In this video I will be covering the pros and cons of using charcoal or pig iron in your crucible steel, along with some tips on how to use them effectively.
Keep your eye out for info about the International Wootz Society, which is a group that I'm helping get off the ground that will be an excellent resource on all things wootz related.
I’ve recently made an ingot using about 50% mild steel and the rest I used 5-6% O1, 30-35% S7, a few small carbide endmills, and some railroad steel. The thing is very heavy, and does not want to forge, it started to crack apart on me..so..I’m going to be making a charcoal forge and getting a hydraulic press.
It sounds like your alloy level ended up too high, and possibly the carbon level also. I would suggest starting with fairly low alloy levels until you are comfortable with the process, and from there you can ramp up the alloy levels slowly if desired. A good way to start is by making something similar to a steel that you are already familiar with forging; that way there are fewer variables to deal with at the beginning. It is surprisingly easy to accidentally make a steel that is completely unforgeable, so starting in known territory is a good idea.
Great video! Thanks for putting out these videos. On another note I'm dying to see your rolling mill up close and in use if possible! I've been looking at alternative designs to the mcdonald rolling mill, yours looks very interesting!
I’ll try to get some more footage of it in use sometime soon. I’ve never used the MacDonald Mill, but it is definitely a simple, effective design. There are advantages and disadvantages to all the mill designs, so the real trick is figuring out exactly how you will use it. Once you know the intended uses you can decide which design makes the most sense.
I have been able to get about ten melts per crucible. Longevity of the crucible depends substantially on how clean your materials are going in. The fewer oxides the better.
@@peterburt7218 if I do have pure Graphite Crucibles how does that change the Chemistry of the Ingot? Or does it just shorten the lifespan of the Crucible?
@@samsmith2635 A pure graphite crucible shouldn't be used for steel melting because the molten steel will quickly dissolve the graphite. Carbon is soluble in Fe, so this would be like trying to heat water in a pot made of sugar. In Clay-graphite crucibles the Fe is contained by the clay portion of the crucible, while the graphite acts to stabilize the crucible against thermal shock. Pure graphite crucibles are used exclusively for nonferrous metals (other than platinum) because the graphite helps to deoxidize the metal. They can't be used for platinum because Pt can also absorb C and create carbides.
I have been interested in trying crucible steel for a long time and the information in your videos has giving me enough confidence to finally go for it. I do have a question for you about the sorel pig iron. Do you get it from Miller and Company or is there another source? If you do get it from Miller, what are they like to deal with, do they do small orders? It would be great to know before contacting them.
I always ended up contacting local foundries because the larger suppliers simply don't want to sell in small enough quantities. The last time I checked they were looking to sell at the 1000# size rather than perhaps 50#, which is what would be reasonable for most smiths. It's not expensive material, but shipping on 1000# isn't cheap. If you check around you can often find a foundry that uses Sorel or one of the other high-purity pig irons, and most foundries are perfectly happy to sell 50#. Good luck!
Hello and thank you for the excellent video and information! I need to ask for help. I will be trying my first wootz melt in the upcoming months. For my first attempt I'll be using charcoal as a carbon source and wrought iron(300 grams of it) plus 10 grams of a HSS hacksaw blade as a source of carbide forming elements. The only problem is, I've looked and looked all over the internet but could not find a formula a ratio or anything to calculate what amount of charcoal I would need if I want to get 1.6% carbon in my 310 gram charge? Also you mentioned that hardwoods have more minerals in them, does that mean they should be the choice for charcoal over softwoods? Thank you very much for your attention!
@@peterburt7218 Actually now when I think about it, I'd prefer to use common nails since you said mild steel is ok to use. What would be the calculation for mild steel? It's just that the wrought iron I have is in very large pieces and I have no power hammer nor press, and nails are very easy to cut into small pieces.
Softwood charcoal is preferred since a larger proportion of the weight is carbon rather than minerals. To calculate your ratio, multiply the charge weight x carbon %...in this case 310 x 0.016 to get a carbon requirement of roughly 5g. There will be some C in the nails, plus the charcoal won’t be 100% C, so there is obviously some amount of unknown in the calculation.
@@peterburt7218 I want to thank you profoundly for the priceless information and your time! I have one last thing to ask, you said the charcoal should be on the bottom of the crucible and mild steel on top, I was wondering since I will be using the smallest possible nails to maximize my chance of a successful melt, if I cut the nails into even smaller pieces and mingle them with my charcoal powder will that work out or not? Since you mentioned the charcoal may float away with the slag if improperly placed.
