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Klaas remmen

Georgian 'Bulat' technology by Zaqro Nonikashvili

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Niko... cool down... :blink:

 

Russian is my mothertongue, i can read and translate a bit. Anosov used scale to create a composite slag. It is written in his Lab.Books.

 

Burned ingot - means too much oxygen in the steel. "Swiss cheese" ingot - one of the forms. This porosity can be invisible a the beginning but eventually will come out in forging.

 

IM totally calm??? <_<

Did I had tone in it?? :blink: Im so sorry :(

 

But thanks ones agane clearing some issues form me!

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just to clear some things out;

 

the photo`s I posted are taken from the exact same place as those in earlier post. Thus the structure is transformed from completely spheriodised, and some blocky cementite to this veryveryvery fine pearlite and graphite.

The specimen I took was from the absolute end of the bar(4mm of `fishlip`), because I don`t like to waste this stuff... I could take a specimen from the place I took the picture of the pattern, but than I would have to cut it in half. I`ll take another specimen from the side, to see wheter the structure is better there, or the graphite continues.

 

To me it seems that only cooling can have a great effect on structures like these.

Here you have an ingot with typical dendritical segregation of cementite. The second picture is that same ingotremolten and given a `furnace cool`of +- 30minutes from 1550 to 1200 degrees celcius. this remelting was done in a SiC crucible, so that may have a great effect as well.

It could be that this graphite changes equally fast back to cementite when roasted an forged, who knows...

 

ingotC20X.jpg

 

monster220X.jpg

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Klaas Hi.

 

Here you have an ingot with typical dendritical segregation of cementite

 

I think this is not dentritical segregation...The pic actually dosent show any dentirites in it...but shows how

the cementite is formed..I think this stucture is Winmanstätten cementite needels and they are formed by faster cooling rate.

If grain as in ingot has is large time for diffusion of C is too short and C will stay in side the grain.

 

The second picture is that same ingotremolten and given a `furnace cool`of +- 30minutes from 1550 to 1200 degrees celcius. this remelting was done in a SiC crucible, so that may have a great effect as well.

 

If SiC crucibles are bean used they will show crucible reaction the phenomen that will lower the C and boost up the Si in steel, have said this before I think. Higher the temp stronger the reaction is.--C down----Si up!

Si is one of "elements" that will promote graphitisation strongly.

 

I think gas bubbles in steel ingot are CO and IF they are not contact whit air..."open"

They will weld shut at initial state...at least what I have seen happen.

 

Niko

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Adam, it's "scale", black iron oxide.

 

Thanks Dmitry, I already improved the description.

 

This will be interesting maybe, movies from the work of the master bulat, Igor Pampuha

 

http://files.gamewor...1c.html?lang=en

http://files.gamewor...html%22?lang=en

http://files.gamewor...8n.html?lang=en

http://files.gamewor...93.html?lang=en

http://files.gamewor...93.html?lang=en

 

I plan in this week melt with Zaqro's method.

If there is the success, I will show the result.

 

---

Adam

Edited by Adski

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Hi Niko

 

You are right about the needles. They form if you have more than 1.3% C (According to my book) and fast cooling.

On this photo you can see the dendritical segregation of the cementite more clearly (it's the same ingot):

 

ingotC5X.jpg

 

 

Klaas Hi.

 

 

 

I think this is not dentritical segregation...The pic actually dosent show any dentirites in it...but shows how

the cementite is formed..I think this stucture is Winmanstätten cementite needels and they are formed by faster cooling rate.

If grain as in ingot has is large time for diffusion of C is too short and C will stay in side the grain.

 

 

 

If SiC crucibles are bean used they will show crucible reaction the phenomen that will lower the C and boost up the Si in steel, have said this before I think. Higher the temp stronger the reaction is.--C down----Si up!

Si is one of "elements" that will promote graphitisation strongly.

 

I think gas bubbles in steel ingot are CO and IF they are not contact whit air..."open"

They will weld shut at initial state...at least what I have seen happen.

 

Niko

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Hi

 

My melting with Zaqro's method.

Small cake 320g. The iron from cut up nails.

 

 

dsc00046fy.jpg

 

dsc00047ra.jpg

 

dsc00050jm.jpg

 

---

Adam

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Hi

 

My melting with Zaqro's method.

