Primitive Technology: Decarburization of iron and forging experiments

Decarburization of iron and forging experiments

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About This Video:
I took a brittle, high carbon/iron alloy (cast iron) made from local ore and used a decarburization method to reduce it's carbon content making it malleable and forged it flat by hammering.

Rather than producing a single bloom of soft iron in my furnaces, as was done in most of history, I tend to produce cast iron prills from the ore. Cast iron is iron that has a very high carbon content. Its good properties are that it's very hard and has a low melting point. The drawback is that it's relatively brittle compared to regular iron. So I set about trying to find a method for reducing its carbon content.

In this video I smelted local ore (iron bacteria) and obtained cast iron prills. I then tried melting it in a small crucible to obtain a solid ingot to begin the experiment. This gave a poor result though with an incomplete melt.

Next I tried rusting the prills first with the intent of creating iron oxide (rust ) in the iron so that the next melt would combine the materials in an exothermic reaction that would burn the carbon out. In the past, rusty iron was added to cast iron to decarburize it (wet puddling/pig boiling). But this also gave poor results.

Finally, I did away with the mold and simply melted the iron prills by dropping them into the forge in front of the hot air blast of the forge. The reasoning was that the high oxygen would burn out the carbon from the metal. This caused them to melt together to form an ingot. After a few attempts I took one of the ingots and hammered it while still white to yellow hot and hammered it with a stone. The ingot was able to be flattened as it had become malleable. This was the result I wanted.

This method of decarburization (melting cast iron in a open hearth to make it malleable) was used throughout history at different times. In ancient China it was known as "stir fried steel/ 炒钢" and in the west known as the "Osmond process". I also read that in India, cast iron ingots from the crucible were brought to a temperature just below melting point before becoming forgeable.
In future experiments I hope to use this technique to decarburize iron ingots to make into forged metal tools as opposed to the cast knife I made in a previous video.

Chapters:
00:00 Overview of my standard smelting process
00:50 Crucible ingot (failure)
02:21 Decarburization via rusting (failure)
04:22 Decarburization without crucible (inconclusive)
05:45 Decarburization without crucible/forging (success)
07:01 Decarburized and forged iron result

About Primitive Technology:
Primitive technology is a hobby where you build things in the wild completely from scratch using no modern tools or materials. These are the strict rules: If you want a fire, use a fire stick - An axe, pick up a stone and shape it - A hut, build one from trees, mud, rocks etc. The challenge is seeing how far you can go without utilizing modern technology. I do not live in the wild, but enjoy building shelter, tools, and more, only utilizing natural materials. To find specific videos, visit my playlist tab for building videos focused on pyrotechnology, shelter, weapons, food & agriculture, tools & machines, and weaving & fiber.

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[primitivetechnology]

I think I figured out how to turn the brittle cast iron I've been producing into malleable iron that can be forged flat. When ever I smelt local ores it always produces cast iron prills rather than softer blooms of low carbon iron as one would expect from the bloomery process. I believe this because the prills are very hard, but when struck hard enough they shatter rather than flatten.

Cast iron is iron that has a high carbon content (when arranged by carbon content: Cast iron>Steel>iron). Cast iron has a lower melting point and is harder compared to regular iron. But it is more brittle so it's nearly impossible to forge. So I figured out how to decarburize it after some experiments.

First I tried making an ingot to work on but it didn't cast properly. Then I tried rusting the iron to oxidize the metal before melting so it would decarburize the cast iron during the melt (similar to the "wet puddling" process in metallurgy). But this gave an incomplete melt also.

The method that finally worked was simply melting the cast iron in front of the air blast till the carbon burnt out in the oxygen rich zone of the forge. This caused the cast iron prills to melt together in a single blob that I then was able to hammer flat while yellow hot.

This method is similar to the "stir fried steel/ 炒钢" process in ancient China or the "Osmond process" in Europe. It's done where ever cast iron needs to be converted to a lower carbon to be forged. I've seen videos about carburizing iron on youtube but none about decarburizing cast iron.