Carburization is definitely a factor of surface contact, so the more contact the better. If you are going to use just nails and charcoal then you might divide the nails into three portions and load as follows: one third of nails in the very bottom along with some crushed glass, one third of nails combined with crushed charcoal, then the last third of the nails on top to keep the charcoal from floating out as the slag melts. The slag layer goes over the nails, and I typically load a small amount of lump charcoal on top of that to burn off excess oxygen in the early stages. If all goes well the middle layer of nails will melt first as it absorbs carbon from the charcoal, and that liquid flows down into the bottom layer and begins carburizing and dissolving those nails. At the same time the upper layer should collapse downwards into the melt. One major advantage of using pig iron to carburize is that it is naturally a top-down melt and “bridging” is unlikely.
I add a very small amount of vanadium carbide powder, which will readily dissolve in the molten iron. Keep in mind that historical wootz had alloy contents so low that they were essentially ignored by metallurgists until quite recently. Values of 0.04% and below are quite common in historical blades.
would it help to reduce some of the charcoal issues by pre-heating it? Have a scale set up with a proper heat-resistant container and zeroed out. Run the charcoal up to glowing for whatever period of time might be useful to eliminate the water content and burn off more of the undesirable elements, dump the charcoal on a metal screen so you can thump the screen to remove charcoal dust, if necessary, dump the hot charcoal on the scale, get your desired weight, then dump it still hot into the crucible and quickly add your metal, is what I had running through my idiot brain.
Heating will definitely remove a substantial portion of the water weight, and I believe a temp of even 400f would be sufficient. The other difficulty with charcoal is the mineral content...essentially the material that would be left over as ash if the charcoal was burned completely. This varies from tree species to tree species, and even to some degree within an individual tree. As a rule of thumb, the denser the wood the higher the mineral content. If I made my own charcoal and always used the exact same wood and firing temp, I could narrow the variables substantially...or I could just use graphite and know that I have essentially 100% carbon.
Hi Peter, Thank you for your informative vidéo. Is it possible to use rusty steel to make wootz or do I have to grind it first? Thank you for your answer.
It’s a good idea to clean your material as much as possible before putting it in the crucible. I don’t go crazy with this, but I definitely wire brush away any loose oxides. There are a few good reasons for this. 1) oxides throw off the carbon calculation, since reducing them to iron removes C from the melt as CO gas. 2) iron oxide melts at a lower temp than iron and will run to the bottom of the crucible. Iron oxides are very corrosive to most refractories, so the more oxides the shorter the life of the crucible. 3) some of the CO gas created during reduction of the iron oxides will dissolve in the molten iron, and this is forced out of solution during solidification. This leads to more porous ingots, sometimes so much so that the ingot must be scrapped.
I definitely would not add anything plated to the melt. There is no way of knowing how much you are adding of different elements, and not much certainty about exactly what is in the plating. Many plating processes require several layers of different metals. Chromium (Cr) is not inherently good or bad for crucible steel; it just depends on what you are aiming for. Cr is a reasonably good carbide-former, and also acts to deoxidize the molten steel. Nickel (Ni), on the other hand, should really be kept out of any hypereutectoid steels, though it is fine in eutectoid and hypoeutectoid steels.
Gray cast iron can give you the C content, but unfortunately also brings a huge amount of silicon along with higher levels of sulfur and phosphorus than you want in steel. If you are looking at cast iron for your steel, I would suggest malleable or ductile cast iron, which have tighter chemistry than gray cast iron. McMaster-Carr, MSC, and Online Metals are good places to look for these in bar form.
Thank you again for all the details!! Very helpful!
Keep your eye out for info about the International Wootz Society, which is a group that I'm helping get off the ground that will be an excellent resource on all things wootz related.
@@peterburt7218 Thank you Peter I will look for it.
Extremely interesting, you got me hooked, I need to know more!
It’s a deep, deep rabbit hole!…but totally worth it!
I’ve recently made an ingot using about 50% mild steel and the rest I used 5-6% O1, 30-35% S7, a few small carbide endmills, and some railroad steel. The thing is very heavy, and does not want to forge, it started to crack apart on me..so..I’m going to be making a charcoal forge and getting a hydraulic press.
