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Here,I am jumping from the "Pit Charcoal" thread ( http://www.bladesmithsforum.com/index.php?showtopic=28695 ) to one specifically dealing with crucible steel. I have dragged some of the already posted material into this place just to keep it together.

 

I don't know how many of you have attempted this Georgian 'Bulat' technology by Zaqro Nonikashvili
method of making Wootz...I highly recommend it, and see it as the clearest method on the web to date ( I am very grateful for Zaqro's contribution and to Klaas for bringing it to us) . This year ( 2015 ) I hope to attempt it again using the 'Konasamudram' process as alluded to here http://www.bladesmit...=18364&p=172409 . I think I have the melting process down ( I sure hope so ) and plan to begin experimenting with the process of forging.
Right now I am healing a sore shoulder but should be able to go on light duty in a week or so, melting iron is light duty.

 

Two crucibles are loaded ( 1 Kg charge each) , for a test ( mainly to see if the glaze is still good).....once I get back into the melting mode I will try a larger crucible. Larger crucibles have a vey large failure rate.

So it will be a while before I get ready to try 'Konasamudram'....bear with me.

The first of two crucibles was melted today..15 min. warm-up and 45 minutes to melt. I used my forge to do the melting and I will have to redo it . A new thread will now be started to go with the crucible steel..I will leave the bloomery stuff here ( here is under Pit Charcoal").

I will post some pics of bloom results and the ingot soon ( after it cools).

Jan

Edit

The ingot is 1002 grams and has a decarburized top , no glass was added...the glaze was not totally effective as an oxygen barier. I will drill a hole into the second sealed crucible and add some glass prior to melting this week-end. Due to the forge being used as a heat source..the flame directly impinged on the crucible..I will try to avoid that on the next melt.

Here is the 1002 gram 'Konasamudram' process ingot #1. Lots of things are not right..most I created myself and will try to avoid next time..I can eliminate the bubbles under the top and the decarburization. Basically I am quite happy with the results..even if I end up cutting off the top 1/2" off the ingot.

The forging of the ingot will give us additional information for establishing directions in future melts ( until we get it just about right, I hope).

DSCN0377.jpg DSCN0376.jpg

Jan

Edited by Jan Ysselstein

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Hello Zeb,

 

I have left the crucible making topic out, intentionally. Primarily because the crucibles become like glass and I have a safety concern. I once tried to pick up a finished crucible and it fell apart in the furnace, it has been eaten away by the iron fluxing action on the wall..The other reasons are, they do not have to be homemade to produce good wootz and there are lots of formulas here and on the web one could use as a starting point. In retrospect I am not sure doing the homemade route was even worth the effort.

I learned to make crucibles fron Vassili Fursa ( could not open his old links for attachment ) I have seen great tutorials here by Skip Williams and Dimitry...Zaqro has a great formaula posted in his thread ( but one look and you know he is using a press). I have found all my crucibles porous and am attempting to develop glazes which will seal at high temps, I am getting close. Once my press is operating I will try Zaqro's formula type.

 

Here is a thread I participated in (2007) showing how long I have been at it ( http://www.swordforum.com/forums/showthread.php?75630-Clay-Crucibles-and-design-for-wootz-poulad ).

Jan

Edited by Jan Ysselstein

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The above ingot (KOS#1) has been cut into and is found to be free of holes or other major defects and seems to have been completely melted. I found is difficult to post (photograph) the etched image but I will post a photo of its brother a well studied Indian ingot from the British Museum. I will post a better image before forging.

Now I have to take all the information I have ( prior to forging) ( I am still on light duty ) and decide what to do with the next prepared crucible.

 

Face of cut ingot showing few if any defects

Kos#1.jpg

KOS#1b.jpg Lightly etched due to wrong etchant

SmithIngot.jpg Late 19th Century Indian ingot was in the Royal School of Mines, now in British Museum, KOS#1 looks just like this.(1.3 % C)

 

Jan

 

Should you want to be an arm chair wootz maker ( future wootz maker) , feel free to make observations or suggestions no matter how uncertain you might be about the topic ( you could save yourself a lot of time effort and money)..if I choose not to take the recommendation I will try to explain why. I do not really understand all this stuff, especially the process in the title.

