khukuri steel

J

Johan van Zyl

Joined
Oct 11, 2000
Messages
372

I compiled a few thoughts, with the help of Lewis & Combs (1992) for the possible benefit of forumites. I am far from being an expert, but I like to consider things that interest me. Please comment if you don't agree with me. I am open to suggestions.

Forging a blade

It is said by people familiar with forging as a method of shaping blade steel, that it is the only way, albeit an old-fashioned way, to achieve real strength and edge- holding ability. We know that the blades of khukuris are shaped in this way. A properly forged and packed knife can hold a good edge and have a spring temper, it is claimed, even without heat treatment. When heat-treated its edge-holding capacity is reportedly unsurpassed.

In industry, forgings are specified for high strength parts. This fact must have some implication in knifemaking. But one seldom hears of blades, besides khukuris, being made the old-fashioned way. Today, most modern quality factory made and benchmade knives are ground out of bar stock or even investment cast. The famous makers don't seem to want to admit forging is a better method.

The blades of all well-made, traditional khukuris are forged. However, the cheaper Indian khukuris are also forged, as one can tell by looking along the length of the blade in the light. In high quality khukuris, I expect, there is superior quality control over the various stages of forging. We could call this: the eye of the expert kami...

Grinding an edge

Hollow-ground blades are common in quality knives, but they are said to be so delicate they can't hold an edge under heavy usage. As can be seen under a microscope, the edge seems flimsy. Under pressure, the edge can be expected to chip rapidly and turn the edge off. Hollow-ground edges occur naturally when a knife blank is clamped against a jig and pushed against the wheel of a belt sander. Conversely, a good convex sabre-grind works better. This, I believe, is the type of edge put on khukuris.

I realise that if you are sympathetically inclined towards the objects of your interest, you might overlook shortcomings, and you might magnify good qualities in order to make your point. That is why I do not actively stop myself from criticising khukuris, or hearing khukuris being criticised.

But I think from what has been summarised above, khukuris do have some good points stacked in their favour!

We know there are more, much more.
 
Interesting point you make of being blinded by personal biases and losing one's objectivity. I wonder what happens in the molecular structure when steel is forged that makes it so beneficial to khukuris and other knives.
 
Lt. Dan, I am going to try to contribute something in answer to your question about the molecular structure, although it might stir up a hornet's nest. But if it is going to get the real experts on the line, we can only benefit from their knowledge and understanding.

Lewis & Combs explains that hammer-forging aligns the crystalline structure of the steel to create a more resilient blade. They say a hammer-packed edge is not only tougher, but takes a higher degree of sharpness and holds it longer. Well, I tried hard to understand statements like these. It seems to me that steel has grain, much like wood. The "flow" of the grain in steel, and the alignment of the crystalline structure of the metal, seems to me to be one and the same thing. I assume that when you take a billet of steel as it comes off the presses, the grain is aligned along the length of the steel. When a knifemaker grinds a curved blade using the stock removal method, he actually cuts against the grain in some parts of the blade. For instance, when he makes a khukuri, a certain part of the blade will be cut at an angle into the grain. The knifemaker has no control over this. It is the same if I make a khukuri blade from wood. Eventually I will have to cut across the grain in some parts because the blade is not straight. Now in forging a piece of steel, the grain flow becomes aligned along the forging lines. I think this statement is the crux. For instance, if you forge a khukuri blade, the grain flow now follows the curve of the blade. This is how I see it. In this way the steel is strengthened by forging.

Compare the strength of a hoop-shaped armrest of a chair made from rattan, in which the grain follows the curve due to the bending process, with an armrest made from a solid piece of timber machined out. My judgment is that the armrest in the case of the rattan will be able to withstand more abuse than the one made from a machined piece of wood. In the same way, I think, forged steel is stronger.

I shouldn't be writing about this; I have too little experience, but I like to seek out answers!
 
