Is forging still worth it?

[Keith Montgomery]

Forging does not do that.

Many articles that I have read lately report findings that differ with that assertion. It would be very interesting to see a scientifically objective test set up to show which is correct. Cliff, if you can direct me to some research (not anecdotal), I would love to be able to learn more.

 

[Josh Muller]

man... im having to reference a dictionary a lot for that post.

erased a paragraph there because i dont think its quite right now that ive read, defined, and restated what cliff said... took me a good 20 minutes to fully grasp though

so, a few definitions to help those who know as much or less then i do on the subject

Forging does not do that. Grain refinement can only happen during the heat treatment cycle, and any working operation such as rolling or anything which stresses the steel either previous to, or during the martensite transformation

martensite: is the hardest of the transformation products of austenite and is formed only on cooling below a certain temperature known as the m(A) temperature (about 400-600 for carbon steels). cooling to this temperature must be sufficiently rapid to prevent austenite from transforming to softer constiuents at higher temperatures

transformation: 3 a (1) : the operation of changing (as by rotation or mapping) one configuration or expression into another in accordance with a mathematical rule; especially : a change of variables or coordinates in which a function of new variables or coordinates is substituted for each original variable or coordinate (2) : the formula that effects a transformation b : FUNCTION 5a c : an operation that converts (as by insertion, deletion, or permutation) one grammatical string (as a sentence) into another; also : a formal statement of such an operation

constituents: 3 : an essential part : COMPONENT, ELEMENT
4 : a structural unit of a definable syntactic, semantic, or phonological category that consists of one or more linguistic elements (as words, morphemes, or features) and that can occur as a component of a larger construction

austenite: is the non-magnetic form of iron and has the power to disolve carbon and aloying ellements. normally formed at the upper transformation range (2500 degrees+ (?))

after the soak will induce a finer grain.

The grain refinement is due to an increase in dislocation

dislocation: b : a discontinuity in the otherwise normal lattice structure of a crystal c : disruption of an established order

density

density: 2 : the quantity per unit volume, unit area, or unit length: as a : the mass of a substance per unit volume b : the distribution of a quantity (as mass, electricity, or energy) per unit usually of space (as length, area, or volume) c : the average number of individuals or units per space unit <a population density of 500 per square mile> <a housing density of 10 houses per acre>

in the stressed steel which leads to an increase in nucleation

nucleation: 2 : a central point, group, or mass about which gathering, concentration, or accretion takes place: c : a characteristic and stable complex of atoms or groups in a molecule; especially : RING <the naphthalene nucleus> d :

cites during the crystal transformation

crystalline - comprised of a geometric lattice work in the atomic structure

and therefore a smaller grain as the boundries intersect with each other faster as there are more of them and thus they have less chance to grow.

SO.... now that i understand how the words relate to the sentence, im still a little lost on some of the sentences, specifically:

"and any working operation such as rolling or anything which stresses the steel either previous to, or during the martensite transformation after the soak will induce a finer grain."

i dont mean to be pedantic or to be petty in trying to prove a point or anything like that, its just that that sentence appears to state that the act of forging, or stressing the steel by use of a hammer, iether during the martensite transformation (400-600) or before that period (when its above 600 degrees wich i assume also includes the forging range) will have the effect of refining the grain structure. that appears to state that forging does in fact refine grain structure.

"The grain refinement is due to an increase in dislocation density in the stressed steel which leads to an increase in nucleation cites during the crystal transformation and therefore a smaller grain as the boundries intersect with each other faster as there are more of them and thus they have less chance to grow. "

i think i understand this... but i would have a difficult time trying to explain it to some one... the larger the crystalline latice work (set of box's that the atoms are aranged in creating a patter) is allowed to be during the cooling stage, the larger the grains can become, because they can build themselves up on the large already present latice work. if the latice work is disrupted creating not so much of a chaotic arrangements of metals (like in glass metals), but a set of disconected latice works, the grain size is only able to build itself as large as the available latice works. by breaking them up as much as possible across the length of the blade/edge (dislocation density), you force the grain size that forms upon colling to stay as small as possible.


right

 

[Megalobyte]

There actually is an advantage to forging. It is in refinement of the grain structure of the steel. What is done when steel sheets/rolls are produced at the mill does not refine the grain structure like forging does.

