Fowler said:
.....The goal is to keep everything in its place and know why. The only way we can find out why is be testing each blade.
Click to expand...

Thank you for your reply. I couldn't agree more. :)

Have a good day, sir!
 
Ed Fowler said:
Our science is directed to industry, our art is beauty or performace by choice, take the best science has to offer and blend it to our art and you can have the best of both worlds.
Click to expand...
i like that now with all this info said and read it makes me wander what kind of increases can be had with high tec cpm steels ?
i need more $ so i can mess up some steel tring to find better ways:grumpy:
butch
 
Ed Fowler said:
...Speaking toward your comment about a furnace; fine grain is our goal, fine grain in a matrix is supreme. A furnace works in some stages, but when we have developed ultral fine grain it will grow at low temps, grain growth is a function of time and temp. if we limit time we limit growth. Long soaks can grow grain and negate all we have acomplished...
Click to expand...

:) Dang it! I knew I should have just quit reading this thread and been happy.

*EDIT- after mulling it over I am rewording this openign line in a way that may be diplomatic enough for me to be comfortable with stating the position. - Ed, your above statement just doesn’t seem to jive with the facts I have encountered or any of my experiences. * As the saying goes, we can all have our own opinions but we cannot have our own facts. As long as you do not exceed the temperature at which the carbides are in total solution, grain growth is not an issue. You can soak steel for hours on end if you are under this point with no grain growth. I always prefer to quote my own work instead of others, but considering the the steel used, I will refer to an experiment that Howard Clark once did with 52100 where he soaked it for for 5 hours with no grain enlargement just to prove that with controlled temps it could be done. Now I would imagine there is a time that diffusion would eventually catch up but it is beyond the scope of any reasonable soak.

I am sorry I do always try to show the respect due, but when I see bad facts I must be truthful as well. Finer grains do lower the coursening temperature but that is dealt with with temperature not time. Proper soaks are absolutely critical for dissolving some structures and if we let folks think contrary we are not relaying good information. Ovens do not grow grain if you control the temperature, and control is what ovens are all about. This is not a science versus art issue, with all due respect, it is just metallurgical fact.:)
 
I must say that I found my last post very difficult, but necesarry. I really am the type of person who would prefer to be in agreement with those around me and there was no malice at all in it despite how curt it may have appeared. I did want to mention that aside from the work of Howard's that I pointed to. I have been spending the last year experimenting with soak times in hypereutectoids to see what really is going on in our steel. I am often soaking as long as 12-15 minutes at 1500F. with spheroidal structures and I have yet to grow a single grain. Indeed I am finding how hard it really is to totally disolve carbides at 1500F. In O1 and 1095 I am often finding more residual carbides in the martensite than I thought possible. We can speculate and hope about carbides and grains but seeing them with my own eyes causes me to be ever increasingly slow to jump to any conclusions.
 
Kevin,

I am totally with you as far as fearing that a post, meant in good faith, will start a nasty misunderstanding. On the bright side, Ed seems to be a lot more understanding and willing to engage in productive debate than many others.

John
 
John Frankl said:
Kevin,

I am totally with you as far as fearing that a post, meant in good faith, will start a nasty misunderstanding. On the bright side, Ed seems to be a lot more understanding and willing to engage in productive debate than many others.

John
Click to expand...

I really did want to leave us all in agreement over quench oil, it preserved much more tranquility in my life, that is why when I saw it spinning off from that into so much subjective opinions, I wished to just bow out. But as of late I have seen a rather common misunderstanding of soak times resulting in the idea that they cause grain growth. This is not an isolated incident and we can only correct it if we clear up the misconceptions.

Ed, I am sure ultra fine grains are another fine thing that you are working with in the pursuit of the high performance blade and are more thatn willing to share, but I prefer to stay with the original topic that I felt a need to address- the idea that soak times grow grains. Far too often other issues easily divert us from an important point. Multiple cycling of hypereutectoids will produce all kinds if interesting effects but, by your own admission, keeping the temperature low is how you maintain them.

But let me not monopolize the podium here, as I have said you are not the only one to share this concern so if you have found a reason why the practice of soaking is counterproductive, help me understand. Please, remember however that I have a rather one track mind and have a hard time following some of the more poetic methods of explanation. My purpose was not to call you out in any way, but to give another side of a misunderstood issue so let me shut up and allow you to explain.
 
Kevin
not to cause friction or anything but you got me wondering now..
just a question because it seams related to what you just said can't happen so I need to know .
please tell me what happen to a blade I once left in the oven once for 2 hours, I totally forgot it,,it shoud have been out in 15min's

the steel was 154CM soaking at 1950 F
I air quenched it and then went through my regular temper and cryo'ing
this blade was a lot harder than normal and I had to retemper at a higher temp to get the hardness down more.it was hard you could tell just by the way it ground
.also
when I re-ground it and tried to finish in a mirror polish
it had white specks all though it's finish. it was so bad I refinished it in a
machine finish,

I always blamed it on the long soak time and grian growth, by what you say above
, I was wrong thinking this way, if so what happened to that blade, I've never had that problem since..and I never have soaked that long again,,
Thank you..

edited to change typo temp
 
Kevin: Please keep the language simple, I am just a poor broke down cowboy and don't know much about those big eutectoide kind of words. I firmly believe that if I can't speak in such manner that a 5th grader can understand, I fail to understand myself.
I highly resent your comment about subjective opinions, if you were aiming it at me concerning grain growth. I and we have invested a great deal of time and finances into developing imperical evaluation of what we have achieved and direction of where we seek to go. When we started a #10 grain was only theoritical in 52100, we reached that, and have now exceeded what was the theoritical limit.
There is nothing subjective about grain growth resulting from variables such as temperature and time. The finer the grain, the lower temperature at which it will grow. Low temp, slow temperature change, high percentage reduction by forging and careful forging all come together if done right.


While trying to preserve a #14 grain may not be a concern to most bladesmiths, I mention what we have learned in the hopes it may one day save another bladesmith from making the mistakes I have made.

I did not mean to upset you, but do not feel that either of us is the guardian of truth for all.
 
thanks Mike it was 1950:foot: :o
but I do 15 min after it has reach temp.I've alway done it 15
TKS does also.
it's where I got my chart from..
 
Dan Gray said:
thanks Mike it was 1950:foot: :o
but I do 15 min after it has reach temp.I've alway done it 15
TKS does also.
it's where I got my chart from..
Click to expand...

Times differ from person to person, of course. I was more worried about the temp. I time it 20 minutes after 1950 because it spends about 10 minutes to get there from 1900 in my furnace.

I was trying to save any embarassment of someone noticing, "Well, at 1850, maybe you finally got some hard spots after 2 hours!" :D :D (That's a joke, that's a joke, that's a joke. :eek:)
 
Status
Not open for further replies.
Back
Top