You go, Johan! Just keep on churning this stuff out; you're a regular research machine! This is excellent material with a good attitude. After all, your purpose is to learn more, as well as encourage others who can contribute to shed some light on the subject. It's well-written, too.

I guess a hammer would help get some steel molecules in order, for sure. You may also have heard of cryo treating rifle barrels. That's said to align the molecules and relieve the stress, thus allowing the barrel to stay straight when heated by multiple discharges (optional on many high-dollar custom rigs). I'm not trying to give you another assignment, but I'm getting curious about comparing the results of this process and hammer forging. I'll try to look into it. There's an excellent knife maker who sends his blades to California to get the cryo treatment after the metal work is done and before mounting the handles. (I'll ask him by the middle of the month.)

There's something good and primitive about hammer forging, though. Somehow, exposing knife steel to liquid nitrogen just doesn't have the same appeal. Those images of the master khukuri makers are burned into my mind, and it kind of seems right to me. Say, have you gotten Craig's video, "Gurkha Steel"? It's just AMAZING.

And I hope that Forumites will set me straight if/when my posts are lacking in accuracy. Later....Dan
 
Lt. Dan, you are too kind! No, I don't think I have heard about the cold treatment. Thanks for bringing it in. No. I have not seen Gurkha Steel. Yes, I'm going to get it! I wrote Craig about it, and he rightly said (being a businessman) that it would be cheaper in terms of total postage to this faraway country to order the video AND a khukuri. He's quite right of course, but the problem is, there is a Cheetlang on the way for me, due to arrive by coming weekend, and after that there is an oldie (elsewhere) which I have decided to order, and only after THAT can I scrape together the filthy lucre needed to get the video and khukuri (I think I'll have the Afghan). I am writing all this to possibly further whet the appetites of all you forumites who have been bitten by the khukuri bug as I have been. And the reason for my writing in this topic about khukuri steel is because it is mainly the steel of the blade that makes the khukuri what it is. We HAVE to consider the steels used and what makes for good steel. And if it means glorifying the khukuri because it is forged, then so be it.

"Gold is for a woman - steel is for a man."
 
Johan,
Interesting research on forging however, the metallurigical improvements of grain flow is primarily for parts that will be machined to final product directly from the forging. The forging does not undergo any additional heat treatment (other than low temperature stress relief for stability).

I believe the advantages of forging a steel blade go away when the hardening process is undertaken. Above the transformation temperature of steel the structure changes to Austenite and the forged grain disappears. If the transformation temperature is not achieved, hardening cannot occur. Fast temperature change (quenching) developes Martensite, this allows the property of a unique structure to be locked into the carbon iron crystal.

The time for quenching depends upon the alloys in the steel, water hardening is fastest and air hardening is slowest.

The additional step of Tempering is necessary for removal of brittle properties in "as quenched" steel, this is where "glass hard" applies, drop a thin piece of high carbon steel "as quenched" onto a concrete floor. Tempering temperature is well below the transformation temperature; 300-900 F, depending upon the alloy.

The process in Khukuri steel is possibly a unique combination of special events. The steel is from truck leaf springs, alloy unknown, I assume sourced from junk yards. The blade is forged from relatively thin stock and then the is edge heated to some temperature based upon color. The blade edge is quenched with water to harden. The spine of the blade may retain some of the forging advantages if not heated equal to the edge area. I beleive the blade edge is NOT Tempered (based upon photos on Gurka House site). The low Rockwell hardness of edge and very low spine Rc, indicates low % carbon. My conclusion is the very well develped edge geometry allows heavy choping and lack of edge chipping in harder materials. Has anyone done rope cutting tests for edge holding properties?


