Joining the madness...

[Jerrod Miller]

RFQ generally stands for "Request For Quote".  They may be quoting several tests to get really high accuracy across the board.  OES, Leco Carbon/Sulfur, gases, etc.  Getting just OES should certainly be much closer to $100.  Definitely is just over $100 at IMR, as I got that done there pretty recently.  

[Kreg Whitehead]

On 1/10/2021 at 2:59 PM, Bill Schmalhofer said:

I have been wanting to try a hearth furnace for several months now, but a leak in the master bathroom and the resulting repair work has had me occupied for a long time. Today I finally said I need eda mental health day and to do something fun. So hearth furnace run one. Did the (what seems to be becoming the ) standard 7 brick furnace with the blower from my first coal forge. Charged it with 5 - 200 gram charges of A36 that I had sitting around. Time between charges was about 5-6 minutes. Total recovery was about 800 grams.

 

Furnace before first charge.

 

Had two pieces come out. Here's the main one. Is about 770 grams.

 

Spark test of beginning material.

 

Spark test of furnace material. Same belt, same grinder speed, same pressure as the starting material picture. Any thoughts on carbon content? Also, as I was consolidating it after pulling out of the furnace, it seemed super solid. I was not able to move it much with a 4 pound hammer.

I may need to try this soon. Forgive my ignorance but what fuel is in the furnace....just hardwood?

On 1/10/2021 at 2:59 PM, Bill Schmalhofer said:

I have been wanting to try a hearth furnace for several months now, but a leak in the master bathroom and the resulting repair work has had me occupied for a long time. Today I finally said I need eda mental health day and to do something fun. So hearth furnace run one. Did the (what seems to be becoming the ) standard 7 brick furnace with the blower from my first coal forge. Charged it with 5 - 200 gram charges of A36 that I had sitting around. Time between charges was about 5-6 minutes. Total recovery was about 800 grams.

 

Furnace before first charge.

 

Had two pieces come out. Here's the main one. Is about 770 grams.

 

Spark test of beginning material.

 

Spark test of furnace material. Same belt, same grinder speed, same pressure as the starting material picture. Any thoughts on carbon content? Also, as I was consolidating it after pulling out of the furnace, it seemed super solid. I was not able to move it much with a 4 pound hammer.

I may need to try this soon. Forgive my ignorance but what fuel is in the furnace....just hardwood?

On 1/10/2021 at 2:59 PM, Bill Schmalhofer said:

I have been wanting to try a hearth furnace for several months now, but a leak in the master bathroom and the resulting repair work has had me occupied for a long time. Today I finally said I need eda mental health day and to do something fun. So hearth furnace run one. Did the (what seems to be becoming the ) standard 7 brick furnace with the blower from my first coal forge. Charged it with 5 - 200 gram charges of A36 that I had sitting around. Time between charges was about 5-6 minutes. Total recovery was about 800 grams.

 

Furnace before first charge.

 

Had two pieces come out. Here's the main one. Is about 770 grams.

 

Spark test of beginning material.

 

Spark test of furnace material. Same belt, same grinder speed, same pressure as the starting material picture. Any thoughts on carbon content? Also, as I was consolidating it after pulling out of the furnace, it seemed super solid. I was not able to move it much with a 4 pound hammer.

I may need to try this soon. Forgive my ignorance but what fuel is in the furnace....just hardwood?

On 1/10/2021 at 2:59 PM, Bill Schmalhofer said:

I have been wanting to try a hearth furnace for several months now, but a leak in the master bathroom and the resulting repair work has had me occupied for a long time. Today I finally said I need eda mental health day and to do something fun. So hearth furnace run one. Did the (what seems to be becoming the ) standard 7 brick furnace with the blower from my first coal forge. Charged it with 5 - 200 gram charges of A36 that I had sitting around. Time between charges was about 5-6 minutes. Total recovery was about 800 grams.

 

Furnace before first charge.

 

Had two pieces come out. Here's the main one. Is about 770 grams.

 

Spark test of beginning material.

 

Spark test of furnace material. Same belt, same grinder speed, same pressure as the starting material picture. Any thoughts on carbon content? Also, as I was consolidating it after pulling out of the furnace, it seemed super solid. I was not able to move it much with a 4 pound hammer.