It sounds like your alloy level ended up too high, and possibly the carbon level also. I would suggest starting with fairly low alloy levels until you are comfortable with the process, and from there you can ramp up the alloy levels slowly if desired. A good way to start is by making something similar to a steel that you are already familiar with forging; that way there are fewer variables to deal with at the beginning. It is surprisingly easy to accidentally make a steel that is completely unforgeable, so starting in known territory is a good idea.
Great video! Thanks for putting out these videos. On another note I'm dying to see your rolling mill up close and in use if possible! I've been looking at alternative designs to the mcdonald rolling mill, yours looks very interesting!
I’ll try to get some more footage of it in use sometime soon. I’ve never used the MacDonald Mill, but it is definitely a simple, effective design. There are advantages and disadvantages to all the mill designs, so the real trick is figuring out exactly how you will use it. Once you know the intended uses you can decide which design makes the most sense.
Great intro video!
Thanks! I’ve got more on the way!
Really great informative video Peter! I can't wait to try out a melt. How much use are you typically able to get out of those crucibles?
I have been able to get about ten melts per crucible. Longevity of the crucible depends substantially on how clean your materials are going in. The fewer oxides the better.
@@peterburt7218 if I do have pure Graphite Crucibles how does that change the Chemistry of the Ingot? Or does it just shorten the lifespan of the Crucible?
@@samsmith2635 A pure graphite crucible shouldn't be used for steel melting because the molten steel will quickly dissolve the graphite. Carbon is soluble in Fe, so this would be like trying to heat water in a pot made of sugar. In Clay-graphite crucibles the Fe is contained by the clay portion of the crucible, while the graphite acts to stabilize the crucible against thermal shock. Pure graphite crucibles are used exclusively for nonferrous metals (other than platinum) because the graphite helps to deoxidize the metal. They can't be used for platinum because Pt can also absorb C and create carbides.
I have been interested in trying crucible steel for a long time and the information in your videos has giving me enough confidence to finally go for it. I do have a question for you about the sorel pig iron. Do you get it from Miller and Company or is there another source? If you do get it from Miller, what are they like to deal with, do they do small orders? It would be great to know before contacting them.
I always ended up contacting local foundries because the larger suppliers simply don't want to sell in small enough quantities. The last time I checked they were looking to sell at the 1000# size rather than perhaps 50#, which is what would be reasonable for most smiths. It's not expensive material, but shipping on 1000# isn't cheap. If you check around you can often find a foundry that uses Sorel or one of the other high-purity pig irons, and most foundries are perfectly happy to sell 50#. Good luck!
@@peterburt7218 Thank you very much, very helpful.
Hello and thank you for the excellent video and information!
I need to ask for help.
I will be trying my first wootz melt in the upcoming months.
For my first attempt I'll be using charcoal as a carbon source and wrought iron(300 grams of it) plus 10 grams of a HSS hacksaw blade as a source of carbide forming elements.
The only problem is, I've looked and looked all over the internet but could not find a formula a ratio or anything to calculate what amount of charcoal I would need if I want to get 1.6% carbon in my 310 gram charge?
Also you mentioned that hardwoods have more minerals in them, does that mean they should be the choice for charcoal over softwoods?
Thank you very much for your attention!
No problem. I’m always happy to answer specific questions.
@@peterburt7218 Actually now when I think about it, I'd prefer to use common nails since you said mild steel is ok to use.
What would be the calculation for mild steel?
It's just that the wrought iron I have is in very large pieces and I have no power hammer nor press, and nails are very easy to cut into small pieces.
Softwood charcoal is preferred since a larger proportion of the weight is carbon rather than minerals. To calculate your ratio, multiply the charge weight x carbon %...in this case 310 x 0.016 to get a carbon requirement of roughly 5g. There will be some C in the nails, plus the charcoal won’t be 100% C, so there is obviously some amount of unknown in the calculation.
@@peterburt7218 I want to thank you profoundly for the priceless information and your time!
I have one last thing to ask, you said the charcoal should be on the bottom of the crucible and mild steel on top, I was wondering since I will be using the smallest possible nails to maximize my chance of a successful melt, if I cut the nails into even smaller pieces and mingle them with my charcoal powder will that work out or not?
Since you mentioned the charcoal may float away with the slag if improperly placed.