Very low temperature for additional properties has been arround for many years. The bearing industry has used it for post heat treatement of high carbon 52100 steels and many high performance automotive engines and aircraft components are treated at 300 F below zero. Rifle barrels for target shooting show better accuracy and longer life, razor blades will last many time longer after deep freeze, musical instruments made with brass will sound sweeter and women's nylon stockings will last longer before tearing. Some of the the knife makers who use cryo process are Chris Reeve on BG-42 Sebenza models and the former Blackjack knife company there are other factory blades I am not aware of. Many of the custom makers also will send their blades out for cryo process.

I will research some internet sites and post URL's in next few days.

Regards,
FK
 
Links to related sites: Forging, Heat Treating, Forged Knife Makers.

Hours of research and interesting reading.


http://www.astm.org/DATABASE.CART/PAGES/A711.htm
(American Society for Testing Materials - Forgings)

http://www.livelyknives.com/ntarticles.htm
(interesting articles on forged knifemaking)

http://pub4.ezboard.com/btheneotribalmetalsmiths
(BB for hand forging of many materials)

http://www.livelyknives.com/metalinfo.htm
(metalsmithing links)

http://www.westyorkssteel.com/Heat_Treatment/htchart.htm
(color charts for heat treating and tempering)

http://home.flash.net/~dwwilson/ntba/archive/junksteel.html
(junkyard steels - note: leaf springs = 1085 and 5160)

http://www.steelforge.com/infoservices/infoservices.asp
(Specialty Steel and Forge - interesting info.)

http://siriusweb.com/Fremlin/forum/messages/769.html
(BB discussion on Annealing to set up forged blade prior to hardening, what happened to the grain structure formed in forging?)

http://www.americanbladesmith.com/
(American Bladesmith Society - dedicated to forged blades, note the Journeyman Smith Test details)

http://swordforum.com/


Regards,
FK
 
FK, thanks for the thought, time and effort you put into the above posts...a truly great read. And I hope these won't be your last here. No doubt, Johan will be overjoyed.

Johan, I assumed wrongly that you knew of Gurkha Steel. Shame on me for not recommending it to you. Afghan?! The Cheetlang will blow your mind (and probably become your favorite), but the beautiful form of the Afghan might just knock you out! You're setting yourself up for a special treat and may never be quite the same afterwards. I don't want to say too much about this in advance, but want to learn of your reaction as it happens. Deal?
 
Well, well, well. This is stupendous!

Lt. Dan and FK, I thank you most wholeheartedly for your inputs. These need to be very carefully digested. In the meantime, let me put in a few more thoughts about this topic, which I compiled over the last two days. PLEASE REMEMBER, IT WAS COMPLETED BEFORE READING FK's CONTRIBUTION, AND THEREFORE DOES NOT CLAIM TO DISAGREE. OK, FK?

According to one of the khukuri websites, kamis prefer to use Mercedes Benz or Saab truck leaf springs, if they can get them, to make khukuris. I think it is safe to assume that vehicle leaf springs are made of the so- called carbon steels and possibly also alloy steels, both of which are non- stainless.

Carbon is present in all steels, but in varying quantities. It is the most important hardening element, and it also increases the strength of the steel. Knifemakers want knife-grade steel to have more than 0.5% carbon, which makes it "high-carbon" steel. Khukuris are reputed to be forged from high-carbon steel.

These are the steels most often forged. Carbon steels can be differentially tempered, and the kamis have been using this characteristic to good advantage, giving the steel a hard edge and a tough springy back. Of course, carbon steels are prone to rust.

Let me admit, I don't know exactly and specifically which carbon and/or alloy steels are used in the manufacture of truck leaf springs. The Encyclopaedia Britannica states that spring grade steels range from 0.85% to 10.5% carbon, used in a heat-treated condition. I read up on some material about steels compiled by collector and knifemaker Joe Talmadge, and I believe the leaf springs might be made of one or more of the following:

5160 steel

This alloy steel, popular with forgers, has about 0.60% carbon. It is essentially a simple spring steel with chromium added for hardenability. It has good edge holding qualities, but is known especially for its outstanding toughness. Quite often used for hard use knives, hardened up near the 60s Rc. I think this might be a likely candidate used for the truck leaf springs.