I may need to try this soon. Forgive my ignorance but what fuel is in the furnace....just hardwood?

On 1/10/2021 at 2:59 PM, Bill Schmalhofer said:

I have been wanting to try a hearth furnace for several months now, but a leak in the master bathroom and the resulting repair work has had me occupied for a long time. Today I finally said I need eda mental health day and to do something fun. So hearth furnace run one. Did the (what seems to be becoming the ) standard 7 brick furnace with the blower from my first coal forge. Charged it with 5 - 200 gram charges of A36 that I had sitting around. Time between charges was about 5-6 minutes. Total recovery was about 800 grams.

 

Furnace before first charge.

 

Had two pieces come out. Here's the main one. Is about 770 grams.

 

Spark test of beginning material.

 

Spark test of furnace material. Same belt, same grinder speed, same pressure as the starting material picture. Any thoughts on carbon content? Also, as I was consolidating it after pulling out of the furnace, it seemed super solid. I was not able to move it much with a 4 pound hammer.

I may need to try this soon. Forgive my ignorance but what fuel is in the furnace....just hardwood?

On 1/10/2021 at 2:59 PM, Bill Schmalhofer said:

I have been wanting to try a hearth furnace for several months now, but a leak in the master bathroom and the resulting repair work has had me occupied for a long time. Today I finally said I need eda mental health day and to do something fun. So hearth furnace run one. Did the (what seems to be becoming the ) standard 7 brick furnace with the blower from my first coal forge. Charged it with 5 - 200 gram charges of A36 that I had sitting around. Time between charges was about 5-6 minutes. Total recovery was about 800 grams.

 

Furnace before first charge.

 

Had two pieces come out. Here's the main one. Is about 770 grams.

 

Spark test of beginning material.

 

Spark test of furnace material. Same belt, same grinder speed, same pressure as the starting material picture. Any thoughts on carbon content? Also, as I was consolidating it after pulling out of the furnace, it seemed super solid. I was not able to move it much with a 4 pound hammer.

I may need to try this soon. Forgive my ignorance but what fuel is in the furnace....just hardwood?

On 1/10/2021 at 2:59 PM, Bill Schmalhofer said:

I have been wanting to try a hearth furnace for several months now, but a leak in the master bathroom and the resulting repair work has had me occupied for a long time. Today I finally said I need eda mental health day and to do something fun. So hearth furnace run one. Did the (what seems to be becoming the ) standard 7 brick furnace with the blower from my first coal forge. Charged it with 5 - 200 gram charges of A36 that I had sitting around. Time between charges was about 5-6 minutes. Total recovery was about 800 grams.

 

Furnace before first charge.

 

Had two pieces come out. Here's the main one. Is about 770 grams.

 

Spark test of beginning material.

 

Spark test of furnace material. Same belt, same grinder speed, same pressure as the starting material picture. Any thoughts on carbon content? Also, as I was consolidating it after pulling out of the furnace, it seemed super solid. I was not able to move it much with a 4 pound hammer.

I may need to try this soon. Forgive my ignorance but what fuel is in the furnace....just hardwood?

[Bill Schmalhofer]

@Kreg Whitehead,I think you need to cut back on the caffeine!

 

Warning, this stuff can become addictive. Alan wasn't lying about sucking you in.

 

It's just hardwood lump charcoal. I've been buying 33 pound bags of Cowboy hardwood charcoal at Costco. If you run furnaces sequentially, you get more bang for the buck as you don't have the waste getting it started and a bed of coals made. It took only a little more than 2/3 a bag of charcoal for my last three runs.

 

I'm debating trying a run using anthracite coal sometime here (or at least mixing some in with a charcoal run). I've been told it is a vastly different beast than using charcoal, but I have 40-50 pounds of nut coal sitting in my garage gathering dust and that is not including the 30 or so pounds of rice coal I have right next to it. Just not a lot of information on the web on how to run a anthracite furnace like there is for charcoal runs.

[Bill Schmalhofer]

2 hours ago, Jerrod Miller said:

RFQ generally stands for "Request For Quote".  They may be quoting several tests to get really high accuracy across the board.  OES, Leco Carbon/Sulfur, gases, etc.  Getting just OES should certainly be much closer to $100.  Definitely is just over $100 at IMR, as I got that done there pretty recently.  

