Not carbonation, I'm talking about how to put carbon into steel. One of the greatest challenges when making high carbon steel is getting carbon into it. Sure, it can start as high carbon, but when you work with it the carbon is quickly released.

For example: when you fold the steel used to make a katana the high carbon steel loses carbon with each fold which is not a good thing. Many steps are used to keep as much of the carbon in the steel as possible such as dousing the hot steel in ashes(carbon) and heating the steel in different ways such that the metal heats from the inside out instead of from the outside in, the latger releases tons of carbon and makes the katana useless.

So I'm looking for ways to introduce more carbon into steel. Back to the metal folding katana example, I was thinking maybe you could fold thin of carbon wafers inbetween the folds of steel. Maybe you could drill a ton of holes into the steel and steep it in a charcoal slurry.

How do you go about adding carbon to high carbon steel?