1095 steel

This carbon steel (belonging to the AISI 10-series) is the most popular for knives. 1095 is sort of the "standard" carbon steel, and it performs well. It is reasonably tough and holds an edge very well. This is a simple steel having 0.95% carbon and 0.4% manganese as an alloying element. This might have been used in the manufacture of some truck leaf springs as well.

O-1 steel

Belonging to the SAE designation system, this is a steel very popular with forgers, as it has the reputation for being "forgiving". It is an excellent steel, that takes and holds an edge superbly, and is very tough. We will have to find out whether this steel is also a likely candidate.

This morning Joe Talmadge contacted me by e-mail and suggested that 5160 steel is probably used in the making of truck leaf springs.

Regarding the preference the kamis have for Mercedes Benz and Saab truck springs, I ask myself on what grounds do they base that preference. Surely it is through experience in the forging of the various steels, in terms of the quality of the final product, that they are able to stand back eventually and declare they prefer this or that.

Hammer-forging allows the kami to change the shape of the steel. As an added bonus, the flow lines are arranged more or less parallel to the finished surface (as has already been pointed out), and the lines take an easy curve around corners. As the spring steel is heated and hammered, it becomes more brittle and hard. It may be necessary to bring the steel back to its original state by annealing (heating and then cooling slowly), if the desired shape is not yet reached.

I don't think there can be great variation in the "feel" of different spring steels when hammering it on the anvil. So somewhere along the line quality checks must be made on completed khukuris, and it must have been found that khukuris made from Mercedes springs conform best to the qualities desired in the best knives.

The question is my mind at the moment concerns the changes (if any) which might occur in the metallography of the leaf spring steel during hammer-forging...

So much said. Now I (we) will have put this all together and see what we can learn from it. Thanks once again for your contributions. Lt. Dan, I'll report on the Cheetlang etc. Like the South African cricket commentator exclaimed after a truly magnificent catch: "What a boytjie, what a boytjie!"
 
(My first double post. For shame...almost as bad as an incorrect sharp or sponge count, or that flyer that strays cleanly away from that one ragged hole in the paper.)



[This message has been edited by Lt. Dan (edited 03-08-2001).]
 
Johan: First, can you tell me how you pronounce "boytjie", and what does it mean? Sorry, but I've just gotta know about this one. I guess the Webster Dictionary folks thought guys like me ought to stick to their basics first.

Next, it's going to take me some time to digest all the above great reference material. It's doubtful my posts will have the full understanding all at once, but I'll take it in chunks. So when it comes to putting this together you might be the one leading the buffalo stampede (just don't trip!).

Wow, thanks again FK! Johan, you also bring up some interesting points. The supply of excellent steel to the bishwarkamis is of particular interest to me. It's not the easiest thing to spit out the seeds when reading internet posts, and I'm fortunate enough to know some people in real life who can discern forum folklore (however well intended) because of their deep knowledge of things like: knives, ballistics, firearms, martial arts, and medicine/surgery. It's been brought to my attention (and not by any forumite) that high-end European trucks and autos aren't exactly in great abudnance in Nepal and India. A steady supply of such springs for khukuris is, however, a wonderful notion indeed. I'll have to ask a buddy who specializes in the repair of Peugeot, SAAB, Mercedes, etc. about the springs. Granted, he doesn't do trucks and frame alignment, but he may be able to tell me if such leaf springs have any identifying name brand markings. Some salvage yard workers might know also.

That said, I want to assure all forumites that there is no intent here to discredit anyone, forum, or business in any shape or form. What I'm after here is to learn how the salvage and steel supply thing works. Sometimes things like this aren't like we assume, even if they do raise the esteem of the khukuri in our own eyes. Remember, we're talking about business in a very different place and culture.