Carburization is definitely a factor of surface contact, so the more contact the better. If you are going to use just nails and charcoal then you might divide the nails into three portions and load as follows: one third of nails in the very bottom along with some crushed glass, one third of nails combined with crushed charcoal, then the last third of the nails on top to keep the charcoal from floating out as the slag melts. The slag layer goes over the nails, and I typically load a small amount of lump charcoal on top of that to burn off excess oxygen in the early stages. If all goes well the middle layer of nails will melt first as it absorbs carbon from the charcoal, and that liquid flows down into the bottom layer and begins carburizing and dissolving those nails. At the same time the upper layer should collapse downwards into the melt. One major advantage of using pig iron to carburize is that it is naturally a top-down melt and “bridging” is unlikely.
Do you add any Ferro vanadium to encourage carbide seeding? Or any other elements?
I add a very small amount of vanadium carbide powder, which will readily dissolve in the molten iron. Keep in mind that historical wootz had alloy contents so low that they were essentially ignored by metallurgists until quite recently. Values of 0.04% and below are quite common in historical blades.
@@peterburt7218 Many thanks
would it help to reduce some of the charcoal issues by pre-heating it?
Have a scale set up with a proper heat-resistant container and zeroed out. Run the charcoal up to glowing for whatever period of time might be useful to eliminate the water content and burn off more of the undesirable elements, dump the charcoal on a metal screen so you can thump the screen to remove charcoal dust, if necessary, dump the hot charcoal on the scale, get your desired weight, then dump it still hot into the crucible and quickly add your metal, is what I had running through my idiot brain.
Heating will definitely remove a substantial portion of the water weight, and I believe a temp of even 400f would be sufficient. The other difficulty with charcoal is the mineral content...essentially the material that would be left over as ash if the charcoal was burned completely. This varies from tree species to tree species, and even to some degree within an individual tree. As a rule of thumb, the denser the wood the higher the mineral content. If I made my own charcoal and always used the exact same wood and firing temp, I could narrow the variables substantially...or I could just use graphite and know that I have essentially 100% carbon.
Hi Peter, Thank you for your informative vidéo. Is it possible to use rusty steel to make wootz or do I have to grind it first? Thank you for your answer.
It’s a good idea to clean your material as much as possible before putting it in the crucible. I don’t go crazy with this, but I definitely wire brush away any loose oxides. There are a few good reasons for this. 1) oxides throw off the carbon calculation, since reducing them to iron removes C from the melt as CO gas. 2) iron oxide melts at a lower temp than iron and will run to the bottom of the crucible. Iron oxides are very corrosive to most refractories, so the more oxides the shorter the life of the crucible. 3) some of the CO gas created during reduction of the iron oxides will dissolve in the molten iron, and this is forced out of solution during solidification. This leads to more porous ingots, sometimes so much so that the ingot must be scrapped.
@@peterburt7218 thank you, i will take your advice
@@peterburt7218 Just another question, is there any point in adding chromed metal or stainless steel to the crucible?
I definitely would not add anything plated to the melt. There is no way of knowing how much you are adding of different elements, and not much certainty about exactly what is in the plating. Many plating processes require several layers of different metals. Chromium (Cr) is not inherently good or bad for crucible steel; it just depends on what you are aiming for. Cr is a reasonably good carbide-former, and also acts to deoxidize the molten steel. Nickel (Ni), on the other hand, should really be kept out of any hypereutectoid steels, though it is fine in eutectoid and hypoeutectoid steels.
@@peterburt7218 Ok Thnak you.
Hi peter. Hope you dont mind me asking. Is it possible to use normal gray cast iron for carbon content?
Gray cast iron can give you the C content, but unfortunately also brings a huge amount of silicon along with higher levels of sulfur and phosphorus than you want in steel. If you are looking at cast iron for your steel, I would suggest malleable or ductile cast iron, which have tighter chemistry than gray cast iron. McMaster-Carr, MSC, and Online Metals are good places to look for these in bar form.
Ok that's great thanks very much.
Why not use powdered charcoal if it is a surface contact mechanism…?
Powdered charcoal would float more easily in the glass slag so there would be a better chance of it floating out. That has been my thinking, anyway.
Thank you! Your process really got me thinking!@@peterburt7218
Thats why im using pure graphite ;)
What are you using as your graphite material? I know some folks use motor “brushes”.
Im using normal graphite powder :)
Volume too low .
I'll see what I can do on future videos.