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Klaas remmen

Georgian 'Bulat' technology by Zaqro Nonikashvili

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Klaas,

Posts # 169 and #190 have been edited and new photos have been added.

 

Jan

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Hi Jan

 

The pattern of the forged bar looks very similar to the pattern of the ingot. Have you roasted the ingot for a long time or have you forged it 'raw'?

Is that a bar from the nice ingot you posted above?

 

Cheers

Edited by Klaas remmen

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Hi Jan

 

The pattern of the forged bar looks very similar to the pattern of the ingot. Have you roasted the ingot for a long time or have you forged it 'raw'?

Is that a bar from the nice ingot you posted above?

 

Cheers

 

Klaas,

The ingot the bar was forged from was a very old sample..but I have never roasted at high temperature and do not plan to do that as I have had some of my ingots bleed when I tried it. I cannot believe the material does not experience some (high temperature roasting during the first half of the forging period which I may have done at a higher temperature. The Persians forged their ingots in 1.5 hrs. ( by hand) ..that was not a cold ingot going through 400 cycles, that is for sure.

 

That very nice ingot shown above is no more...as I was beginning to forge it, I noticed some very crisp clear cracks at the surface ( I have never seen this phenomenon before) . Grinding only revealed more bad news.

 

Probable causes...I cooled it too fast , don't forget I was only interested to see if it ( the Georgian method) worked ( normally fast cooling gives me some surface cracking but not this)...I heated the ingot too fast....the cold rolled steel from my pile is suspect ...I did not grind the surface prior to heating ...or I do not know. The rapid heating ( of a fast cooled ingot) is probably the cause, but just to be safe when I repeat it, I am going to use home made wrought ( the blooms are actually being resized tomorrow, to a size I can handle on my 50 lbs hammer ).

 

I will do one more and then go back to cast/wrought for the rest of the time..I may even make some cast using the Georgian method minus the glass...just let it trickle out of the crucible into some water....all that charcoal and the bloomery it is sooo dirty.

 

Jan

Edited by Jan Ysselstein

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Klaas,

The ingot the bar was forged from was a very old sample..but I have never roasted at high temperature and do not plan to do that as I have had some of my ingots bleed when I tried it. I cannot believe the material does not experience some (high temperature roasting during the first half of the forging period which I may have done at a higher temperature. The Persians forged their ingots in 1.5 hrs. ( by hand) ..that was not a cold ingot going through 400 cycles, that is for sure.

 

That very nice ingot shown above is no more...as I was beginning to forge it, I noticed some very crisp clear cracks at the surface ( I have never seen this phenomenon before) . Grinding only revealed more bad news.

 

Probable causes...I cooled it too fast , don't forget I was only interested to see if it ( the Georgian method) worked ( normally fast cooling gives me some surface cracking but not this)...I heated the ingot too fast....the cold rolled steel from my pile is suspect ...I did not grind the surface prior to heating ...or I do not know. The rapid heating ( of a fast cooled ingot) is probably the cause, but just to be safe when I repeat it, I am going to use home made wrought ( the blooms are actually being resized tomorrow, to a size I can handle on my 50 lbs hammer ).

 

I will do one more and then go back to cast/wrought for the rest of the time..I may even make some cast using the Georgian method minus the glass...just let it trickle out of the crucible into some water....all that charcoal and the bloomery it is sooo dirty.

 

Jan

 

The blooms have been downsized and are ready for me to weld and fold a few times ( 2X normally). I am not looking forward to fluxing up my pretty kiln wash painted forge, which has mostly been used to melt and hammer some wootz.

 

The bloom I am using is a slightly high phosphorous .113% P bloom ( see http://www.bladesmithsforum.com/index.php?showtopic=20307&st=0 post#16, for a complete composition of the Bloom ). This material will be folded more than 2x, as I want to compare "bloom composition" to "bar composition" from the same stock..I will share the results of the bar's lab. analysis here. This particular bloom forged into a single 9 lb bar at medium heat...expectations are high for the material.

 

I will forge out some flat bars for the "Georgian Bulat method" , and try to do a melt ( with memory) this week end..

 

I have no idea about final carbon composition via this method...guessing is ok.

 

Jan

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The blooms have been downsized and are ready for me to weld and fold a few times ( 2X normally).

The bloom I am using is a slightly high phosphorous .113% P bloom ( see http://www.bladesmithsforum.com/index.php?showtopic=20307&st=0 post#16, for a complete composition of the Bloom ). This material will be folded more than 2x, as I want to compare "bloom composition" to "bar composition" from the same stock..I will share the results of the bar's lab. analysis here. This particular bloom forged into a single 9 lb bar at medium heat...expectations are high for the material.

I will forge out some flat bars for the "Georgian Bulat method" , and try to do a melt ( with memory) this week end..

