Jump to content

Recommended Posts

I'm on about my 9th reading of it....and still mulling a lot of it over in my brain

:D

He's been a bad influence, I'm into my third ASM course now.

I'm getting edumacated...

 

:wacko:

 

The ASM has courses? Are these online? Available only to members? Inquiring minds want to know! :D

Link to post
Share on other sites

Don't use the word 'packing' it's a MYTH !! As you drop below the austenite range you get either pearlite [slow cool] or martensite [fast cool]. Sam , you need to do more reading !!

 

Ya know, I've been biting my tongue over this all morning, and I have to admit, I'm pretty hot about it presently. But I'll try to stay calm.

 

I was taught packing by a guy when I was very young. I still do it, I still believe in the results.

What's changed in the last 30 years of making knives, for me, is my understanding of how some things work, and how they don't work.

 

The olde guys thought that packing mechanically, physically reduced grain... because thats the results they SAW as opposed to other methods. Yes, the way it happened was misunderstood, yeah, to say that is not how it works is entirely correct.

But, when the steels used allows, maintaining failry low heats, from just around critical to just into the blacks, through the reds, will in fact either reduce grain size, or at least keep it small, because it all serves as multiple normallizing cycles. Which DOES in fact work.

 

So say it's missunderstood, or incorrectly percieved, whatever.

But I find the fact that so many jump on it so quick and call it a "myth" or "false" is highly insulting, and frankly, kinda ignorant.

My teacher died before I had a chance to go back and share any of the things I learned over the years, and I will always have a great deal of sadness regarding that.

But I certainly wouldn't have gone back and said " hey, you're wrong, that's just a myth"

He wasn't wrong, he just missunderstood the actuall mechanics of the effect he was seeing.

I could now point that out to him and show him, physically, by cycling some stuff and breaking it, having a fun afternoon in front of the forge and drinking a couple of beers. And still thanking him for everything that he had shown me.

 

Know what I think is a "myth"?

That learning and knowing are the same things.

Link to post
Share on other sites

My purpose here is to educate and destroy myths. When you hammer metal you don't make grains smaller you just distort them . You don't 'pack' the atoms closer you actually increase the volume since you create dislocations. Engineers are sometimes criticized for being very picky about terminology But I'd like all of you to understand exactly what the process is and use the right terms so everyone understands.

Link to post
Share on other sites

That's fine, i understand that, but I can't see why an explanation can't be included, instead of just saying "it's a myth".

 

It's NOT a myth, it's just entirely missunderstood, and in explaining that, it would shed a great deal of light on normallizing and the many forms that the process can take.

 

Maybe some of the egineers could learn OUR terminology for once eh?

Who do you suppose came first, blacksmiths, or engineers?

Link to post
Share on other sites

I re-read what you said, and it leaves me thinking you didn't even read my post through.

 

I know we can't physically "pack" grains, or "squash atoms".... that wasn't my point.

Edited by RHGraham
Link to post
Share on other sites

Please guys, I value the posts of both of you WAY too much for this to become heated, or adversarial.

 

You're both saying the same thing, just expressing it using different 'languages'! I'll admit that it's an awful lot for the engineering community to expect us to gain fluency in their 'language', but I also know that I have a much better understanding of what's happening because I'm trying to learn it!

 

Everyone needs to remember that we frequent these forms to exchange information. Sometimes language barriers exist, but we can't allow them to denigrate our discussions!

Link to post
Share on other sites

Fine, I took the "offensive" part out, don't want to hurt anybodies feelings, that would be such a terrible thing.

 

For the record, I'm EXTREMELY insulted by the way "mete" states his case sometimes, and I don't believe what he does is educating, it's just "telling", the way he believes it is, on any subject.

 

And if somebody is going to proclaim themselves as the educator of the board, they should have thier real name on thier profiles. For that matter, i pushed before for real names period, and still feel that way now.

 

"Mete" makes statements of rigid fact that I don't believe he's backed up by trying things relating in his own shop, if he has one.

 

He also didn't bother to read my post through and understand what I was trying to say, just took on the usual superior attitude, and used a berating method to "educate" me about atoms. And still stated it as "myth", out-an-out, and as far as I'm concerned, did it in a very condecending manner.

Nobody else is willing to call him on his atitude, I am. Oh well.

