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Dmitry.M

From ingot to the trash

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nice pictures ...

 

Dmitry your crucibles are fantastic..... specially being able to hold up to the punishment an oil furnace deals out..

 

does the outside of the crucible develop a glaze of sorts..? and can you pull out this kind of crucible while its hot... or is the clay still soft ?

 

Greg

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Greg, I pulled the crucible out several times and it was relatively hard, not soft. The clay mix I use does not glaze up on the exterior side, it remains rought and "dry". That might be one of the problems that I have with the oxidation. The crucible does not seal itself in the fire.

I tried to poke the crucible while it is in the hottes condition with the steel rod. it is not soft. A bit "tacky" but solid.

 

Again, that is my mix and it might be not the best and most likely it is not. But as far as I bought few bags of the components and do not have money to buy something other, I use what I have. So far I found that bigget crucibles with thicker walls work better, do not crack and produce better ingots comparing to the small crucibles.

later I hope to play with different clays and improve the quality.

 

As I foresee the question about my furnace... I bought the Colin Peck's book where hedescribes in detailes his steel and iron melting furnace. Mine is pretty close replica of his furnace. A bit different valve, different blower, but the main idea and size are very close.

Here is the link to Colins webpage: http://www.artfulbodgermetalcasting.com/

Edited by Dmitry.M

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Hi Dmitry,

Have bought the book and assembled the parts for the furnace need the time to build it now. What is your mix I have the gingery book on making crucibles, and his mix is 38% Fireclay, 2% Potash Feldspa, and 60% 20 mesh Brick Grog. Ant guesses to haw it may perform?

 

Thanks

 

John

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John, it may work. It will depend on what the fireclay is exactly. There are different types and names.

My mix is described here:

http://www.bladesmithsforum.com/index.php?showtopic=9608

 

I never used a feldspar and do not know what and how it does. Sorry.

You have to try and try and try anyway. Untill you will get right crucible. In my case the density is a critical piont. Actually everything is critical... that's what I found.

Edited by Dmitry.M

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Some fresh news.

I did not have much time, but managed to forge the ingot to the "puck" shape and cut it.

Here are the pictures of the forged piece:

IMG_2948.JPG

IMG_2949.JPG

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The size on the pictures looks not very accurate. The puck was 1" thick and 3" in diameter.

After I cut it I etched it in ferric chloride for few seconds to show you the pattern. There is a very distinctive decarburized rim on the ingot. This is the "shell" of mild steel that have losed it's carbon during the annealing. The dendrites are not very pronounced as the ingot was annealed, but still have the pattern and the shape. They would look pretty much the same in the fresh ingot, but with more detailed lines.

 

Enjoy:

2.jpg

Edited by Dmitry.M

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Hi Dmitry

 

woooooow that is a great picture .... you can see the mild decarb rim so clearly... and it doesn't look like the decarb shows any pattern...

 

 

off topic abit... awhile back i started giving my blades a lite clay wash to keep decarb down during heat treat... and i noticed better detail..... but that just maybe because my forge is running abit lean..

 

 

Greg

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Hi Dmitry!

 

That looks great! :lol:

 

:blink: The decarburized rim is showing so clear...how long did you anneal..did you used just over non magnetig temp.

 

Dmitry, i just notiset that ingot shows two different colours in decarb zone...darker (outer) and bit briter next..what you think it is---just decarb, but less than surface?

 

 

Great work.

 

Niko

Edited by Niko Hynninen

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Niko, thank you for the reply.

I do not know why it is the light rim under the dark one. It might be an artifact of my camera or of picture resizing. I did not mention it with my naked eye. The dark rim was very clear and visible.

I have to admitt, that the picture became a bit worse after few seconds. It was VERY clear and MUCH more detailed right after the etch. So next time I will etch and have my camera ready to make a pic right away.

 

It was quite interesting to look at the steel under the microscope. Unfortunately I can not make pictures. But I'll try to describe it...