Edge packing and increased density is a myth. Steel does not compress when hammered, it spreads out.

Yup, I remember Steve Schwartzer saying this in an issue of Blade a while back.

I like forging for the simple reason that it is the original, ancient art of making a knife and I appreciate the history, skill and work that goes into it, stock removal, while it may produce a very good blade, seems a little sterile to me. In a high-tech world, where everything is pretty much done by unthinking machines, I really appreciate the concept of a smith hammering away on a molten piece of steel, forging it to shape in a fire, something ancient and primal in it to me.

Maybe I'm just nostalgic and look back to simpler times, even though I wasn't born yet, and like it or not, was born into the age of mass, high technology. I'm rebelling.

 

[Steven Roos]

Maybe I'm just nostalgic and look back to simpler times, even though I wasn't born yet, and like it or not, was born into the age of mass, high technology. I'm rebelling.

Try being a 20 year old Bladesmith. It's weird! lol!

The whole argument about grain refinement is hard to prove either way. If we want to argue, let's get Ed Fowler in here and start something serious! :footinmou

Honestly though, it is mainly personal preference, because I'd bet a large majority of hand forged knives are out there as collector's pieces, not users.

 

[Satrang]

The correct statement regarding grain refinement is that under certain forging parameters you can refine the grain structure. The dislocation comments are correct as these are the initiation sites for grain growth. The grain growth happens when the steel is heated above the austenite range. The key to refining the grains is to work the steel below the range, heat to above the range start to grow grains then work the material again and cycle back through the process. Where the process goes wrong is steel that is heated and held too long in the austenite range. The grains will grow too long and any refinement is lost or even grown beyond the starting point.

Forging will create the necessary dislocations but it must be matched with the correct thermal cycling.

 

[Keith Montgomery]

Not mentioned before, but another advantage of forging is that there is far less wasted steel, e.g. a 10 inch flat ground blade 1.6 inches wide, like the one below:

To make the above blade by the stock removal method you require a piece of steel a bit over 10 inches long by 1.6 inches wide. You then grind away everything that isn't finished blade. You need a much smaller piece of steel to make the same blade by forging, because the bladesmith moves the steel until close to the final shape and then only grinds away a small amount of steel to get to the final shape. I know of quite a few bladesmiths that forge to better than 95%, and some that regularly forge to better than 98% of the finished shape. This also produces much less wear and tear on belts and grinding wheels and shop machines. Of course, there is far more wear and tear on the human body.

This is something that was pointed out to me by a very knowledgeable member of this forum. The advantage that forging provides is is most evident in blades such as khukri, kris and many of the other a Asian/Oriental knives/swords. Think about how much steel you would have to grind away to make a khukri blade.

 

[Alpha Knife Supply]

Has anyone here actually watched or participated in grain refinement testing? If you get an opportunity I highly recommend attending.

I've watched it several times on different occasions and it is amazing. The steels tested were O1, 1084 and 52100. None of the steels were hit with a hammer. The grain was refined by thermal cycling only. Everyone examined the grain at the beginning and end of the tests. Bars of steel were overheated then quenched and broken to examine the grain. The grain was very course. The same bar was then heated to critical and slowly air cooled several times. It was then heated to critical, quenched and broken to see the grain which was very fine. Mastersmith Bob Kramer performed the test on 52100. When everyone was looking at the grain he said, "Hitting the steel with a hammer would do nothing to further refine the grain."

Cliff, a better test would be to have a maker make two knives, one forged and one stock removal from the same bar of steel. The maker would also perform the same heat treat process on each knife. If the two knives are heat treated the same, the variable would be how the knife was made.