Small cake 320g. The iron from cut up nails.

 

 

---

Adam

 

Adam,

Very nice and for a first attempt at that. I assume that is a high alumina concrete crucible in use. Thanks for sharing the experiment with us.

 

Jan

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Adam, nice ingot! is that a gasfired furnace you use?

 

Have you roasted that ingot? or was it still quite (red) hot when you removed the glass? I ask because I never have that black surface, unless there was too few glass in the crucible to protect the steel from making contact with the charcoal.

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Hi Klaas

 

i have seen similar problem in one of my bars.. long drawn out black spots ! i'm not sure what to make of it as graphite is usually more round nodules ( at least examples that i could think of ... so i maybe wrong ??)

-it could be inclusions like Dmitry says

- or also, i've read that if micro-porosity isn't closed in initial reduction of ingot, that these will become nucleation sites for graphite (as was mentioned)

 

one study on "graphitization of high carb steels " says that 1095 that is cold rolled (50%) can produce graphite when annealed at 560-680 cel.. around 25hrs.. it became easier to make when the steel was in stressed state

-apparently the carbides decompose into graphite and ferrite under long hold time... and the higher the carb level, the shorter the hold time needed to produce the graphite

 

 

Hi Adski

 

very nice ingot, that turned out very well

Good luck on forging and thank you for sharing !

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My melting with Zaqro's method.

Small cake 320g. The iron from cut up nails.

 

It should be good, looks good to me anyway. Good luck with forging.

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Jan

I do not know composition of concrete

 

Klaas

I use waste oil furnace. Yes ingot was still red.

 

Thank you, I'll be forging.

 

I clear the ingot...

 

dsc00052l.th.jpg dsc00051cn.th.jpg

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Jan

I do not know composition of concrete

 

 

Adam,

High alumina cement mixed with an aggregate such as crushed fire brick becomes high alumina concrete.. Often called castable refractory.

 

Jan

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Hi

 

I forged ingot and Work went well, no cracks.

Ingot no preheated, immediately on the anvil.

Start a small hammer 1kg, then a 2,5kg hammer.

 

dsc00056ns.jpg

 

dsc00057t.jpg

 

dsc00059tc.jpg

 

dsc00060df.jpg

 

---

Adam

Edited by Adski

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Hi

 

I forged ingot and Work went well, no cracks.

Ingot no preheated, immediately on the anvil.

Start a small hammer 1kg, then a 2,5kg hammer.

---

Adam

 

Adam,

Very nice job. What made you decide not to roast ( or do you never roast )? Can you make a guess at how much carbon is there? I think the melting (duplication of method ) you did will give others the confidence to try it as well ( I will try it before leaving this thread).

I hope to remelt the bad ingot today and maybe get a little forging in as well.

Jan

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I to be roasting some cakes. But not all. I think this bar has above 1% carbon, maybe 1,5%

 

the spark

dsc00063yk.th.jpg

Edited by Adski

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Hi Adam

 

nice blade, good to see it forged out very well

- what do you think the non-pattern part of blade is... sometimes i see this show up on some of my blades.. could it be that some of parent charge did not completely melt ? .. in my experience, blade still is very good for knife

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Hi Greg

 

I also think that is not completely melt. Not melted metal be carburized , blade should be good.

I will do new crucibles and check once again. But longer about 2-2,5 hour of melting.

 

---

Adam

Edited by Adski

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I had similar pieces in blades, and Zaqro in his piece he made on the workshop. If your knife is thick enough you can easily grind it of.

Best way to prevent this is to grind a complete blade before it is thin and check-etch it...

Very nice knife you made, congrats!

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Klaas,

This photo shows where I am at the moment, I will not be able to forge for about two weeks...I am a little concerned about the forged sample because after 12 cycles there is Zero evidence of a pattern....that could be really good or really bad news. I will remelt the cut ingot and not try to forge it. The other ingot in the photo should be good . These are my first round bottom ingots, I have some crucibles made with flat bottoms and will try to use them up regardless.

 

Jan

 

Klaas,

This is a picture(s) of "transitions" or "pain" or "learning curves". We hope "learning curves" is part of the content. The pretty items shown above are now distressed and I should be sad...but they did ( will) provde a lot of information. One sample has a lot of large but well dispersed cementie, while the other is holding on to the grid pattern ( it needs more forging ) sorry about the lousy picture it was taken through a magnifying glass. My next set will be in my comfort zone as I need a little reassurance.