I have no idea about final carbon composition via this method...guessing is ok.

Jan

 

 

 

The bloom was directly forged into bars, which were reduced to strips...no folding/welding was done. The 10 lbs. bloom now consists of 7.7 lbs of scaled strips which need folding/welding before use (rough). Standing in a hot crucible cannot be considered a function of use, so I will use these strips as they are (rough forged bloom) after grinding off the scale. Even after grinding I expect a little iron oxide to remain in the iron and to find its way into the slag.

Here are some pics of the bloom, the bars (2 of the 3 are .113 P ) and the unground strips. I will post what goes into the crucible as well and the rationale for firing the crucible a specific way.

 

 

 

Jan

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Wow Jan, that's interesting stuff! your iron looks very good! Some friends and I made a few ingots and a shaft furnace smelt yesterday, we also would like to see how the home made iron does for making crucible steel. If I get some pics I'll post them here.

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Wow Jan, that's interesting stuff! your iron looks very good! Some friends and I made a few ingots and a shaft furnace smelt yesterday, we also would like to see how the home made iron does for making crucible steel. If I get some pics I'll post them here.

 

 

Klaas,

If the home made steel doe well...I will be obligated by my conscience to repeat the cold rolled test...I fear being accused of not treating the ingots equally because I was not the father of the cold rolled steel. I want to remain as objective as I can.

The phosphorous in the metal should create a different look.

Jan

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A lot of good work Jan. I wish successful melting.

My last cake with Widmanstätten structure crashed...

 

Adam,

Those are fantastic helmets! Thanks for sharing them with us....are you trained in sheet metal work?

Thanks, no I am not trained in sheet metal work - I am self-taught

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Klaas,

The ingot the bar was forged from was a very old sample..but I have never roasted at high temperature and do not plan to do that as I have had some of my ingots bleed when I tried it. I cannot believe the material does not experience some (high temperature roasting during the first half of the forging period which I may have done at a higher temperature. The Persians forged their ingots in 1.5 hrs. ( by hand) ..that was not a cold ingot going through 400 cycles, that is for sure.

 

Jan

 

Klaas,

Here is an example of diffusion heating at too high a temperature...the whole concept of diffusion heating and the resulting decarburized shell is something I am a little confused about..it will clear later. I do not think home made steel is a requirement for a nice wootz bar. If the steel chemistry is close what has been studied and one can get clear patterns of cementite and a dark etching matrix it will look good. I did the home made route as a study project and have no regrets, I as have learned a lot. As one progresses in a topic like wootz making, other horizons appear and do not seem so threatening. Some of the topics tying into the wootz methodology are casting steel, shear or blister steel, making reusable crucibles, bottom tap reusable crucibles and playing with the iron making furnace to get the right balance of ingredients for wootz. The methodology of the Japanese smiths is also linked to the wootz topic, both are taking very high carbon iron and managing it into a beautiful object, the FeO is a demon to the wootz maker and a blessing to the Japanese blade smith.

 

By the way i have found some pictures and the original cake of a high phosphorous test ( unplanned )...when I get a cake forged from this bloom I will post them for comparison.

 

Here is a picture of an overheated wooz cake:

 

Jan

Edited by Jan Ysselstein

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What's that piece on top of the cake? I like the color of the ingot though.

Here are some pictures I got from Gotscha, from a new knife by Zaqro and another Georgian knifemaker, Gela.

mesZaqroGotscha.jpg

mesZaqroGotscha2.jpg

 

I made a big Bulat cake by using two ingots that went wrong during the smelting. I am now planning on forging this 1800gram ingot by hand and systematicly take metallographic monsters, to make the entire process more clear to myself. It will take a while, but when finished I'll put up the pics.

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What's that piece on top of the cake? I like the color of the ingot though.

Here are some pictures I got from Gotscha, from a new knife by Zaqro and another Georgian knifemaker, Gela.

I made a big Bulat cake by using two ingots that went wrong during the smelting. I am now planning on forging this 1800gram ingot by hand and systematicly take metallographic monsters, to make the entire process more clear to myself. It will take a while, but when finished I'll put up the pics.

 

Klaas,

That is a beautiful knife!

Good luck with the large cake...I hope you have some help.

The material flowing out of the shrinkage cavity in the photo above is whatever melted and expanded at the temperature it got to ( I did not have a thermocouple on my furnace and it would slowly get hotter and hotter). I was and am operating in the cast iron range and my ingots were somewhat cast iron ( very hypo-eutectic cast iron). I plan to do about 3-4 more in that carbon range and then begin to extract myself from wootz making by going back to melting hyper eutectoid steel wootz ingots ( using what the cast iron has shown me) . In the case of the topic of the thread.... to get to a lower carbon content.....I can just add more glass or run the whole thing at a higher temperature(s). The melting/forging remains on hold until I can get back into the shop this Fall.