For example, lots of bladesmiths are triple quenching their knives because they say it maximizes the amount of converted martensite. The result is a tougher and better knife. The amount of martensite gained may be outweighed by the grain refinement because of the increased thermal cycles. This is just my opinion.

Why does it matter which way the grain goes? The reason I hear all the time is "a forged crankshaft is better than cast" referring to automobile engines. "The grain of the forged crankshaft makes it stronger". In high performance engines the crankshafts are cut, not forged, from billets of steel.

Don't forget to have the horn of the anvil pointing toward magnetic north before forging. It helps align the grain of the blades being forged.

Quenching . . . . . . . . . . sacrificial virgins . . . . . . . . . . chicken blood . . . . . . . . . . full moon . . . . . . . . . .

BTW, all steels including stainless are forged.

 

[Alpha Knife Supply]

Not mentioned before, but another advantage of forging is that there is far less wasted steel, e.g. a 10 inch flat ground blade 1.6 inches wide, like the one below . . . To make the above blade by the stock removal method you require a piece of steel a bit over 10 inches long by 1.6 inches wide. You then grind away everything that isn't finished blade.

Keith, I have to call BS on this statement. A custom knifemaker who does this is not working very smart. The knifemaker will buy a longer piece of steel and overlap the tips making two knives, or make a smaller knife out of the triangular shaped piece. Grinding away that much steel is a waste to time, belts, steel which equals money.

Think about how much steel you would have to grind away to make a khukri blade.

Why not nest them on a big sheet and waterjet cut them? Waste would be minimal, probably less than forging.

What about the wasted steel that turns to scale in the forging process? Have you ever ground forging scale? It makes heat treated S30V seem easy.

Don't misunderstand me, I love forged knives. I also love stock removal knives. The engineer in me prevent me from falling for the "Mysteries of Forging". Forging steel is science and physics. Anyone who defines their process by defying science or physics doesn't understand what they are doing.

 

[Cliff Stamp]

Many articles that I have read lately report findings that differ with that assertion.

Then you have read a lot of incorrect articles. I have posted actual journal articles on this before when the same incorrect presuppositions were brought forth. Not something published in Blade but in an actual peer reviewed materials journal. The properties I referenced are all well known based on statistical laws mainly. If they were wrong then an awful lot of science would need to be rewritten. Debating them shows a serious lack of basic materials science.

by breaking them up as much as possible across the length of the blade/edge (dislocation density), you force the grain size that forms upon colling to stay as small as possible.

Exactly right and note than any stress does this, including rolling. It is also optimal to do it *during* the heat treatment, not before it. Note as well that not all properties are actually maximized by grain refinement anyway, and then you have other comparisons such as differences in steel thus hammer forging limits materials just like stock removal, plus you have stock removal makers using full cryo and high precision ovens and then forgers (not all) going a lot my eye and feel doing tempers in kitchen ovens.

As for multiple quenches being necessary for full martensite transformation this is also incorrect and that does not achiece that at all. There is however a benefit to repeated quenching but it isn't a higher percentage, you can get that optimal in one quench with full cryo and at the same time enhance high wear resistance carbide formation, not more carbide, but carbide of a different crystal structure this can not be achieved by low temp quenching no matter how often you do it.

The benefit to multiple quenching is that you can refine grain because it is an iterative process. Essentially every time you rerun the soak to quench, the starting process is effected by history and it thus further enhances the grain refinement. This however again is subject to the same laws as given before. You can't refine 52100 to an extent which gives the wear resistnce of D2 or the shock resistance of S7.

Much of the "performance" claims about such issues are hyperbola more so than fact. I have used such knives by the highest promoted maker, Fowler, and they fell far short of claims made and were readily outperformed by production blades costing much less and made from modern steels, I was not impressed at all.