This is what testing method they were quoting me plus some incidentals for lab prep, etc. The incidentals actually ran more than the actual test.

 

8 different runs, one run for each element I had said I was interested in.

 

Chemical analysis for Low Alloy Steels, Stainless Steels, and Aluminum Alloys     ASTM E1097-12/CTP 3005/ DCP

 

[Jerrod Miller]

DCP-AES is going to be expensive and accurate.  OES will be cheaper.  

[Alan Longmire]

12 hours ago, Bill Schmalhofer said:

anthracite furnace

 

It took the most experienced smelters in the world over a hundred years to figure out how to use anthracite for smelting.  But it can be done, and I don't know how... 

[Bill Schmalhofer]

4 hours ago, Alan Longmire said:

 

It took the most experienced smelters in the world over a hundred years to figure out how to use anthracite for smelting.  But it can be done, and I don't know how... 

I have the coal. I have the bottle caps. I have the time. No harm in doing it to see how big a mess I can make...

 

Besides the wife keeps asking when I'm going to do something with the two big bags of coal that I've had for 6 years (first bought it for use in my coal forge - didn't work too well there).

[Alan Longmire]

You may need to add calcium in the form of either agricultural lime or crushed oyster shell.  Something has to act as slag, and anthracite fly ash isn't ideal.  Nor is bituminous coke, but it works.  

[Bill Schmalhofer]

36 minutes ago, Alan Longmire said:

You may need to add calcium in the form of either agricultural lime or crushed oyster shell.  Something has to act as slag, and anthracite fly ash isn't ideal.  Nor is bituminous coke, but it works.  

Do you think sand or charcoal briquet ash work?

[Alan Longmire]

Briquets are mostly coal and glue, but sand could do.  And good call, calcium promotes carbon uptake, and can end as cast iron when you want steel.

[Kreg Whitehead]

That last post of mine I kept hitting submit reply....it appeared it was never gonna work so I gave up. lol

I really wanna try this. Sounds like you do not put all of the steel in at once.

Do you just lay it on top of the coals...or do you try and stuff it down a bit.

What is it your bricks are setting on.....is it of any importance.

I picked up another propane tank a few months ago.

Do you think that would make a good furnace if I stood it on end?

I have left over wool and refractory cement from my forge build.....would that be beneficial?

Is there a reason I would not want to add a bunch of blade scraps from profiling?

Is there a book I can buy? 

[Alan Longmire]

31 minutes ago, Kreg Whitehead said:

Is there a book I can buy?

 

If only!  This forum is, barring personal instruction by someone who has done it, the best resource I know of.   There is a Facebook group for it too, with many of the same people, but I don't do FB so I don't know what's there.  Look up every thread on hearth melting, Evenstad hearth furnaces, Aristotle furnaces, finery furnaces, etc.  Mark Green, Emiliano Carrillo, Lee Sauder, Jesus Hernandez, these are the names to look for.

[Bill Schmalhofer]

4 hours ago, Kreg Whitehead said:

That last post of mine I kept hitting submit reply....it appeared it was never gonna work so I gave up. lol

I really wanna try this. Sounds like you do not put all of the steel in at once.

Do you just lay it on top of the coals...or do you try and stuff it down a bit.

What is it your bricks are setting on.....is it of any importance.

I picked up another propane tank a few months ago.

Do you think that would make a good furnace if I stood it on end?

I have left over wool and refractory cement from my forge build.....would that be beneficial?

Is there a reason I would not want to add a bunch of blade scraps from profiling?

Is there a book I can buy? 

Watch this video (first pinned topic in this sub-forum). It is what started me down the rabbit hole when I saw "how easy it was".

 

If you have nice compact charges (like wrought iron or 1018 / A36 biscuits) you can lay the material right on top and bury it in charcoal. I've been having "fun" with my charges as I am using all kinds of scrap. The charges are big and lumpy and /or full of air (it is REALLY hard to pack bottle caps together). I've been having to pack them down a little otherwise I can't load the charcoal charge on top.

 

I actually made a clay base from material I harvested from my yard. It has shallow indents the size of the bricks to help hold them together in a ring. Then I place that ring on a bed of broken scrap soft fire bricks to keep from scorching the grass in my yard. In the video you'll see that Emiliano just has them sitting on a hard brick platform. I don't think the base is that important. Just something fire proof. My guess is you could probably dig a shallow 2-3 inch deep hole, pack the soil down a bit and make your ring of bricks in that.