Jan

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Wonderful work from the two Georgian makers! :blink:

It was nice to meet you some days ago! :D

See you soon with Patrick :D

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i had made a 40kg ingots from a Vaccum induction furance. then forged and hot rolled into sheets. it does shows the banding pattern, however because of the industrial forging and rolling progress, i got all the fiberous structure follow mostly one single direction. the pattern i got there is kind of too simple and boring. next time i am going to try get the pattern more livly.

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Wonderful blades!

 

This Wootz, and Bulat, stuff is just so interesting. I hope to add my random style of experimenting with this sometime soon.

It just looks like too much fun!

 

I have made a good bit of good looking cast iron doing some bloom smelts. (not on purpose) And lots of bloom iron.

It would be great fun to put some of these in a crucible, with some vegi matter, and fuel, and see what I get.

 

Fun and exciting posts gang. Drive on!

 

Mark

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Wonderful blades!

 

This Wootz, and Bulat, stuff is just so interesting. I hope to add my random style of experimenting with this sometime soon.

It just looks like too much fun!

 

I have made a good bit of good looking cast iron doing some bloom smelts. (not on purpose) And lots of bloom iron.

It would be great fun to put some of these in a crucible, with some vegi matter, and fuel, and see what I get.

 

Fun and exciting posts gang. Drive on!

 

Mark

 

 

Mark,

Bloomers and Buttons is my main topic of interest here. You and lately Lukasz ( Lukasz your work just amazes me) have provided so much context, I feel guilty for not helping out here and there. The higher phosphorous bloom mentioned in the discussion with Klaas ( above in post 205 ) is still waiting to be carburized and forged into a "wootz" sample. The test should start sometime this week/weekend .

 

The strips will be as forged bloom, 6-8mm thick , ground clean and any very dirty folds revealing lots of slag will not be used.....the rationale....in India ( though we are calling it "Georgian" we (I) really mean "Indian") , this was a process taking place on a large scale. We romanticize over a single ingot, but their small teams ( In india ) were making 4 x 15 or 5X15 a day...about 60 a day . Any saving of labor ( as in folding the bloomery iron ) would be a big improvement in efficiency for someone in the supply chain. Another reason for not folding the bloomery iron is unrelated to "wootz".....I will be making "blister steel" out of the same material ( same process as the wootz, only less time in the oven) . For the forged and welded "blister steel" or "shear steel" to have lots of character ( soul) and show an interesting hamon , my guess is the staring material should be rough( I may be wrong here, time will tell ) .

 

The crucible will be a bit smaller in size, as I am shooting for a 700 gram ingot on my second attempt at this method. Gas as fuel , carbonizing agent is any form of carbon ( sawdust , charcoal and so on)..... several large fresh leaves from the sacred tanoak tree will be included to make it an authentic, romantic experience. The glassy phase will be very small compared to previous discussions on this thread.

 

Next step is to "fit" the desired weight of iron strips into the smaller crucible..( record the total surface of clean metal area available for the absorption of carbon ) and fit that to my previous assumptions regarding the rate of carbon absorption. This simple arithmetic step will give me the minimum time the crucible should be at "heat" . I will post a photo of the ingot top surface after carburization and the forged bar, after drawing it out.

 

Jan

 

Edit, Dec7.... Crucible problems ( operator problem ) will delay the test by at least 1 week ..control material still has to be gathered.

Edited by Jan Ysselstein

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Jan,Sorry to see those cracks....I have a few hundred pounds of those cracked ingots holding the shop floor down.

I have never found it useful to melt a bad ingot a second time.I always start again.Ric

 

Hi Ric,

Rereading this thread I again stumbled over this post. I should be coming over and clean up a bit, I thought at first :D

and then I thought about all the help I got, when writing about melting desasters or cracking strips. I was told many times to simply reuse the stuff and remelt it. Achim told me that he does that with the material he gets from his smelts regularly, with good results.

Maybe it is hard to remember the exact materials used, after leaving bad ingots on the floor - amount of C and other elements,

 

hmm,

I still did not build up my new "shop", but I would gladly use and remelt old stuff - it really does not get bad, if you grind off the rust. All smithes re-use old stuff, don't we?

best regards

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Hi Ric,

Rereading this thread I again stumbled over this post. I should be coming over and clean up a bit, I thought at first :D

and then I thought about all the help I got, when writing about melting desasters or cracking strips. I was told many times to simply reuse the stuff and remelt it. Achim told me that he does that with the material he gets from his smelts regularly, with good results.