I hope Craig and other forumites can contribute here. A little help, please....Dan
 
Lt. Dan, thanks for your latest contribution. I read with interest and echo what you say. What a pleasure to delve into khukuri hard facts with you guys.

One: I was able to have a look at a table of junkyard steels by the North Texas Blacksmiths Association stating that leaf springs are made of 1085 and 5160 steels. Thanks to FK who put me on the track of the website.

Two: Although the kamis PREFER Mercedes and Saab, it does not imply they actually get it. Your next khuk might be forged from a piece of Lada spring. So, that's bad, isn't it? But, it seems, on the other hand, inferior heat treating of even the best steels will yield an inferior khukuri. Now hardness of steel (you will know about this) is generally measured by units known as Rockwells on a scale known as the Rockwell "C" scale. I found the following guidelines very informative:
20-25 Rc Mild Steel. Many of the fake Highland swords are not heat treated and are at this level. Edge retention is poor.
30-40 Rc The minimum softness that should be allowed.
40-45 Rc This hardness level will have some spring qualities. Ideal for spines of khukuris?
50-52 Rc This gives a good balance between toughness (slightly soft enough for shock tolerance) and hardness (for edge holding).
58-60 Rc Ideal hardness for the edge of differentially heat treated Chinese and Japanese swords, I believe. What about khukuris? An edge of this hardness can cut into most materials that are comparably softer. Anything over 60 ventures into brittle territory.
All this tells me that "a knife with a hard edge is a good knife". In Khukuri FAQ Dan K. once stated "You should't make too much over the relative hardness of the edge". He mentions Gurkha Regiment blades with a hardness of Rc 58 on average. I read that Lal Bahadur (Bura) has his edges at about Rc60. Dan says hardness does not make one blade better than the other. Harder edges are more prone to chipping, and softer blades tend to roll and dent. I wonder if we shouldn't request Craig very nicely to tell us what he knows about the Rockwell hardness of the khukuris he deals in?

Three: I've a problem with the spelling of bishwarkami. Bill Martino in Khukri FAQ spells it "BISHWAKARMA". I assume the difference is significant.

Four: This one, slightly off the khukuri track, is for you specifically, Lt. Dan: You already know the word "boy". In my home language, Afrikaans, we add on "-tjie" to signify small size, but also acceptance, familiarity, love, sometimes even respect. Eg. it sounds more loving to say (in Afrikaans) "my dogtertjie" (my little girl), than "my dogter" (my daughter). It sounds more acceptable to say "Ek het ‘n brandewyntjie gaan drink" (I had a small brandy) instead of "Ek het brandewyn gaan drink" (I had brandy"). You see, the "-tjie" makes the difference. Now you know the exclamation: "What a man! What a guy!" Change this to "What a boy!", then alter the "feeling" of the exclamation and at the same time bring in true South Africanism by adding "tjie"! And you have "What a boytjie!" Pronounciation in English: BOY-KEY and you've got to say it quick. NB: this word does not appear in self- respecting SA English or Afrikaans dictionaries. This exclamation was used by a cricket commentator and the next day everybody was talking about it.
BEST REGARDS
 
The only one I had tested was actually tested by Blade Magazine.

<font face="Verdana, Arial" size="2">
Before I went to work whacking, chopping and splitting, I wanted to get some hardness numbers. I sent the blades off to SCK in Clancy, Montana, for a quick RC test. These blades are forged with truck springs, heated in a fire and tempered with a teakettle! MY thought was that control over the tempering process might be a little spotty. I was wrong.

It turned out that the blades were differentially tempered surprisingly well. The spine on the blades read 22 and 25 RC respectively. The midpoint of the belly measured in at 45 and 46 RC and the edge came in at 54 and 55 RC, not bad for some guy squatting around a fire in sandals!
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Click to expand...

That was from Ron Hood. And he proceeded to carve a frozen elk leg in two with very little noticable damage to the edge, which he restored in about five minutes with a file.