 

It's so easy to over think this process on a basic level. First time I did it I was thinking I was forgetting something but it worked (also what has gotten me hooked - I've had 5 runs and every single one has worked - just jinxed myself ). I'm not trying to imply that it is so easy anyone can do it. I'm goofing around right now and testing the waters. I'm going to guess the hard part (and where the people Alan mention shine) is getting good enough to make reproducible material and not just a crap shoot of material.

 

I'll say the hardest  part I've found right now is consolidating the pucks down to bar stock. Lots of flux and a freaking screaming hot forge make it less of a task.

 

Now I'm going to venture into the territory of the blind leading the blind (as if this novel hasn't been that already). I am by no means good at this but I will give you my opinion on your idea for a furnace. I don't think the tank lined with wool will be a good furnace. I base this opinion (and it is an opinion) on a two points. 1) The inside of the furnace is full of charcoal not a hot burning gas. The wool is going to get beat to heck really fast. When the wool is gone, your furnace body suddenly becomes part of the melt. 2) most of the time to get the puck out, it is easier if you remove a brick to get into the bottom of the charcoal bed. Can't do that if the walls are solid.

 

To your second to last point, the starting material you want to use is low carbon. My understanding of the main purpose of this process is to add carbon to iron. If you start with a high carbon blade material you stand the very real chance of making cast iron not steel. My first run I used scrap A36. A real crap steel, but it probably started around 0.2-0.3% carbon. The material I ended up with was probably pushing 1.5-2%. I wouldn't venture to guess where you would end up if you started at 0.6-0.9% carbon. My runs with bottle caps have netted me material that is sparking somewhere in the neighborhood around 0.8%.

 

Lastly, take everything I wrote with a (large) grain of salt. As I said, I have done this all of 5 times. I've had luck and no bad runs so far. Not much experience, but what I have I am more than happy to pass on.

 

Sorry for the novel. Talk about needing to lay off the caffeine!

 

[Kreg Whitehead]

A couple of last questions.

Are those just standard bricks....or some kind of fire brick/blocks?

The place I buy my refractory stuff from says the largest fire blocks they have are 9"x4.5"x3"

Also for a blower....would a leaf blower work? If not I am open for suggestions there.

[Geoff Keyes]

A leaf blower is probably 50 times more air than you need.  50-100 cfm (about the size of a bathroom fan) is what you need.  Remember, smiths used to blow air through the with a hand pumped bellows/

G

[Alan Longmire]

Emiliano uses standard half-slab firebrick.  Ordinary red brick will melt.  And yeah, a leaf blower is WAY more air than you want for that size of furnace.  You'd end up wearing the charcoal.   I use a little 100CFM squirrel cage blower choked by around 80%, or a shop vac on a rheostat (a variac, actually) turned down to 10%.  A router speed control from Harbor Freight will do it for a standard shop vac.  

[Bill Schmalhofer]

I've just been using standard hard fireplace brick 9 x 4.5 x 2 and I still slag them. Regular brick as Alan said will melt in a heart beat (or explode if they are a little wet on the inside).

 

The little blower I'm using I actually have to have full bore open during the actual process. I think is it rated 75-100 CFM.

[Bill Schmalhofer]

So what I've been able to gather about using anthracite coal in smelting of iron is that it started in the late 1830's. Probably the crucial step / discovery was made by Neilson in Scotland with the invention of the hot blast furnace. He may or may not have know the importance of his discovery, as I think he was actually working on this for a different process, but he is credited with it. Basically due to the difficulty in getting anthracite to ignite and burn the idea was to pre-heat the air being blown through the furnace to about 300 degrees F (although hotter is better) which allowed the anthracite to burn more efficiently (and more importantly, keep burning) . This also allowed the use of raw coal instead of coke. There have been more changes to the process to improve it, but this was the pivotal issue that made anthracite viable in smelting.

I have not been able to find out anything else that is critical for the use of anthracite for smelting other than this. The fact that I won't be using it to smelt ore to iron but using it to imbibe carbon into iron / scrap gives me an advantage (I hope ).