[k_meleon]

Don't you find it crazy how hard it is to make good quality iron? Just thinking about the people who had to come up with this technology before the advances of chemistry is mind blowing

[aboriani]

Years of pure quality content, 10 millions subscribers, not a single word spoken... A legend

[somanayr]

Hi, hobbyist blacksmith of about 7 years here. I know it goes against your ethos, but please consider wearing safety glasses while forging. Little flecks of iron can embed in your eyes without you knowing, destroying your eyes when you get an MRI

Other than that, this is so cool to see! It’s amazing how much progress you’ve made and it’s fascinating to see what’s possible

[MichaelS]

This man absolutely captivates the internet every time he drops a video.

[kyle]

When he first proved the theory of getting iron from the bacteria in the river it opened up the possibility that he would be progressing out of the stone age. Seeing MALLEABLE iron is a HUGE step towards that. Absolutely incredible.

[Yohrog]

This is why these experiments are so valuable as a historical resource. It's hard for us to imagine nowadays why it took tens of thousands of years to figure out how to make iron tools, given that we have mindblowing new developments every decade or so. Your videos really put things into perspective and helps people to understand how incredibly hard and complicated these processes where to even come up with.
You have modern science at your disposal as a reference. I could not imagine coming up with something like this if I didn't even know that iron was a thing, let alone that forging it is possible.

[KaikipBT]

"This technique is an important step towards forged iron tools"

I can't describe just how much this one little phrase excites me. You are simply the best. Watching you strike at the ingot had me worried for your safety though. You are a treasure and no one wants to see you hurt.

[radicaledward]

I really like that fact that you showed some of your failed attempts, it can be easy for us as viewers to just assume you figure everything out the first time and don't make mistakes but mistakes are all part of the process of learning and improving.

[NXaiUL]

Wow, he really took all the suggestions from his last video comments and implemented them.

Learning together with others might arguably be the most important primitive skill.

[SteelBerserkChannel]

I still remember when people joked that one day we would see you get to the iron age, and here you are. Amazing video as always, keep up the excellent work! Also if anybody hasn't got his book yet it's highly recommended!

[christianm]

This is honestly the only channel that I trust when it comes to primitive builds, all the other ones are most likely faked or staged. Kudos to this man for making it authentic.

[Nighthawkinlight]

This is great. Always excited to see your progress.

[zerofaith]

I love that you're teaching how painstaking it actually is to produce iron. Actually helpful and educational, you're truly great at what you do.

[song-of_king]

당신이 구독자 수 10만이었을 당시부터 즐겨봤던 한국의 열렬한 팬입니다. 당신의 유튜브가 이렇게 성장했음에 감사와 축하를 보내고 진실된 영상을 올리시는 것에도 존경과 감사를 표현합니다.


I am a big fan of Korea that you have enjoyed since you had 100, 000 subscribers. I also express my respect and appreciation for your YouTube growth and posting sincere videos.

[willsal]

I appreciated seeing your earlier attempts. The difficulty you encountered replicating this technology highlights what an achievement it was to develop it in the first place.

[GusCraft]

I blacksmith as a hobby, and I love what you are doing. It’s so cool to see how to do these things without the tools that we rely on today.

[TheEret]

Watching your progress from basically the stone age to the iron age has been so exciting! I can't wait for more!
Also a reminder to watch with captions on so you can get explanations for what he's doing! :D

[Psychopathicows]

Welp, you’ve officially advanced to the Iron Age. I am genuinely impressed. Not to mention how all of your subscribers have been watching the cradle and growth of civilization and technology from the comfort of our couches and toilets. You are truly one of the best the internet has.

[morranhaelkor]

This video not only proves that forging iron in primitive conditions is hard, time and resource consuming, but also how many other "primitive" channels are faking it. Thank you, for your great work and true content