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Jan Ysselstein

In Search of Hamon, Experiments at the Forge #1

113 posts in this topic

The above bars were reworked,

Bar showing pattern ( wootz/wrought) was split down the middle and each half was widened a bit.

The crucible bits bar showing no pattern and no carbon contrast (?) was folded a few more times ( lost some material but should get 1 quench out of it). I am losing some material because I am forge welding all handles to the bars.

The plan is to finish the thread with the high carbon bloom material ..have some decent hamon and Exit...I am still working with clay as a flux and hope to will finish that as well.

Edit,

The clay/straw ash  welding process  worked  ..I was able to weld a file back on itself( after modifying the clay several times ). This is turning out to be a very interesting process and at some point I will do a bar using only this process..at this point it served more as an understanding tool. Variables are not just related to the clay.

Jan

Edited by Jan Ysselstein

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I have started the refining and welding of high carbon bloomery iron and will try to do about 12 folds before shaping the remaining steel into a tanto. The welding of the first bar with straw ash as flux worked pretty well . Here is a picture of that first bar before  doing any folding. The welded bar still sparks as high carbon.

DSCN6125.jpgconsolidated bloomery iron

Edited by Jan Ysselstein

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I have been processing ( consolidating ) some high carbon bloom into bar stock and need to reduce it to wafers before moving on. The bar stock folding will result in a blurry steel color , which I want to avoid. For now I will stop and build another furnace as the exterior shell is turning yellow during the welding process. Here are a couple of pics.

A bar cut and broken ( that is a slag burn on the hand ), flattened consolidated bar quenched and broken ( I am still looking for the ones that flew away)

The cut bar break was hit with a rotary wire brush.

DSCN6138.jpg

Consolidated ( flattened ) high carbon bloom.

DSCN6139.jpg

Edited by Jan Ysselstein

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I have to take advantage of the seasons here and open fires are not allowed after April 30. Rice straw ash is becoming an essential ingredient in the welding of iron ...today I converted a bale of straw to ash.

 

Edit:

The yield of this run if expressed at % of ore weight was 47% 

The yield if expressed as total iron added    was 65%

All metal, slag and fluff was recovered and will be recycled as "ore" the cooled charcoal is ready for reuse as well. Next time we will try for a high carbon bloom... .

Cast iron bloom with viscous slag layer on top

DSCN6184 (1).jpg

Bloom profile showing bottom of furnace shape

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Bottom of the bloom, very little entrapped charcoal

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Slag and trapped  cast iron..most of the cast iron was in the shape of smaller prils 

 

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It took a while for me to figure out how to reduce the smoke

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Amazing material having so many uses..I form it into a powder..while in use it continues to burn and becomes a true ash. I have not noticed the benefit associated with having the carbon in the charred straw ..so I use the ash as well as the charred straw.

 

IMG_3465.jpg

! bale makes about 25 gallons of ash and will last several years..age and the absorption of humidity seems to make no difference

 

IMG_3466.jpg

Edited by Jan Ysselstein
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Looking very much forward to this

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Jan, typically rice straw ash is used. It is suspected it is used because of its high silica content, up near 90% silica after it becomes ash. This silica is not present in other straws, as I suspect the minerals are absorbed into the straw due to it growing in partial flooded water.

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Thank you Daniel...I have done lots of tests with that material...amazing stuff.

The cast iron bloom in the post above will be repeated in the next two days. I will try to shift some variables to get closer to the goal of making an easily reproducible high carbon bloom. So 30  lbs of ore is ready and 1.5 hrs of run time should give us rate of .33 lbs per minute. Though that is good clip, I have done over 60 lbs per minute in previous runs.

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Jan, could you post a pic or two of your furnace? I think you said you were building some new forges/furnaces etc.

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Joshua,

   I have some pictures of a forge build very safe  and very hot.......I will post them in a day or so. I have a video of how it works but I do not know how to post it. When I choose it from my desktop all it does is show the file name.

 

Edited by Jan Ysselstein

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Got the chance to run another furnace last week and the iron looks good but the yield is low.I am using old charcoal and got into some pretty small material and ashy material. This is one of my attempts at adding slag to the mix..the charcoal got me into trouble....  

I will use this bloom ( very high carbon , very bright but no colors ) in the next few posts here to see if I can fold it.