 

In any case, ya'll can work it out. I don't think this particular style of "educating" is worth a pinch of shit personally. It always seems to be ridgidly one way, out of the book, with absolutely no attempt to find out if anybody else's expirience is valid, or even worth considering. IF he wants some respect, he should try giving some.

Link to post
Share on other sites

1

Edited by Robert Kobayashi
Link to post
Share on other sites

Mete,

 

I might be wrong but I don't think that anyone has even seen an atom.

 

 

Hey! I've seen an atom! This reminded me of an article I read a while ago, and I found it here:

 

IBM Logo made of atoms

 

 

Pretty cool, eh?

 

 

I see your point, Mr. Graham... although I'm not sure if mete means to come off sounding as condescending as his sometimes does. There are lots of instances where certain personalities drive me completely nuts on these forums, but I need to be on them -- if for no other reason than to temper my own views with those of others.

 

BTW, did you mean that chapter in Verhoeven's text titled "Control of Grain Size by Heat Treatment and Forging"? :blink:

D'oh! I swear, I did read it... I just somehow managed to forget that incredibly important part! Man, am I a sad example...

Link to post
Share on other sites

1

Edited by Robert Kobayashi
Link to post
Share on other sites

1

Edited by Robert Kobayashi
Link to post
Share on other sites

...Engineers are sometimes criticized for being very picky about terminology But I'd like all of you to understand exactly what the process is and use the right terms so everyone understands.

 

This is an interesting and useful thread, perhaps a bit overheated. Here are my thoughts:

 

In general I agree that using the correct terminology improves communication. However, for someone with a different background the terms don't necessarily convey the same thing. For example:

What's plasma?

1) kind of color TV

2) blood plasma

3) hot ionized gas (in stars, fusion reactors, & plasma cutting torches)

All are "correct" - within a particular discipline...

No one wants to be treated with disrespect, or talked down to...Writing for a broad audience with a range of backgrounds is tricky. Invariably not technical enough for some, and too technical for others...

 

I know some bladesmiths that prefer to debunk the atom packing & grain refining by forging aspect of "edge packing" - but then proceed to point out that the heat treatment is what is pertinent, and works...

 

When I go out to my shop my tendancy is to put away the engineeering aspect of my background and be sure what's going on is safe, and make an effort to make what I want. Hands on is very fun, useful - & frequently humbling!

 

Cheers,

 

Byron

 

...Maybe some of the egineers could learn OUR terminology for once eh?

Who do you suppose came first, blacksmiths, or engineers?

 

Some of us are trying...

 

Byron

Link to post
Share on other sites

Mete,

 

But much of science is based on things that are not thoroughly empirical in their nature.

 

All throughout my (continuing) education these seemingly little details (like the validity of atomic structure) kind of bugged me.

 

We as engineers are pretty detailed in our perusal of many things. But take other things at their face value.

RK

 

This thread has begun to slide off original topic, and this may not help, but a couple of points:

 

It is amazing how well the theoriticians can - sometimes - predict things later borne out by experiment.

 

Physicists don't generally understand materials from a met. or mechanical enginering perspective. Engineers don't generally understand particle physics...

Science is not a monolith of knowledge, but a continuous revision of theories & models, scrapping of theories & models...

 

Back to original topic:

Anybody else have interesting info to share on triple hardening?

Link to post
Share on other sites

From a practical standpoint my experience with triple quenching of low alloy steel has been very positive. I work pretty much exclusively with 5160 and O1 and a few years ago did some very rigorous testing with different heat treat scenareos. My experience with these steels is that multiple quenches (minus the wait period someone was descibing earlier...) did indeed reduce grain size. It was visible in broken cross sections with a magnifying glass and also in the lab.

 

I had a buddy at the time who worked in the testing department of a local manufacturing plant and had access to all kinds of goodies...microscopes, chemical analysis, stress testing. :) I even borrowed a heat treat oven (Paragon) with digital controls for a few weeks to play with.

 

My experience was that the multiple quench routine works. Science says it works, experience says it works. Now, that it works better than multiple normalizing sequences I can't relate. I did not find that I could tell the difference by eye or by break tests but as I remember the samples I had tested had slightly smaller grain and performed slightly better after multiple quenches. My *opinion* is that multiple and careful normalization cycles is probably 90% as effective *on the steels I played with* but most of my testing was subjective and empirical. The lab tests pretty much showed what I thought they'd show.