Imagine the grainy structure that looks like a distorted stone(brick) wall. There are grains of similar size surrounded with the different material like the cement surrounds the bricks or stones in the wall.

The "stones" were a bit more grey, the "cement" was very bright and the etch did not touch it even slightly.

From this I made a conclusion, that the steel consist from perlite grains, surrounded with the cementite. This is NOT the best structure for the blade. It means I have too much carbon in it and the cementite could not be converted into the separate particles as it has to be in the wootz(IMHO). It is too much cementite there.

It also means that it can not be forged normally. The cementite is very hard and brittle. And there is not much of a "soft" matter to allow the steel to flow under the hammer and to make it tough.

 

I can say that for sure now as i forged the ingot into the billet shape. It was extremly hard at the very beggining and it is VERY prone to cracking now.

So far one half has cracked into two. So I have two "quarters" and one "half". The steel is starting to crack from the sharp edge. We saw the decarburaized rim in the ingot, but even this can not hold the steel from cracking.

 

From my perspective I would prefer to have the cementite grains or clusters surrounded with the perlite as a good sturcture to forge. I am talking about the annealed ingot structure.

 

If this ingot will be not "forgeble" I'll try to remelt it and add more mild steel to dilute it and drop the carbon content a bit lower.

later today I'll make few pictures of the billets.

 

Greg, thanks for the helpful info. I use electrical "muffle" furnace for the forging. When I forge(not anneal) the steel oxidized much faster than it decarburize, wich means this rim will be gone in the form of the scale. Very tight neighbourhood, can't run the normal charcoal or gas forge... and have to choose the right time when my neighbours go somewhere... :rolleyes: so they will not hear my anvil...

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Frogot to answer about the annealing time. I brought it to 1100C and left to cool down with the furnace... it took 10-12 hours to get to the room temperature.

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Hi Dmitry.

 

Thank you.

 

About mircoskope...i shoot pic trough eyepiece whit macro adjustment...and

use skope ( focus) to make image nice sharp....cam it self ( auto focus) dosent want to do that??Have you tryed this?

 

Too much sementite...so was there too much Carbon in resepy...about 2% :(

Wow...i sure hope you can forge it in shape...and it hold´s it form after HT also. :)

 

 

Niko

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Niko, I have SLR camera.... it's not that easy to trick it with the nonbrand lens. I tried to make pictures with it, no good.

May be for my records I need to get cheap "USB microscope". it does up to X400 magnification and takes pictures in .jpg

lokks like a toy but enough for taking pictures I quess.

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Frogot to answer about the annealing time. I brought it to 1100C and left to cool down with the furnace... it took 10-12 hours to get to the room temperature.

 

"Imagine the grainy structure that looks like a distorted stone(brick) wall. There are grains of similar size surrounded with the different material like the cement surrounds the bricks or stones in the wall.

The "stones" were a bit more grey, the "cement" was very bright and the etch did not touch it even slightly.

From this I made a conclusion, that the steel consist from perlite grains, surrounded with the cementite. This is NOT the best structure for the blade. It means I have too much carbon in it and the cementite could not be converted into the separate particles as it has to be in the wootz(IMHO). It is too much cementite there.

It also means that it can not be forged normally. The cementite is very hard and brittle. And there is not much of a "soft" matter to allow the steel to flow under the hammer and to make it tough."

 

Dmitry,

 

I don't know what (IMHO) means, please explain. I have seen this structure as described above and the carbon content was very high. The sample forged without cracking but never really became soft. My etch (after annealing) indicated the dendritic structure was not visible only a granular structure. I have thought about doing a test (experiment) next time I melt some cakes...cut and etch the as cast cake, anneal and etch the cake...then take the cake through a series of cycles and see if the dendritic structure will reappear. This should clear up any doubt the non banding thinkers have i.e. "the master".

By the way I did get this high carbon sample of wootz to crack, finally, (by beating on it while it was cold for a long time) but even then not all of it cracked.