 

Jan

 

 

 

Edited by Jan Ysselstein

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That looks wonderful my friend!!!!

Congrats!!

Now come the real fun. :)

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Thanks Mark,

 

I have replaced the etched picture with one slightly better. Yes , I agree forging is the fun part.

 

Jan

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The second crucible was melted today in the same old forge with the same flame impinging on the crucible ( I did glue an old chard onto the crucible to lower the impact of the flame).

I did not add glass..I am going to try to avoid glass for now ( while using the small crucibles ) because I will be doing some melts with carbon and my bloomery wrought iron.

 

The only concern I had really, was the holes on the sides..I just left it all in place for another 15 minutes of heat.

I will pull the crucible tonight or tomorrow.

A cooling rate number needs to be established for each trial...that is not just connecting two points as the rate of cooling will vary over time.

 

Jan

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Ingot #2 is very porous, almost as if the shrinkage cavity is spread throughout I will forge it and attempt to close some voids. I can imagine the ingot solidifying as a complete shell causing tearing throughout the ingot.

 

#2 will be repeated tomorrow....then off to a larger crucible and slightly larger ingots.

 

Jan

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Here is a picture of Ingot #2 ..I am actually OK with the results as the metal is uniform ( though torn) ...I should be able to close these holes. My guess is the outer shell cooled and the top solidified due to carbon loss before the core solidified. Had I used glass, the top would have remained liquid for a longer time period and shown a shrinkage cavity.

So I will keep melting until I get the OK to start forging..I should have about 6 cakes by then all of the same composition but not the same shape.

 

DSCN0433.jpg

 

Jan

Edited by Jan Ysselstein

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Last night Ingot #3 was melted ..it weighs 1198 grams and looks more like a doughnut than the previous ones. It has some porosity, seems forgeable and has its own sort of beauty. I will edit a picture into this post later.

 

KOS#3.jpg

Edited by Jan Ysselstein

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Way to go!!


How many heat cycles do you do on these before you start hammering on them?

I have never had much luck closing up the little voids. I'm sure that is mostly my inexperience. But the voids always seem to become cracks, that just will not ever "heal"
The last few crucible steels I made were much lower carbon. I wasn't shooting for wootzy stuff, just crucible steel I could forge. around .8 C. That worked out pretty well.

Of course I did drop my best woozy ingot into the water bucket! That didn't help much. ;)

Looking good Jan.

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Mark,

Just once normally , I usually work with low C cast iron cooled fairly rapidly. I hope the voids will weld on a press once the material is in a workable state. If they do not close I will have to learn how to avoid them. I am not sure my setup will melt .8% C with out a major meltdown of everything.

 

I have the next crucible all set up but need to patch the forge.

 

Jan

Edited by Jan Ysselstein

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Ingot #4 is not to be....about 10 minutes into the melt the sparks began and the crucible failed. The temperature ramp up may have been too steep, crucible had a thin area. I have another smaller crucible set up with 1000 grams iron and 25 grams carbon, sealed, no glass. I am overshooting the carbon by 7 grams..expecting some loss due to oxygen entering the crucibles

Tomorrow I will glaze it and try to replace the now ruined forge...if not possible, I will rig up a charcoal furnace. This test is an effort to gage the porosity of the crucibles.

Once I have 4 or more ingots I will start light forging.

Jan

Edited by Jan Ysselstein

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Hi Jan

 

Looks good, what charge did you use for this crucibles? Zaqro's technique? or did you use cast?

 

Good luck with the forging!

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Hello Klaas,

 

The charge used is 55% cast iron 45% wrought iron...my cast iron is about 3.3% carbon ( guessing based on previous runs ) so my target is 1.8% C ( this will be the charge for all trials unless noted) .