The top photo is a sample of cast iron from a recent melt ( pretty soon we will be casting jewelry).

 

Jan

 

 

 

 

 

 

 

Jan

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wow!! that cast is a beauty!!!

The pattern in your steel is nice... I wonder why you have all cracks. Are you forging with a power hammer? what kind of hammers? Maybe you could try a non-roasted inot, and see how that works with your forging techniques as well.

the picture trhough the magnifying glass is good! I like it, it gives a lot of information! Maybe more forging gives tou more alignment and thus more pattern?

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wow!! that cast is a beauty!!!

The pattern in your steel is nice... I wonder why you have all cracks. Are you forging with a power hammer? what kind of hammers? Maybe you could try a non-roasted inot, and see how that works with your forging techniques as well.

the picture trhough the magnifying glass is good! I like it, it gives a lot of information! Maybe more forging gives tou more alignment and thus more pattern?

 

 

I think roasting had a positive effect, I am not sure....once I get into a groove I will go back and forge an ingot after an hour or so at temperture.

The cracks on the sides are just from pushing it too hard on a 50 lb power hammer...the real cracking problem is created by the shrinkage cavity, these cracks grow internally and come out anywhere ) much later . . If one forges a shrinkage cavity closed and just keeps forging in 1 plane, the irregular internal surfaces sort of nest into each other and often you can just keep going. If you forge a cavity closed and then start forging in a different plane=trouble. Forging a domed ingot with a shrinkage cavity may also present a problem which we will have to learn to deal with.

Once I realize an ingot is "lost" I just like to push it somewhere and see if anything can be learned. I will make a new ingot tonight (I hope).

 

Jan

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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

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Jan.

 

I see you forge it side ways!

What you think...how the energy goes trough the ingot if you forge it like that?

I think muzzy zone acts as dummer...and thats why im not forging them side ways.

Find shrinkage cavity ingots ideal for donut tech,Im not saying its easy...nothing is easy in wootz.

Im just thinking...how much C do you think ingot has? guesstimate??

 

 

Ric.

 

Thats od?

 

Why do you think its not useful to remelt "bad" ingots?

I find this just opposite. You can use lots force ingots like these and forge it to the

bar...whit " issues" in it whit out any worries...cut it and but it back in crucible.

I find them melting easyer too..but they might need bit more C IF too much of C was not the "issue"

Trying to calculate C in any ingot...its just guesstimate, so its same after remelt---guesstimate if analysis is not used..and even so it has deviation anyways.

 

Niko

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Jan.

 

I see you forge it side ways!

What you think...how the energy goes trough the ingot if you forge it like that?

I think muzzy zone acts as dummer...and thats why im not forging them side ways.

Find shrinkage cavity ingots ideal for donut tech,Im not saying its easy...nothing is easy in wootz.

Im just thinking...how much C do you think ingot has? guesstimate??

 

Rick, Niko

 

Well I have just made some that belongs to the floor...it was my first try using a larger crucible..the crucible worked well but the glaze did not flow. The bigger crucibles are thicker, more insulating and porous I guess ...in any case I should have let it go for another hr. at 2500F.

The ingot is all gassy and had a huge bubble in the metal .

I have materials for one more and then I am out for a while..( or remelt what I have ) .

 

I do not know the carbon content but if I can develop a clear pattern I will have it tested...I shoot for 1.5%C but it seems to take a lot of grinding to remove that decarb layer........? is that a decarb layer I am grinding, or did I have unmixed material in my melt? In that case the carbon may be quite high. I am just beginning to encounter the shrinkage cavity as an obstacle and will give you my thoughts after a few more.

Jan

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As promised new pics from a new sample of my large bar of bulat. This is the same steel as the macrophoto's in post #91, and the same as the pics I posted with the graphite.

This sample was taken from the other end of the bar, which never got 'too' hot (always forged at orange)

monster3goed5X.jpg

monster3goed10X.jpg

monster3goed50X.jpg

 

If compared to the pics I made of samples in earlier stage, I conclude that the following has happened;

- The blocky cementite is broken up more and getting more spheriodised

- cementite is more closely packed

- The banding is more linear

- The space between the bands is smaller

 

any thoughts are welcome!

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