Maybe it is hard to remember the exact materials used, after leaving bad ingots on the floor - amount of C and other elements,

 

hmm,

I still did not build up my new "shop", but I would gladly use and remelt old stuff - it really does not get bad, if you grind off the rust. All smithes re-use old stuff, don't we?

best regards

 

Jokke,

I am speaking for myself only as an accumulator of "rework" wootz. One dare not place a whole cake in a crucible of the same size that cake has cooled in...although the cake contracted..it will expand again to the "hot dimensions" and if anything falls between the wall and the ingot the crucible will break. Do I want to cut a bad ingot into pieces or just add some ingredients and move on...the latter is often the easiest. One of the observers of the Indian crucible steel making process noted the iron from broken crucibles which fell into the charcoal fire and became highly carburized was not re used but sold to the maker of firworks.

 

Jan

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Jan,

thx for the reply,

I did not want to say, "just put the thing back!". but:

there might be a "trick" to do it in a way not to ruin the crucible, (although normally I do cut the leftovers into pieces when doing a remelt),

it is to put enough glass (one that needs about 1000°C to melt) into the crucible so that the ingot does not touch the sides, when the crucible is re-heated, the melting glas will keep the ingot up long enough, so it too reaches temps and does not expand anymore, before it sinks into the molten glass to touch the bottom of the crucible.

I was told that by Achim some time ago and used the method twice since, without braking the crucible (using clay-graphit ones)- I did not want to cut the ingot lacking the proper cutting-disc at the time and did not want to wait.

 

Well, if I had pure cast iron I would first try to get a guess on the amount of C, before I would use it in a melt, for sure

we do have more knowledge about the chemistry of steel, nowadays,

so why not use it...

 

best regards

 

PS for the admins:

would it be a new threat on: remelts of failures in wootz!?

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Jan,

thx for the reply,

I did not want to say, "just put the thing back!". but:

there might be a "trick" to do it in a way not to ruin the crucible, (although normally I do cut the leftovers into pieces when doing a remelt),

it is to put enough glass (one that needs about 1000°C to melt) into the crucible so that the ingot does not touch the sides, when the crucible is re-heated, the melting glas will keep the ingot up long enough, so it too reaches temps and does not expand anymore, before it sinks into the molten glass to touch the bottom of the crucible.

I was told that by Achim some time ago and used the method twice since, without braking the crucible (using clay-graphit ones)- I did not want to cut the ingot lacking the proper cutting-disc at the time and did not want to wait.

 

Well, if I had pure cast iron I would first try to get a guess on the amount of C, before I would use it in a melt, for sure

we do have more knowledge about the chemistry of steel, nowadays,

so why not use it...

 

best regards

 

PS for the admins:

would it be a new threat on: remelts of failures in wootz!?

 

Jokke,

I have done it using a few lumps of charcoal under the ingot ( I think glass will melt before the iron ). This works only if the crucible has quite a taper.

Jan

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Guys.

 

Have done many remelts whit no props / issues by the crucible, whit out any spesial tech´s..just

ingot in to the same crucible ( new or used) some "slag" on top

 

Crucibles that I have used will expand faster than steel ingot anyways....but why remelt if its ingot, just forge it out and see if its good or not....if not remelt is ok.

 

Why I did it then, was thought that ingots should be nice and smooth...but even bad lookign ingot it is...forging will give it one chance.

Some times even bad looking ingots turn out great.

 

 

Niko

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The crucible will be a bit smaller in size, as I am shooting for a 700 gram ingot on my second attempt at this method. Gas as fuel , carbonizing agent is any form of carbon ( sawdust , charcoal and so on)..... several large fresh leaves from the sacred tanoak tree will be included to make it an authentic, romantic experience. The glassy phase will be very small compared to previous discussions on this thread.

 

Next step is to "fit" the desired weight of iron strips into the smaller crucible..( record the total surface of clean metal area available for the absorption of carbon ) and fit that to my previous assumptions regarding the rate of carbon absorption. This simple arithmetic step will give me the minimum time the crucible should be at "heat" . I will post a photo of the ingot top surface after carburization and the forged bar, after drawing it out.

 

Jan

 

Edit, Dec7.... Crucible problems ( operator problem ) will delay the test by at least 1 week ..control material still has to be gathered.

 

This is my first test using the Indian method of carburizing bloomery iron to wootz..very similar to the Georgian method ( maybe a little less control over carbon content).

So we have a few leaves (Tanoak)

705 grams of raw bloomery iron

14 grams of charcoal , the charge contains an excess amount of carbon to compensate for porosity, I really only need 11 grams to get 1.5%C

a pinch of enameling fritt (a few ml)

A completely "sealed" crucible which I will attempt to glaze..glaze is not always effective in reducing penetration of oxidizing gasses (O2,CO2), my confidence in the seal is limited

As can be seen on the strips of bloomery iron there is still a bit of slag and or iron oxide on the metal

 

 

 

Jan

Edited by Jan Ysselstein

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