A few years back Skip Williams was playing with the concept of “hearth refining” after noticing that a “clinker” found at the bottom of Lee Sauder’s forge during the process of re-heating bloom iron turned out to be a nice chunk of steel. He remembered reading about a description of the process of carburization of iron into steel from a paper written by Aristotle. Skip built a small furnace in his backyard for the purpose of being able to run multiple experiments quickly and with a minimum use of charcoal. That little furnace of Skip’s was put through the paces during a gathering of smelt-heads and smelt-hands at Lee Sauder’s SmeltFest ’09 and from there the concept was shared with the folks at Don’s bladesmithing forum in a post that I made entitled “A different way of making steel.” The rest, like they say, is history.
Here is a link to Skip’s description of the process.
Here is a link to a very comprehensive PDF that Lee has written on the subject.
This is a link to the original post on Don’s forum.
This is a link to my first attempt at making a blade from the steel produced by this method.
I should not forget to mention the value of the papers written by Ole Evenstad in 1782 and what that means in terms of further experimentation into the process of carburization in the forge hearth. A process carried out by smiths for over two thousand years and described directly or indirectly in the archeo-metallurgy research of cultures from East and West. And while in my own experience, the process of carburizing bloomery iron or low carbon steel into high carbon steel seems straight forward, taking the process in the other direction, from cast iron to steel has remained hit&miss and quite elusive to my attempts.
Stay tuned to this channel as I am not likely to give up on finding a solution with more consistent and reproducible results on the process of decarburization.