Bottom of the flat bloom and a foaming slag mass found on top of the bloom 

IMG_3025.jpg

 

Foaming slag, showing small charcoal

IMG_3040.jpg

 

Broken bloom 

IMG_3047 (1).jpgIMG_3043.jpg

Edited by Jan Ysselstein
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Curious about the carbon content of the above shiny bloom. Here are some pics after a rough grind..not quite cast iron but way up there..my guess is close to 2.% carbon. I will try to forge it after a long 2 hr soak in slag ( the foamy slag shown above + a little borax) .frame5.jpg

Edited by Jan Ysselstein
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Soaking the above flat high carbon bloom for almost 2 hrs , occasionally adding borax, worked ..I tested a section and was able to compact it vertically but it has no strength side to side...it should stack and come together.  My new forge/crucible furnace is done ( very simple ) and I hope to weld some more this week end. The bubbles forming under the borax are carbon monoxide ( CO ). If my metal sample were to weigh 500 grams and be at 2.4 % Carbon and I wanted to reduce that carbon to 1.2% Carbon...then I would have to lower the carbon by 6 grams. The volume of CO generated by 6 grams of carbon would be about 3 gallons of CO at room temperature  ( patience). Adjusting for temperature difference at the forge temperature that would be almost 5X as much in volume.

 I have made some charcoal ( Pit Charcoal ) , about 275 gallons and due to my fear of small particles I will probably only be able to use 1/2 of that material. 

Edited by Jan Ysselstein
additional info.
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IMG_3609.JPGIMG_3609.JPGIMG_3611.JPGI liked the last bloom material in the previous post ( it has potential and is very easy to process as a bloom ) so I attempted to make some more. That is it for me this year lots of oroshigane coming up on older blooms. Here are a couple of pics of the last bloom which is just a shade lower in carbon than the one shown above.

IMG_3608.JPG

I don't know why the text moved on me but it is up there somewhere

Edited by Jan Ysselstein

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So, taking a look at the microstructure , I think we have too much carbon...but going directly into a crucible as wootz may work. I will try to weld this material after decarb. treatment. I will test some clay welding slurries this week end..

frame6.jpg

 

Edited by Jan Ysselstein

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"The use of just clay was also tried today and needs more experimentation. The clay ( once dried over the furnace exhaust ) stayed in place and stayed rigid...we will get back to this even if only as a protection against carbon loss."

"Clay will require me to cool the material quite a bit ( for it to stick and then get dried ) and will slow the welding process."

      " Actually  "The time of reckoning. Cool."   is now, as now I am at the stage of having to weld and refine the bloom material. I think I am dome practicing and am ready to go. I will post some pics of the high carbon material and hope for the best. Some of the lesson come from the Japanese guys ( all the books and videos) and some from the old shear steel makers. The plan is to finish the thread with the high carbon bloom material ..have some decent hamon and Exit...I am still working with clay as a flux and hope to will finish that as well."

 

 

Today

I think I have figured out the Japanese clay/ash welding process ( took a lot longer than I thought it would ) I will grind a bevel on the sample and picture it ( 4 consecutive clay/ash forge welds). Things are falling into place..that steel in the above post is a little too high in carbon but I will try to make it work. Hoping to close this thread soon.

 

Edited by Jan Ysselstein

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The bevel grind on the sample discussed in the above post showed some very thin dark continuous  lines. This encouraged me to practice some more welds, shifting the process to remove the lines. In the process I learned a new Japanese word       "Wakibana"  little white sparks.        When forge welding in coal, coke or charcoal these are very familiar...but in a gas forge ..better turn off the lights and pay attention. Here are a couple of pics of rusty file , cleaned and forge welded back on itself 3 times. ( you are looking at the thin cross section. The lower two pictures show the dark lines at the clay/ash welds of a previously folded piece of bloomery iron.

My thinking about this part of the process is constantly being modified   , sometimes I see videos of a very casual application of the clay/ash mixture..sometimes very deliberate. When done carefully this is an amazing way to not lose carbon....very effective.

 

Next steps  ..find the best "tamahagane I have made so far..practice one more day with bloomery material and go for the tango shown in one of the posts above ( I seem to not be able to find the number of the individual posts any more..(administrator , could that be fixed?) 

 

Wakibana1.jpg

wakibana2.jpg

practice 1.jpg

practice 2.jpg

Edited by Jan Ysselstein

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Very interesting, Jan!  As for the post numbers I have no idea.  I don't see them on my phone, and the desktop pc is not handy to see if they show up there, sorry.

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I have taken all the stuff sitting around from various bloom sources ( cleaning up ) and started welding them together. The mud/ash process is becoming more familiar, though I do see some captured slag as a dark line. ( this welding method can be used for a carbon content up to about 1.3 % Carbon).  The metal temperature is taken to over 1300 C ...high enough to melt very high carbon iron. Basically when you think the weld is ready, the stiff remnants of the clay/silica are nocked off with a scraper , the hot fluxed metal is touched to a pile of straw ash ( the bottom that is ) and the weld is set. Quite amazing really.  When all is routine I will take a video of the process to clarify the basic steps.

