eli5: if steel is made by mixing carbon and iron at high temp, what happens when you add carbon to other metals like brass, copper or gold? does it make “brass steel”?

Question

eli5: if steel is made by mixing carbon and iron at high temp, what happens when you add carbon to other metals like brass, copper or gold? does it make “brass steel”?

In: 276

Answer 1

There’s a pretty simple answer to this one: Steel is an expression of Carbon (C) and Iron (Fe) and their relative ‘sizes’. C happens to be just the right size and chemistry to fit into spaces in a crystal lattice of Fe. When done right this greatly strengthens that crystal structure, which is achieved through cycles of heating and quenching to specific temperatures. Specifically when you heat up Fe enough and dope it with C, then really rapidly cool it, the C prevents the Fe crystal structure from relaxing back into its original shape. The result gives us a really hard, durable material called Steel.

There are other alloys of metals, brass being one you mentioned, but they aren’t Carbon alloys because only Fe really fits the bill for that specific size, chemistry, and crystal lattice.

(Note, it isn’t strictly true that *only* Carbon fits the bill, you can get Nitrogen and Boron steels and so on, but this is a SUPER complex topic that can’t be fully covered here)