 My idea to accomplish a hearth furnace run using anthracite is to make a square hearth furnace instead of the "normal" semi-round. Then pipe the tuyere around the bricks and have it then enter the hearth body. To help with preheating the air, I am also thinking of loosely wrapping the bricks and piping in kaowool.

 

Start a fire using charcoal to get the pipe hot and then switch over to anthracite.

 

Okay, everybody can now tell me why my idea won't work. Ready...Go!

[Alan Longmire]

I think you'll need a few more loops of pipe to get a true hot blast.  In the big furnaces they run the exhaust through a big brick "stove" almost the size of the furnace itself, and run the incoming blast through said stove. 

I agree you're just trying for carbon uptake, and the carbon in anthracite is not as available as in coke or charcoal. The thing to remember is that the uptake comes from carbon monoxide,  not solid carbon.  Thus the need for really good combustion.

I'm not saying it won't work, but I think you may need more preheating. I like your ambition, sir! 

[Jerrod Miller]

My first thought was to have the pipe over the top of the opening of the furnace.  If your furnace is say a 12"x12" square, make your pipe sit just inside that as if you were starting to make a lid for the furnace.  The fire isn't as hot up there and you have a bunch of cool air flowing through the pipe, so you shouldn't risk damaging it too bad.  And you should still have plenty of room to add your charges.  If it still isn't hot enough you could lower it down into the furnace a little, or shim it up further away if it gets too hot.  I wouldn't think losing a little volume to the top of the furnace would be a big deal, but then again it all depends on how big your pipe is vs your furnace.  

[Bill Schmalhofer]

So, I finally received the analysis of the two consolidated bars of steel I made.

Several observations and questions:

 

The first and most depressing is that at some point during the folding, I “lost” almost all my carbon. This was pretty unexpected as during the folding I was running my forge at a fairly reducing atmosphere as well as having exogenous carbon present (I always run my forge with several large pieces of anthracitic coal present). Feedback on possible reasons always welcome. After getting the pucks to initial bars, they both sparked nicely. Then I didn’t check again until I had forged the swarf bar into a knife blank. I noticed that as I was grinding it the sparks were not very inspiring. I now know why.

 

The second observation is that the S and P are nicely low in the swarf starting material and OK in the bottlecap material. Will S&P at the levels from the bottle caps affect the steel adversely? I ask because I am assuming that these results are going to be typical for this starting material. If this level is going to be an issue, then I’m not going to waste fuel trying to process it, as bottle caps through a hearth furnace are a PITA.

 

Third observation is that it is a mixed bag as to what happens to the alloy ingredients off a grinder. Most of the swarf material is from my Damascus grinding. Up until recently all my Damascus was a combination of 15N20 and 80CrV2. Nickel and copper seem to make it through the best followed by chromium. Based on the “general guidelines” for both these steels, the low manganese is interesting; it doesn’t seem to make it through. I also have questions concerning the loss of chromium - why did it go down so much in the swarf material and was actually higher in the bottlecap material? Does chromium get “burned up” in the grinding process? Does it combine with carbon going up in the atmosphere during the melt? And for those wondering where that much copper came from in the swarf material – probably from the cans I packed the swarf in to be able to load it in the hearth furnace. This raises the question; will this much copper negatively affect the quality of steel? If so, I will need to figure a new way to load the swarf into the furnace.

 

The last (depressing) observation is that I seem to have figured out a way to make expensive “high nickel A36”. I have to work to increase the beginning carbon content of my pucks. The comment concerning the bi-polar nature of pucks by Daniel Cauble in Aiden CC last post are food for thought.

 

Now that I have the analysis and know some of what I have to change, it is time to start planning the next melt.

[Jerrod Miller]

4 hours ago, Bill Schmalhofer said:

Will S&P at the levels from the bottle caps affect the steel adversely?

I think you should be fine at those levels, though the S is getting to the worrisome level.  Still, it is not likely to be a problem.  Especially since you don't have much Mn to form MnS.  

 

4 hours ago, Bill Schmalhofer said:

I also have questions concerning the loss of chromium - why did it go down so much in the swarf material and was actually higher in the bottlecap material? Does chromium get “burned up” in the grinding process? Does it combine with carbon going up in the atmosphere during the melt?