------------------
Craig Gottlieb
Gurkha House
Blade Forums Sponsor
 
Craig: Your khukuris must have pretty hard edges. They destroy new Nicholson files where the blade is zone hardened. That was a good article, worthy of a re-read. Thanks.

Johan: You've definitely got the research machine in high gear now, and I like it. For example, giving all those Rc ranges fills in some gaps for me. Agreed, there's more to a good khukuri than just how hard the edge is. Neither does an excellent piece of steel guarantee the utmost in quality. On one hand, you can't make chicken salad with chicken poop; but it's also true that a master craftsman can compensate to some degree with average materials to make a very good product. Yes, it would interest me to know how often the khukuri makers can get the premium leaf springs. But there may be no way to know for sure.

I don't know how it is with Afrikaaners, but way too many of us Americans like to look for a quick fact or name brand and use that as the acid test. The danger of this is that such a judgement is made on superficial knowledge alone. Unfortunately, I have some experience in this matter.

Another point well taken is the courtesy of using names to the best of out ability. Part of my job involves meeting new people daily, and lots of unusual names pop up in this university town. Because I'm a southern/hillbilly mushmouth, the best thing is for me to just ask up front how names are said, give it my all, and offer a respectful apology when appropriate. We have some fun with it and folks always seem to understand. That said, there aren't always exact translations. We see lots of little differences in words and names on these forums in our attempts to speak Nepali. I don't want to blunder ahead with offenses out of ignorance, so I appreciate updates from everybody.

Maybe it ain't quite so, but discussion of these khukuri issues is beginning to give me "a keen grasp of the obvious".

Also, many thanks for explaining "boytjie" to us. The spouse and I think you painted a clear verbal picture, and we shared a hearty laugh before work this morning. A good one, Johan.




 
Hmmmm...still double posting when composing off line and coming back on to post. Definitely a case of being computer challenged.






[This message has been edited by Lt. Dan (edited 03-09-2001).]
 
I've got a job ahead of me now. I have to put all this stuff together in a single document (probably about ten pages) and edit it severely. When I am done, I still need to decide what to do with the end product. (Remember, I started doing this to improve my own knowledge about khukuris.) If forumites want it, I can relinquish the end product as a new post on the forum in about a fortnight's time. But then with the understanding it is still only a draft, open to even further critical scrutiny by forumites, which I am going to welcome.

By the way, Lt. Dan, I shared your spouse's mirth about the "boytjie" issue with my lady colleague, Louise (a horse lover), who promptly replied: "Tell Dan I have a show gelding called Boytjie!" This name, sensitively interpreted, would mean something like "young guy" or "little man". Something else in this vein struck me the other day, and I was looking for an opportunity to share it with you and all other forumites: In the USA "Star Trek" has captured the minds and hearts of millions of Sci-Fi nuts. People go crazy about the Star Trek television series and the Star Trek movies. I just want to state for a fact (unless you can refute the statement) that the word TREK (in the context that it is used) is an Afrikaans word! In noun form, as used in the name Star Trek, it means "journey". In the middle 1830's in South Africa, there occurred a significant relocation of white farming people who could not bear the continuing oppression of the government of the day, and who decided to rather pack their belongings in their oxwaggons and move northwards and westwards towards a new and better future. This went down in history as "DIE GROOT TREK" (the great trek).

"Gold is for women; steel is for a man"
 
Johan, this boytjie thing has really taken off! Interesting parallel about the trek. Some of our own Native Americans have experienced that also.

You've done so much good research already. I hope this work in progress doesn't get out of hand. Granted, there's so much good stuff you're working up that will benefit us all, and I'm looking forward to it. It sounds like an impressive project, and I'm a little concerned it might wear you out.

What seems good (if possible) is to start a FAQ section (or equivalent) and create a file for future reference for all forumites, visitors, and newcomers. This deserves not to get buried in the postings.

Craig, what do you think about this?
 
This was also my problem with heat treating, as shown on GH site photos.

