Tripple quench, once and for all. Maybe

[Mark Williams]

Trippple quenches are to help refine the grain correct? A more refined grain structure is our goal is it not? Then I guess it boils down to this. Does a trippple quench refine the grain more than a single? If the answer is yes then I dont see the point in beating this poor horse to death.

[DaQo'tah Forge]

Opinions on this topic vary.

But I would welcome some data that is produced by the people that manufacture steel in this area.
To triple quench or not is a question that I don't think the average knife maker, working on his own can answer 100%. All the tests that a normal knife maker can run on his own blades are subject to a wide variety of uncertainties.

Cutting tests are hard to reproduce from one single cut to the next, let alone from one blade to another.
HRC hardness is an interesting thing to know, but it alone is not everything.

Im a very new knife maker and I have no plans at all to actually making a living on what is just a little hobby of mine of making a knife in my free time. But when I started out in this sport I did the triple heat treatments that everyone talked about here on the forum all the time.

I had no reason not to triple quench, as people that make greatest knives all seemed to support the idea.

Then a saw a few posters start to question the merits of the triple quench. I also noticed that there seems to be a complete lack of support in the scientific data given us by the steel manufactures that can be used to support triple heat treatments.

When I ran a few questions by my brothers here on the forum I was told that the best thing to do is for me to begin my own testing of blades head-to-head and see for myself if a triple quench improved my own blades. This is because everyone has a slightly different style so my system is always going to show slightly different results that others.

Well I have run a few tests and for the life of me, I cannot find any difference between one of my single quenched blades and a triple.

Also, this last winter I talked to a welding inspector about some of the problems both he and I have in common with the heat treatment of steel Turns out that fresh after welding steel , the welder faces many of the same problems I do as a knife maker at getting rid of the stress within the steel.

I was given a teaching video about heat treating steel from this welding inspector, and learn a few things about hot steel that guys like METE have been talking about since I first logged onto Blade Forums.

I believe this video was produced either by the steel manufacturer, or by a company that has something to do with guaranteeing the quality of their welders. The company clearly has a huge money investment in showing the people that are meant to watch this video how to properly deal with the many different problems that can be caused by improper welds.
I took what I was seeing as very serious.
From the video, and from a long conversation I had with the welding inspector about the possible merits of multiple heat treatments, I have been unable to find the type of science-backed support for continuing the triple quench that I was looking for.

However... I still am VERY interested in this search for answers.

Knife making is an art, and as an artist I think that I should not allow science to lead my craft and my exploration of my blades, however I should be able to point to science as a way to support the path that I have walked too

[mete]

Go all the way and call it trippple quench instead of triple. LOL Theoretically it is to refine grain size.Under carefully controlled (laboratory ) conditions it can be done but the average 'smith can't. Bladesmiths seem to be hung up on threes - triple normalize,triple quench, triple temper, triple cryo.It's like the three monkees - hear no evil, see no evil, speak no evil. Did you ever ask why there doesn't seem to be any knife that is triple anything ?

[Mark Williams]

Well crap mete, I'm dissapointed . i was expecting some $20 words with names like helical, monolithic, rudamentory, particulate. Just calling the trippple guys stupid is too easy.

[DaQo'tah Forge]

The DaQo'tah Tripled Heat-Treatment System.

I start off aiming for a one-time heating and single quenching

I heat the blade and quench in oil, unfortunately I have neglected to pre-heat my quenching oil, and so this whole attempt is shot.

I try that again.

I heat the blade and quench the blade in the now properly pre-heated Texaco type A quenching oil.

However I am soon consumed with self-doubt.
Did I get the blade heated evenly? Did I over heat the cutting edge? Was too much of the tang heated in the fire? Did I count to 5 or 9 when I first dipped the point? While I have been thinking of such questions, have I lost count of what Im doing right now? Did I just dip the cutting edge too long in the oil?

Better try that one more time.

I heat the blade again, and quench in the oil. And while I work, force myself to think about absolutely nothing!

Yes, the fact is,
The Third times the Charm!

[jhiggins]

I think the triple-this-and-that is myth like Mete says. An arrested state of grain structure within the steel is done during the quench. No matter how many times we bring a blade up to non-magnetic and quench it, the results are the same. This does for the tripling of tempering and everything else. Do professional heat-treaters have time to triple everything? No.