 

In the process of downsizing my shop right now, but not the capability to play with some Wootz and Tamahagane, I will be joining you soon.

Jan

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Jan, it is very simple abbreviation.

IMHO - In My Humble Opinion...

AFAIK - as fas as I know...

BTW - by the way...

etc. :rolleyes:

 

I am not saying that my billets are cracking all the way in all places. But they are prone to crack. It might be because of wrong temperature, and how i suppose to know the right one???? :wacko: if I do not kow the carbon content or possible fact of contamination...

 

if you read the Virhoeven's articles you should know that it is impossible to rebuild the dendritic pattern after the anneal. it is a function of first ingot crystallization. You may configure the grains close to the former dendritic pattern if you did not forge it much. Otherwise you will have very much distorted pattern and in many cases it will be far from original one. I think so...

The "master" is not the dendritic pattern itself(at least not always). You can produce the master during the annealing-forging for the cementite deposition. This "master" could be made different ways. In some cases it will use denritic pattern or even dendrites themself. in some cases nothing will resemble the former dendritic structure. that's what I found from my experience.

If there would not be so many problems and traps on every step of wootzmaking... :wacko: One mistake can spoil the steel and you never would know for sure where and how it was spoiled...

 

P.S. I thought we only expand our shops...

Edited by Dmitry.M

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if you read the Virhoeven's articles you should know that it is impossible to rebuild the dendritic pattern after the anneal. it is a function of first ingot crystallization. You may configure the grains close to the former dendritic pattern if you did not forge it much. Otherwise you will have very much distorted pattern and in many cases it will be far from original one. I think so...

 

Dmitry,

 

Thanks for the lesson in abreviations. I agree the original dendritic pattern will not return exactly but the carbide formers "the master" are in location and the spheroidizing cycling should create a pattern clearly associated with the original one (prior to annealing). I have started forging (and dropping/picking up) an ingot not annealed... it is moving ever so slowly and the dendritic structure is still visible. I thought I would give this a try because Massalski is unclear as to what happens to cakes after testing...what if a cake passes the test prior to annealing? I will start to bring up the temperature a little but keep it at a minimum and keep an eye on the structure as I progress.. Yes shops tend to expand, but mine is an exception...I know what I enjoy doing and don't want the clutter and distractions of "stuff" in my space anymore.

 

Jan

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the carbide formers "the master" are in location and the spheroidizing cycling should create a pattern clearly associated with the original one (prior to annealing). Jan

There is a catch... those carbide formers could be very different..... some of them are pushed out of dendrites at the first crystallisation in the ingot. Some of them may be dissolved in austenite, some of them may be in any place. Some of them very easy to move during anneal, some ov them impossible to move with the anneal... The efficiency of different initiaters is different.

I agree, that in general the grain should resemble the original dendritic pattern.... funny, but this 'should" never worked for me... :rolleyes:

 

OK. Here are few pictures of my billets. No grooming, no editing. Just plain pictures "as is".

Brocken one:

IMG_2953.JPG

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Both halves, view " from inside the cut ingot" :rolleyes: and from the former top of the ingot:

IMG_2954.JPG

IMG_2955.JPG

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There is a catch... those carbide formers could be very different..... some of them are pushed out of dendrites at the first crystallisation in the ingot. Some of them may be dissolved in austenite, some of them may be in any place. Some of them very easy to move during anneal, some ov them impossible to move with the anneal... The efficiency of different initiaters is different.

I agree, that in general the grain should resemble the original dendritic pattern.... funny, but this 'should" never worked for me...

Dmitry,

Good luck forging the remainder of that steel. Is your hammer textured or are those grinder marks? I am getting depressed thinking of all those bad carbide formers getting out of line and assume that if a forged piece of wootz has very distinct bands of spheroidal carbides, some of what you state is possible, did not happen. So we will have to operate under conditions where these guys do behave. One question which fascinates me is what is the mechanism at the sites of these carbide formers (some good Winter reading).