------------------------------

"Before I went to work whacking, chopping and splitting, I wanted to get some hardness numbers. I sent the blades off to SCK in Clancy, Montana, for a quick RC test. These blades are forged with truck springs, heated in a fire and tempered with a teakettle! MY thought was that control over the tempering process might be a little spotty. I was wrong.
It turned out that the blades were differentially tempered surprisingly well. The spine on the blades read 22 and 25 RC respectively. The midpoint of the belly measured in at 45 and 46 RC and the edge came in at 54 and 55 RC, not bad for some guy squatting around a fire in sandals!"

------------------------------

Are the blades tempered or only quenched?


The results in field testing are very impressive. One important point,,,,the pouring of water from teakettle onto blade is actually the "Hardening" process or sometimes called "Quenching".

The carbon and iron matrix must be frozen in a special crystaline form known as "Martensite". This process is time and temperature sensitive, in other words we have a given amount of time to lower the temperature of the steel which will allow harding to occur. textbooks will call it "TTT" or Time Temperature Transformation or sometimes refered to the Nose or Knee of the Curve.

The teakettle with water is not Tempering (also called Drawing), this is a second step after the quenched steel is brought to room temperature. To remove the "glass hardness" of Rc 63-64 the steel is reheated slowly to 300-900 F depending upon the alloy and Slowly cooled to room temp. The special alloys will benefit from a second or even third cycle of tempering. The final process is Cryo or deep freezing to transform any retained Austenite in the Matensite structure.

Many people interchange tempering and hardening. Hardening is the total process of heat treatment. Tempering is only one step.

Interesting references:


Definition of Heat Treatment for Steel:
http://tpub.com/air/15-29.htm
Ferrite, Austenite, Martensite and Carbon in solution with Iron these are the elements of Heat Treating. The crystal structure B.C.C. changes to F.C.C. at the critical temperature.
http://tpub.com/air/15-30.htm


Heat Treatment of Steel
http://www.ce.berkeley.edu/~paulmont/CE60/heat%20treatment/index.htm


Time Temperature Transformation Diagram:
http://www.ce.berkeley.edu/~paulmont/CE60/heat%20treatment/sld008.htm


Crystaline Structure Change of Martensite:
http://www.ce.berkeley.edu/~paulmont/CE60/heat%20treatment/sld011.htm


This explains the blacksmith trick with magnet indicating time for quenching.
B.C.C. = Body centered cubic = Steel below transformation temperature = Magnetic
F.C.C. = Face centered cubic = steel above transformation (critical) temperature, NOT Magnetic.


Older Machinery's Handbook 1924 ed. with excellent discussion on heat treating steels.
http://www.newmex.com/ebear/metal/heattreat0.html#hard


Annealing (discussed as pre treatment prior to harding by smiths, note the hammering or forging properties are removed)

http://www.newmex.com/ebear/metal/heattreat5.html#steel
The purpose of annealing is not only to soften steel for machining, but to remove all strains incident to rolling or hammering.

Note the S.A.E designations are now A.I.S.I. the carbon steel alloys (1095) are unchanged.

Enough for now, getting a headache from reading all this material.

Ultimate Question "Does Forging produce a blade with metallurgy quality superior to stock removal (grinding)"?????

Regards,
FK
 
By the way . . . great topic! We may want to consider making some form of this available to people on our website. What do you think?

------------------
Craig Gottlieb
Gurkha House
Blade Forums Sponsor
 
Craig: Absolutely! it would be super to edit this thread and make the info readily available on the GH website in an additional file under Research.

Say Craig, can you ask Lalit about the quenching process? Maybe FK would be able to tell us more about tempering vs. quenching if we knew more. While Gurkha Steel shows part of this process, these details aren't obvious to me.

FK, what you're bringing to the forum is right on the money for us khukuri enthusiasts. Please feel free to add your thoughts and summaries.

Many, many thanks to all....Dan
 
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