Its basically a byproduct of human frailty. We think we are being cautious, or more to the point - thorough, by triple-doing everything. Some will swear by this, though.

[peter nap]

OK Mark...here's the REAL ANSWER.

Two fellows are looking for a really good hunting knife. These are real people, from the south and experienced in using a knife! :footinmou

Mete and I have tables next to each other. On Mete's table is a beautiful knife with a sign that says. 4" Hunter. bright plated, never rust steel and helical, monolithic, rudamentory, particulate trippple heat treated.

On my table I have a hunter made from 5160 and darked etched with a walnut handle. My sign says:
4" Hunter. Made from a car spring and triple quenched in Crisco!


The two customers look at Metes table and say to each other, what in the hell does that mean. The other says "I think it's a foreign language, must be made in China"

They go to my table and say, "That thing will cut like Hell, I'll take her"

That Mark, is the reason for triple quench!

PS...they also cut better if you triple quench them!

[NickWheeler]

Relying on a notion that simply advertising as triple quenched will sell you a knife is NOT something I would recommend to anyone.

"Billy Bob and Jerry Lee" would be much more impressed if you advertise how it was made, AND YOU can back it up and explain it. I can't tell you how many times I've overheard newer makers at hammer-ins and shows telling people, "Yes, this thing cuts like cracy cuz it's triple quenched!!!" Then someone asks them what that does and why it made it cut any differently than if not..."Uh, I don't know, but Ed Fowlder does it!"

Don't get me wrong, I am NOT barking at Ed here....that's just the reply.

They really don't have a clue what went on..other than: they got it hot, stuck it in oil and somehow it's harder now than it was before.

Now if you tell them your feelings on heat-treating, tell them they're based on scientific data, and real-world application and experience from your work AND testing your work...then that's something to help you sell a quality knife.

Since the originial question was about the triple thing itself.

Personally, IMVHO, etc.... I feel the guys doing it are using a heat-source that does not allow them to get the steel into solution, soak it there for a short time, and quench. So they have to go back and do it two more times to try and get their blade converted into a state of martensite.

But before I go on and on...no-one is ever going to completely agree on this topic....so I won't waste my breath.

Nick

[mete]

Well if you want me to be technical, it comes down to the mistaken belief that the triple quench forms only straight dislocations therefore assuring a straight blade. Single quench forms both straight and screw dislocations but if your forging is proper the screw dislocatons will be aligned with the blade and it won't be warped.

[rlinger]

My question has been if I do it correctly the first time how is taking the steel back to solution and quenching again going to help. Am I not erasing the effects or state of the first quench by doing it all over again(?).

RL

[Jason Magruder]

I don't think that triple quenching does much to help the blade, but I always have believed in triple normalizing. After grinding or forging I normalize then straighten then normalize. Usually it still needs a little work so I straighten it again and normalize again. I've never had a blade warp since I started doing this.
I think triple quenching came about as a result of not getting it right the first time. And if I can't get it right the first time everytime then I don't trust it enough to sell. That's why I have tried to quit using carbon steels until I can get a salt pot going. I say "tried" because I have this bad habit of welding different steels together and making knives out of it. I just can't help myself.

[peter nap]

Geeze Nick . I didn't expect anyone to take that post seriously! I was responding to Marks response to Mete and making fun of some of the technical information that both Mete and Rodger post that goes right over my head.

I didn't mention this because most of had already been said but for the most part I agree with Mete and everyone else that the triple quench does not help. It does work for me because I do not get a complete quench the first time and the third is just insurance.

The reason I do not get a complete quench is because I quench in Crisco. First quench is in solid Crisco, Second in the warm liquid from quench 1 and the third in hot Crisco from numbers 1 and two.

It works for me and I don't plan to change until I find something that I like better. I triple temper also for the same reason. It seems to work and sure doesn't hurt anything. I also freeze them because I have done it for many years and it doesn't hurt anything.

Contrary to other posts I have made, I do not only forge during thunderstorms or quench as the lightning strikes. Not on purpose anyway.

The other post was not malicious, nor was it intended to take away from Metes technical prowess or advocate the triple quenched car spring advertising method of selling knives!