Much of the claims come from how the blade is ground, and other facets of heat treating such as comparing a differential temper to a full hard blade and noting one cracks and the other bends, plus never comparing blades from other makers and thus the performance baseline is usually really skewed. It is why for example if you give a novice user and decent high end knife (Spyderco, Benchmade, Cold Steel) they will rave about how great the knife is, even though if compared to the spectrum it may be at the bottom of the list.

This being said I would be very interested to see someone like Kevin Cashen who I have always found to be hype free, to actually describe comparing a quality stock removal blade from a maker like Wilson and getting better performance out of a forged blade which is identical in shape due to the actual forging, and as noted before I offered to have such a comparison done, and would have payed for the steel and the heat treating.

Lots of great knives are being made by lots of forgers. This isn't to say they don't cut well, have great balance or toughness. It is quite simply to say that grain refinement isn't something inherent to hot hammer forging, it is simply a responce to steel stress which doesn't require a hammer, and quite frankly there are awesome steels out there which have insane performance levels which are not forged as this is hardly the only performnce criterion.

As for forging wasting less steel. This is nonsense. The cost of steel is irrelevant to the cost of a knife. None of the high end forged knives have the steel costs as a significant cost of the knife, it is minor percentage of the total cost, and it is completely a non-issue anyway as there are ways to recap stock waste by reusing the steel into smaller knives, etc. .

-Cliff

 

[GarageBoy]

Well..forged pistons and connecting rods in cars are preferred over cast. (A little O/T)

 

[jedi_pimp]

ErikD,
You should try one of Ed Fowler's knives for the ultimate in forged blade performance. He is supposed to have 52100 down to a fine art, getting the last bit of performance out of it. They are way out of my price range, but he makes them to be working knives, he tests them very much and they have to cleave through barbed wire and chop into a rail road tie, I think. Plus they look cool and have sweet sheaths.

 

[Josh Muller]

jedi, not sure if you noticed cliffs mention to fowler or not... just thought id point it out


im going to be building a forge if only for the purpose of being able to attain 3/4" stock wich otherwise would be unavailable. also to create billets or bar stock from miscellanious cut off pieces wich would be otherwise wasted (to small to create knives from).


i do doubt that the cost of steel wasted via stock removal (plus the long term wear on belts) would be that significant compared to the cost of the gas used to keep the forge going.

 

[jedi_pimp]

Seth,
nope, Cliff is on my "ignore" list right now. Anyways, I think Folwer is recognozed as the top forger in perfaps the world for super utlity high performance blades. He even wrote a book.

 

[Steven Roos]

i do doubt that the cost of steel wasted via stock removal (plus the long term wear on belts) would be that significant compared to the cost of the gas used to keep the forge going.

The actual cost of the steel is pretty small for carbon steels, and so is the cost of the gas. Those could probably cancel each other out.

Belts on the other hand...the belts cost a fortune! Forging the profile and bevels saves so much grinding it isn't even funny!

 

[Kohai999]

"As for forging wasting less steel. This is nonsense. The cost of steel is irrelevant to the cost of a knife. None of the high end forged knives have the steel costs as a significant cost of the knife, it is minor percentage of the total cost, and it is completely a non-issue anyway as there are ways to recap stock waste by reusing the steel into smaller knives, etc. -Cliff"

Forging does use less steel. That is not the cost issue. The cost issue is in time and sanding belts,which while inexpensive, are not cheap.

I have read Cliff Stamp conduct and publish his little tests via BF for years. He is sophomoric to the highest degree I have ever witnessed in a human. For those of you that do not know, "sophomore" means "wise fool". IF he was an accredited metallurgist and IF he was an experienced and accomplished blade forger/stock removal specialist, I would take what he said with a little more seriousness.

As far as I can tell, he is a student with a sharp mind, and way too much time on his hands.

Best Regards,

STeven Garsson

 

[Josh Muller]

"As for forging wasting less steel. This is nonsense. The cost of steel is irrelevant to the cost of a knife. None of the high end forged knives have the steel costs as a significant cost of the knife, it is minor percentage of the total cost, and it is completely a non-issue anyway as there are ways to recap stock waste by reusing the steel into smaller knives, etc. -Cliff"

Forging does use less steel. That is not the cost issue. The cost issue is in time and sanding belts,which while inexpensive, are not cheap.

