Quenching an anvil in a river, with an excavator - GIF

[will52100]

Old anvils were generally wrought iron, some welded up from two or three pieces, with a 1/2" or so thick high carbon steel face forge welded on. That's where the "step" comes from on London pattern anvils and the face is fully hardened.

Others, like my Reffinghause anvil are hardened to a depth of about an inch. It's good to have a soft core, but that's more from the fact that it's nearly impossible to cool that large a chunk of steel fast enough than from design, it just works out that it's a good thing.