 

On the same sample I also tried a couple of welds using just slag and quickly found myself in unfamiliar territory..I did set the welds ( the captured slag mentioned above may in fact be from this test). More time is needed here  to play with the sequencing and timing of slag addition. 

The disadvantage of the welding methods is the danger when forging under the hammer..the metal becomes very slippery and difficult to hold in the tongs.

There are quite a few inclusions....I will start planning for a cleaner work surface as soon as I get the slag method down. Here are some pics. the metal looks very solid and clean to the naked eye. I may be imagining it but ..in the large picture the decarb just under the scale is not as bright white as what I am familiar with...maybe.

I will draw it out and try to quench it.

frame1.jpg

frame2 2.jpg

frame3.jpg

IMG_3162.jpg

Edited by Jan Ysselstein

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By preparing for a clay coat I thought I would take a few more pictures after grinding off most of the scale. There are some bad welds here and there, might be due to some problems way back in the thread. The bright areas on the right may be some low carbon material in the mix. I find the color contrast interesting .

IMG_3168.jpg

IMG_3166.jpg

IMG_3166 (1).jpg

IMG_3164.jpg

Edited by Jan Ysselstein
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,I made some cast iron on Sunday and who knows what today. I will take some pictures of the materials made  ( the cast iron is already crushed )..what ever it is, it was dramatic..runs never go that smoothly. I will have some time this Friday to weld up some high carbon bloomery material using the ash/mud method. I hope to exit here in a few days.

Jan

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Yesterday's run was interesting..the two runs shown below in a pan represent all the combinations I am seeking. Cast iron is shown ( Sunday's run) as broken pieces, the bloom  (yesterday's run)  is very solid ...the top is very very soft iron and the broken area at the bottom of the bloom is very high carbon...Fascinating. Here are some pics..closing this thread soon. The yield approached 50% clean bloom to ore ratio and 69% of the iron added was recovered. That is an approximation as I do not weigh the ore ..I just keep adding 1 lbs. scoop every 5 minutes...and 3x the amount of charcoal each time. The clean bloom weighed 16 lbs and the cleaned cast iron weighed 13 lbs. .

 

IMG_3234.jpg

Bottom of the bloom siting on cast iron bits

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Bloom, showing the oxidation colors at the high carbon area

 

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Bloom sitting on cast iron bits

IMG_3247.jpg

Cast iron bits

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Cast iron bits

IMG_3260.jpg

 Everything in the pan

Edited by Jan Ysselstein

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There coke furnace is ready for some crucible melts , it is just a bottom blown coke forge.. I will be taking some of the materials  in the post above..crushing the cast iron to make sure it is clean, small ( no slag) and mixing it with low carbon iron ( bloomery iron ). To get a complete melt I may have to go to 1500 C ( see the iron/carbon phase diagram ) but I am not sure I need a complete melt in this case. The crucible will be sealed with a weakness in the seal somewhere ( 2 of them , pour and vent )..so I may pour out the contents to create some 3/16"+   plate. We are shooting for about 25" square at 3/16" thick at about 750 grams.

Edited by Jan Ysselstein

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The homemade crucible failed ( very common ) , I am am not sure nit it was from the inside or the outside....bummer. Not a good day in the shop. I need to make some modifications to the furnace to keep the heat where I want it..I have some pics and will add them later.

Here are some pics.IMG_3883.jpgIMG_3885.jpgIMG_3884.jpg

Edited by Jan Ysselstein

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The plan was, to cast the molten steel ( iron? ) into the cast iron pan..decarb the surface severely,soak in a neutral atmosphere, quench it and break it. I did pour a little of what was melted in the failing crucible onto the cast iron surface ..that should work well. Not having a sealed crucible is not good when the crucibles are as porous as mine are. So I will work with a sealed crucible and somehow open it at pouring time.

The high carbon bloom is ready to weld ( we are in a heat wave and I am not going to the forge ) ..I will be welding up some low carbon iron to test out some traditional welding methods where carbon loss is no issue. 

Edited by Jan Ysselstein

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Here are some samples of traditional welding of low carbon modern steel. the welds are almost parallel to the surface of the samples. The first weld is shown at the upper right of the first picture, notice the residual iron oxide in the weld zone. The second weld was made after carburizing the sample a bit , it is shown in the remaining images. All, if there was any,  carbon is gone and the weld looks like two channels next to each other...that I assume is the result of the chemistry of the weld. I should have etched to make sure there was some carbon before the second weld. Next time. The fact there was less iron oxide in the second weld is circumstantial evidence there was some carbon.

frame1.jpg

frame3.jpg

frame5.jpg

frame8.jpg

Edited by Jan Ysselstein

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