Hi everyone, I thought I'd use this post to introduce myself. I started smithing about three months ago. As I began messing around, I quickly found out what the term "burnt iron" was.
I work in the lab of a grey/ductile iron casting foundry in NEPA, under a fantastic and very experienced metallurgist. He has been helping me along throughout my progress, but with my question concerning burnt iron, he couldn't help (he had never heard the term).
So last weekend, while working in the forge, I purposely burnt the end of a rod, bringing it to its liquidius temp (honestly didn't think I could do that). I cut two pieces: one burnt and one untouched. The microstructure of the untouched steel shows constant grain boundaries, while the other was disturbed, air-quenched, changing it to martensite and/or bainite, depending on the layer. Basically, as far as I could understand, the force of oxygen combined with the carbon, which cause a loss therein, disrupting the grain boundaries.
I am far from a metallurgist, just a lab rat. If you guys have any further input, I'd really appreciate..correct me if I'm wrong.
Burnt
Untouched
I also ran a 1/2 gram sample in out Leco carbon and sulfur analyzer, and found that the untouched steel contained .326% carbon, and .125% carbon burnt.
This forum is great, and I hope to learn/contribute more.