 

In the early days (mostly because Howard showed me stuff that blasted my mind...) I tested up pretty much an entire 22' bar of 5160. Two evenings a week for almost a year all I did was heat treat and then break stuff and really scrutinized the grain structure, relative toughness/hardness and abrasion resistance.

 

Small grain is good. Normalizing in multiple sessions makes it smaller. Hardening it multiple times works as well, maybe better in my subjective and empirical tests as verified by the lab tests. Could I tell the difference in a knife? No, I couldn't. But I'm sure there are guys who could find it.

 

The best way to decide if you should be doing this is to read everything you can find and then go to the shop and see if it proves out for you. Reading/asking is learning. To do it is to know it....you don't know till you have done it and I really have a better grasp for having spent all the time and money to break a bunch of stuff.

 

Brian

Link to post
Share on other sites

Triple hardeneing, as in heating and quenching multiple times at the end, I don't think is ideal, but it can produce a blade with quite fine grain in some steels and again, although I'd not do it that way, I can't see any reason why it nessecarily shouldn't be done. IF it works, and the blades are tested, and the maker/customers are happy with it, I can't see any good reason to criticize it.

 

Using quenches at the end of a normallization heat I think is a better way, particularly if a smith is set-up with simple gear, ie, only his forge for heating without temp controlls. It can be really hard to hit specific temps out of an open fire, which can make a situation where a smith might not be able to produce a nice fine grain consistantly just from a "standard" normallization routine where you heat to what you hope is a little above critical and air cool.

 

When I heat-treat a 1095 blade out of my open forge, I warm the fire up so the lining "looks" like it's around 1500F or so and preheat it good. Then I turn back the gas some, and start the first heat. The blade will pretty much go to the 1500F mark the first time, a soak, then a quench in oil. It's a flash quench, I don't hold it for a long time, or worry about getting it to MF, just get it into the blacks quick, then right back into the fire. By now the fire has dumped some temp.

Second heat and soak, and quench again, another flash quench, and back to the fire. Usually that time has been closer to 1450f or so. On the last soak, I can usually hit it right around 1400 and I can see the edge flare as it comes up to temp. I quench again, but this time I hold it till it's 120-140F.

Again, right back into the fire and hold it for a good long soak in the reds, Just around 1200-1250F, for a "soft temper", or "soft draw".

The blade will be very fine grained, very easy to work with files, drills, etc, and set-up wonderfully to heat-treat later.

 

It's all by eye, in an open fire, all low-tech. The quenches can help produce a finer grain, in a situation where your temp controll may not be ideal otherwise. Not everybody has access to digital-controlled equiptment or salt baths, but with some steels, neither do you have to.

 

I use an infrared pyrometer sometimes to practice, check out the forge, check out my eye.

More often I'll "tune myself up" by cycling a piece a few times and simply seeing how "cold" I can go and still have the blade recallece when it comes down. Using the pyro to confirm I can very regularly hit 1400-1425F when I'm really trying hard. For low-alloy steels like the 41XX series, O-1, L-6, and stuff like that, I usually only do two norm/quench cycles, and the "range" of norm temps is run up a little higher.

 

In my expirience you don't have to worry about hardenability with 1095 or W-1, or any of the other simple steels, till you pass four or five of those norm/quench cycles. Other steels like W-2 or 1086M three is right on the edge of too much, a lot of care is needed there.

 

In steels like L-6 or O-1, norm cycles with quenches and the "soft draw" in the reds afterwards are about the only really good way to get the stuff soft enough to drill and cut and file in a simple shop set-up, and a fantastic way to prepare it for the hardening IMO. Otherwise, a process anneal is needed. All a heat and air-cool will do to L-6 is make it coarse and hard.

 

If a blade gets so fine it won't harden, which can happen, the way to reset it is to run it up really hot, 1700-1800F, a long soak is not required, and flash quench it in oil, then immediately go back into your normallization routine. It'll fix it.

 

And not one bit of this has to be taken at face value, so don't. Try it, break some samples, see if it works for you.

 

There, how's that?

Edited by RHGraham
Link to post
Share on other sites

1

Edited by Robert Kobayashi
Link to post
Share on other sites
  • 2 weeks later...
  • 1 month later...

Create an account or sign in to comment

You need to be a member in order to leave a comment

Create an account

Sign up for a new account in our community. It's easy!

Register a new account

Sign in

Already have an account? Sign in here.

Sign In Now
×
×
  • Create New...