[Kevin R. Cashen]

Originally Posted by Jason Magruder

I don't think that triple quenching does much to help the blade, but I always have believed in triple normalizing. After grinding or forging I normalize then straighten then normalize. Usually it still needs a little work so I straighten it again and normalize again. I've never had a blade warp since I started doing this.
I think triple quenching came about as a result of not getting it right the first time. And if I can't get it right the first time everytime then I don't trust it enough to sell. That's why I have tried to quit using carbon steels until I can get a salt pot going. I say "tried" because I have this bad habit of welding different steels together and making knives out of it. I just can't help myself.

I think you have made some of the best points in your post Jason, I wholeheartedly concurr. If done properly, multiple heats to just above Ac1 will refine grain, it is just when one preffers to do it. At one point it can be incorporated quite nicely, at another it could cause more grief than help. I use 3 or 4 cycles not because 3 is a magic number but because there is a point of diminishing returns. 10 or a dozen normalizations is about half a dozen wasted heats. And lets never forget that too fine of a grain can be VERY problematic in simple steels if you want to reach full hardness.

Here is what I do and why- At the end of forging if I think I did a real good job at controlling temps, I will then heat the blade to Acm (completely non-magnetic, for simplicity sake) and let it air cool. The critical part is to get everything the SAME temperature, I am not so concerned with the exact temp as I am with even temp. This is to get the grain size as even as possible regardless of that size.

The next heats will be slightly lower, since all I want is to nucleate new fine grains within the courser framework of the previous ones. With a steel like 1095 the last heats could be just enough to start the spheroidizing process so there will be no need for heavy and involved annealing operations. With my L6 and O1 there will be residual hardening that will assist in the spheroidizing process to come. I use spheroidizing because it leaves the grain structure alone while softening the steel completely. If one goes for a traditional lammelar anneal after all the cycling, they could undo much of what they have accomplished in grain size reduction.

If I have been doing some outrageous heating (welding) on the steel, I am not above throwing a quench in between two of the air cools to drastically reduce grain size by using the massive stress of the martensite to help things along.

I do all of these things right after I forge, before I even grind it. That way I can grind away any decarb, straighten any warps and have complete control over the internal structure before the critical heat treat. I also use a heat source that will alow me to achieve a completely even heat all at once, otherwise I would be wasting my time.



No trying to step on anybody, I am just saying what I do and why I do it.

[Terry_Dodson]

Mr Cashen you said "With a steel like 1095 the last heats could be just enough to start the spheroidizing process so there will be no need for heavy and involved annealing operations." about what temps are these at? i am trying to learn to use my temp meter in my forge to make sure i dont overheat things. I am using 1080 and 1095 steel.

oh and Nick my name is Terry Lee and i am in SC

[mete]

Steels with carbon content at or above the eutectoid (1080) are difficult to machine if the structure is pearlite .Therefore they are treated to a spheroidize anneal condition where the carbides form spheres in a matrix of ferrite ( like chunky peanut butter). This is done by heating to approximately 1250-1300F and held for some time at temperature . This is spheroidize anneal or subcritical anneal.

[Kevin R. Cashen]

What mete said!

[Terry_Dodson]

mete so is that different from normalizing? and if it is how long do you need to hold at temp? i have been normalizing at 850 celcius ( my cheapy temp meter only reads celcius)

[mete]

850 C =1562 F, that would be the metallurgists normalize ( 100 F above critical , air cool ) which yields pearlite. For the spherodized carbides to form in the spherodize anneal it takes time which I am going to have to research .

[Sethhoward]

For simple steel "AT TEMP" might just be a couple of minutes, while something more complex like L6 is normally a few hours for spherodize vs. a minute or less for normalizing unless I am totally off.


Seth
www.sethhowardknives.com

[Lynn]

Here we go again! I thought someone had done tests and found that holding at the critical temp was the reason for the triple. I don't have the equipment or the expertese to do a proper test so I depend on others.
Not that I don't think for myself. I took a class with a famous maker and was told to bring the steel up to critical as quickly as possible. When I questioned that I was told that he was a rocket scientist and (another maker I quoted) wasn't so I should take his word for it. I still try to bring up slow because it makes sense to me that the atoms (molicules?) need the time to react.
Terry Lee in SC. Can you tell me where to find the "cheapy temp meter?"
Lynn