I have read Cliff Stamp conduct and publish his little tests via BF for years. He is sophomoric to the highest degree I have ever witnessed in a human. For those of you that do not know, "sophomore" means "wise fool". IF he was an accredited metallurgist and IF he was an experienced and accomplished blade forger/stock removal specialist, I would take what he said with a little more seriousness.

As far as I can tell, he is a student with a sharp mind, and way too much time on his hands.

Best Regards,

STeven Garsson

i beleive cliff has a doctrate in physics, specifically... im gonna destroy this one.... in the study of how atoms in given materials react under heavy pressure and radiological exposure??? something like that. needless to say, he has all the technical backround needed to become a metallurgist. ive never heard cliff say anything here that he couldnt back with well thought out argument, and that he wouldnt be willing to change should a better argument arise (with logical explanation and preferably physical data).

*i could definitely be wrong about his droctrate, just as i am probably quite wrong (as was pointed out) on the cost of steel vs. the cost of belts*

 

[Kohai999]

I have no intention of setting myself up for debate with Cliff, or anybody else. What you CAN do and what you do are two different things. It is also the manner in which you do it, and why.

For instance: from Scientific American,The Mystery of Damascus Blades; January 2001; by John D. Verhoeven; 6 page(s). Dr. Verhoeven IS a metallurgist, and HAS published a work regarded well by the Scientific Community concerning the above subject. One of his students, Ed Severson(sp?) went to work for Crucible shortly after graduation from college, and was key in the development of the CPM steels, unless my memory is failing me. He has since moved on to Uddleholm.

Cliff COULD tear that article and the inferences apart(for all I know, he has done so), but has he made Wootz, and then run studies on it? Pendray did, and he worked with Verhoeven for the article.

See, it is all speculation on the part of the bystanders, unless they have specific training in the areas of concern. Developing tests, and destroying knives can be objective or subjective, depending on what you are trying to learn. I never said that Cliff was not smart. I do not know him, or what his specific disciplines are. I do know that he does not make knives for a living, otherwise I would have seen some for sale somewhere.

That makes ALL the difference in my book. What you do for a living. I have no doubt that a veteranarian COULD do brain surgery on a human being based upon skill sets, but I would not want my brain surgery done by a veteranarian, only by a neurosurgeon. Does this make sense?

That is why although Cliff may be smart, and have developed some creative testing protocols for knives, I will accept what Goddard, Fowler and Verhoeven have to say on subjects concerning blades and metallurgy over what he has to say ANY DAY OF THE WEEK.

Best Regards,

STeven Garsson

 

[A. G. Russell]

Very intersting thread. I am sure glad that I kept my opinions to myself. Since I have no doctorate and have not written a book, it seems that they would not have been well recieved.

I would very much like to see micro photographs of hand forged blades showing me the re-sizing and aligning of the grain. Surely someone more web-able than I can find sømething from a stél mill that will shed light on this subject.

A. G.

 

[brownshoe]

Hey Kohai999

This was uncalled for:

"He is sophomoric to the highest degree I have ever witnessed in a human. For those of you that do not know, "sophomore" means "wise fool"."

I've read a lot of your posts and you share many personality traits in common with Cliff. Maybe why that's why you react so negatively when his opinions differ from yours. If you think he's incorrect, remember even a broken clock has the right time twice a day.

 

[Alpha Knife Supply]

I would very much like to see micro photographs of hand forged blades showing me the re-sizing and aligning of the grain. Surely someone more web-able than I can find something from a steel mill that will shed light on this subject.

A. G.

A. G., come out to one of our hammer-ins and we will rerun the tests with you as a participant. We would love to have you there. Send me an e-mail if you are interested.

This invitation is open to anyone interested.