 

Jan

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Jan, if I would know that.... My guess is that the one who managed to get descent pattern and godd steel quality made it in more like an accident rather than a well planned and predicted process. But do not worry about this. You may be lucky and will get the right result in the first attempt. :lol:

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About the hammer... it is a regular 4-pounder form the hardware store. Nothing fancy at all. And the tracks are the traces of the lathe cutter left on the hammer.

Edited by Dmitry.M

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Hi Dmitry .

 

:( thats very unfortunet setback.

 

Dmitry have you anyway notiset douring forging cycles this lower temp superblastic behavior?

IF im not totally wrong Heating over and under critical...+ forging enhances the grain structure...and if grain is small( really fine)...this phenomenom can be notiset low tep...+ 700-800C

 

In my 5 run i heat 1/2 ingot non mag let it cool back to mag....repeat this at least 10 times + several times douring forgin...steel can be ( even ultra hi carbon) blastic even low temp. ( i notised this in my 5 ingot)

 

SO .... if we enhance grain of crucible steel.....can we dissolve "wootz like " structure away??

 

I hope NOT!!!!

 

Niko

 

I sure hope all understands my writing :huh:

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Hi Dmitry .

 

:( thats very unfortunet setback.

 

 

I sure hope all understands my writing :huh:

I can understand you pretty well. Do not worry. :rolleyes:

It is not a setback, I am going to forge this ingot to the very final stage. It might go bad and will end up in the trash again. Or not... I want to learn as much as I can. Every ingot, every blade is different.

 

I did not mention any superplastisity in my ingorts. May be the low carbon ones were softer and did not crack at all. But in general all of them were pretty stiff.

On the other hand, ones you forged the ingot to the small billet and disturbed the structure enough, the steel becomes more maleable, viscous. And yes, it can be forged at low temps than. But it happens every time.

Can I make the ingot superplastic with the multiple anneals? May be, but do not know for sure...

May be next time, next ingot...

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Hi Dmitry

 

 

 

 

Maby i wrote it wrong...superplastisity i ment in general....consernig any of ingot´s that you have all ready made.

So not this one just...

Superblastic phenomenom is link´d in wootz steel in many articles that i have found..and all of them mention C level to be hi or ultrahi...

Even this study of "one hit" shape chance at quite low temp + 800 speeks same.

 

I was just thinking..if we can make ingot superblastic....do we have to forge all those 50-200 cycles.....just to greate "typical" pattern in steel.

If same pattern can be obtain one single blow......yes i know it should be BIG powerhammer...but it makes intesting idea..

 

Dmitry.....i disint want to mess up your topic....and im sorry if i did that whit this post....area of crucible steel is narrow here....and this, that i have to think my text first in Fin....when i think i get it....Trans it to eng....so it´s not easy...to be me :mellow:

 

Take care :)

 

Niko

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Update.

All billets are cracked and no good. Here is the picture of the remains of the smallest one. i decided to go to the end with it and tried to takeit down to the flat piece. No chance... It started to crack when it was 3/4" square. The biggest piece(one half) is at the same point now and it started to crack the same damn way. At the end it looked like the billet simply felt apart. Jeff was right, there is some limit in the deformation at wich the steel can not stretch anymore.

So this ingot is proudly added to the trash pile.

I tried to make a picture of the ground and etched steel. No success. It is simplier to describe in words. The structure is still the "mesh" Like a chicken wire just less regular. the size of one cell is 0.1-0.2mm maximum. I think it is less. The middle is slightly etched and darker than the rim. The grain rim is solid and bright. There is very distinctive dark rim of mild iron that covers the billet. It is etching almost black comparing to the inner material.

 

Why it is happening again? I thought it might be a iron oxide that makes hot shot. this time it should not be there but the billet failed the same way. It may be a sulfur in the steel from the graphite... need to try different source of carbon. What else? Do not know. Hopefully this weekend I will make another ingot... for the trash.

IMG_2957.JPG

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