 

Today's run ( carbon and wrought only) is just a test of the crucible gas exchange..I am concerned about using my charcoal as it seems wasteful to put a single crucible into my charcoal fire and at some point the ash buildup has to be removed...I need a bottom door to pull some fuel out to drop the fire down a bit. Maybe I will get the forge fixed as a backup.

 

Jan

 

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Ingot #5 ( #4 did not work out ) is cooling in the furnace after 1 hr of heat ( this does not include the time required to bring the crucible up to heat ) ...the dip stick told me it was molten so I stopped and closed the furnace. Ingot #5 is made with carbon and wrought iron..no glass, no glaze, just a look at the crucible leakage.

 

Now that I fear the large crucibles again ....I will melt another smaller crucible of cast and wrought ( ingot#6 )...before going back to one larger one..then we will forge them all and finish the topic by doing the last one in charcoal.....

 

Jan

Edited by Jan Ysselstein

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#5 Ingot is not very pretty..not going to get forged..another 15 minute at heat and some glaze on the crucible would have helped. Now we are at two out of five and always optimistic about0 #X. By he way #6 is ready and GLAZED. Pretty soon I will be running out of easy to grab clean cast iron and the real work will start.

 

Jan

 

 

EDIT:

On second thought I will try forging this ingot #5 ( even a fragment of it) as it has an interesting appearance under a magnifying glass.

Jan

Edited by Jan Ysselstein

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Seven melts were attempted, one lost as a failed crucible and six to be forged , though none look ideal at this time. ..Let's see what some of this metal looks like.

Ingot 6 is much like #1 , #7 (large ingot) looks good but has a top sitting over a void of bubbles , the rest of it should be good/

 

 

I will post a photo of the group of ingots by editing this post.

 

Jan

Edited by Jan Ysselstein

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Well done Jan, it will be interresting to see how you go with forging the ingots. I find if you get the melt a little too hot you can have voids forming in the ingot like you have there, often they then fill with carbon, and so you have to forge them as high as possible to be able to close them. I would forge the ingot and get it soft before I try to close the voids or you risk not having them close or cracking the ingot.... I generally haven't had success in closing the voids, although I have heard some do have success on occasion. Hopefully you can make something workable from those ingots.

 

Don't rush the forging, the slower you go and the less force you use initially the better your result will be in my experience.

 

Sorry to hear about your forge, hopefully you can fix it, for first time forging of Wootz I find that it is better to use gas as you can control the atmosphere of the forge and the temperature much better.

 

Happy forging!!

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Tim,

Thanks for the suggestions , here is a pic of what I have so far ( from left to right 1,2,3,5,6,7) , The last 3 ingots have huge cavities under their cold tops ..it seems the problem got worse over time.. Ingot #5 sgould be ignored and not even be in the picture.

The crucibles really hate glass..so I do have lots of limitations.

Each ingot should have a small volume of good material worth the forging effort, then I can decide where to go from here.

I have done a bit of a cooling rate study to see how the cooling rate varies over time and what is a realistic cooling rate for a good product. I am also trying to come up with an ingot measurement giving some predictability of the pattern size ( assuming the same degree of ingot size reduction ).

 

It will be a couple of weeks before I have time to forge this stuff

 

photo-1.JPG

Edited by Jan Ysselstein

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Hi Jan

 

Nice collection of dinosaur eggs you have there :)

I always collect the glass/slag from the crucible and re-use it. It seems it is less agressive then!

Also I believe to have notices that a little bit of charcoal on top of the glass helps. Make sure you have enough glass/sand than, you don't want it to go with the iron/cast of coarse.

 

Good luck with the forging!

 

Klaas

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Thanks Klaas,

 

On the next series, I will be adding some low melting frit. I will try the piece of charcoal on top as an indicator of what is happening in the atmosphere above the ingot. Both the atmosphere and the ingot chemistry will react with the slag (glass). I am vey anxious to forge these or at least find out which are able to be forged and which are not..to the untrained eye right now only #1 looks questionable as it may have too much carbon.

 

Jan

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