Combines with the oxygen and goes into the slag.  Here is the Ellingham-Richardson Diagram for you.  It shows the preference for oxidation as a function of temperature.  Not the easiest chart to read, but the best version I have on hand.  The Ca being the lowest line means it is the first to go react with oxygen, copper being one of the last (and Ni is close to that).  One of the cooler things from my perspective is the red carbon line (2C + O2 -> 2CO).  We definitely have times where C all of a sudden starts liking O more than other things, and that is when things get pretty interesting since most of the other oxides forming are liquid or possibly even solid, the CO bubbles out as a gas.  It is known as a "carbon boil".  

 

4 hours ago, Bill Schmalhofer said:

This raises the question; will this much copper negatively affect the quality of steel?

Lower would be better, but I would think this is still very much workable.  

 

[Alan Longmire]

Well, that just sprained my brain...   One of these days when I can read that chart clearly I'll be in trouble. 

 

I was at a loss to answer your other questions, but the carbon one I suspect has to do with dwell time in the melting furnace.  Not enough exposure to CO for long enough, thus not a lot of carbon uptake on the bottle caps, and maybe too much O2 in the swarf, decarburizing the steel.  In both cases, the solution is to cut back on the air blast.  The ultra-reducing atmosphere in your forge doesn't hurt, but you're not spending enough time in there for it to do a lot of good, either.  

[Bill Schmalhofer]

2 hours ago, Jerrod Miller said:

I think you should be fine at those levels, though the S is getting to the worrisome level.  Still, it is not likely to be a problem.  Especially since you don't have much Mn to form MnS.  

 

Combines with the oxygen and goes into the slag.  Here is the Ellingham-Richardson Diagram for you.  It shows the preference for oxidation as a function of temperature.  Not the easiest chart to read, but the best version I have on hand.  The Ca being the lowest line means it is the first to go react with oxygen, copper being one of the last (and Ni is close to that).  One of the cooler things from my perspective is the red carbon line (2C + O2 -> 2CO).  We definitely have times where C all of a sudden starts liking O more than other things, and that is when things get pretty interesting since most of the other oxides forming are liquid or possibly even solid, the CO bubbles out as a gas.  It is known as a "carbon boil".  

 

 

Lower would be better, but I would think this is still very much workable.  

 

Very interesting chart Jerrod. If I am reading it correctly (and my pyrometer is correct – when I am consolidating the pucks down and folding, I’m running the forge flat out as possible and the temperature pegs the meter at 2400+F), this could explain some of the loss. So, the metal lump that I pulled out of my forge when I re-lined it probably had high carbon, high chromium, and high everything else. Maybe I shouldn’t run so hot next time. But it was really interesting to consolidate the puck down to a bar. Basically I put the puck in and almost watched it melt into a solid lump. 

 

On the red line; does that show at what temperature carbon boil happens?

 

1 hour ago, Alan Longmire said:

Well, that just sprained my brain...   One of these days when I can read that chart clearly I'll be in trouble. 

 

I was at a loss to answer your other questions, but the carbon one I suspect has to do with dwell time in the melting furnace.  Not enough exposure to CO for long enough, thus not a lot of carbon uptake on the bottle caps, and maybe too much O2 in the swarf, decarburizing the steel.  In both cases, the solution is to cut back on the air blast.  The ultra-reducing atmosphere in your forge doesn't hurt, but you're not spending enough time in there for it to do a lot of good, either.  

I agree Alan, serious brain strain on that chart. As another question that I am now pondering based on Jerrod's comment (Combines with the oxygen and goes into the slag), I am also wondering if it is possible to use too much borax as flux when consolidating? Does the borax lower the melting point of all oxides or just iron? 

[Alan Longmire]

Borax works on all metallic oxides, that's one of the old prospector's assay tricks.  Put a bead of molten borax in a little loop of platinum wire (it doesn't work on platinum, no oxides, you see), add a grain of mystery ore, and the color the bead turns along with the color the flame turns when put in a blowpipe flame tells you what elements are present.  Generally, when consolidating a puck of hearth/Aristotle/bloom steel you don't flux it, relying instead on the slag from the ash and furnace walls.  If it's too nasty, a little clean silica sand and/or wood ash works.  Rice straw ash is better, it's higher in silica.