Jacob Morgan - I just wanted to say thank you for sharing that info. Whilst I have no history in metalworking not any specific need to do so in the immediate future, it's posts like this, more than anything else that would make me want to become a blacksmith - seeing the 'inner workings' of stuff like this is really interesting to me, and knowing the scientific reasons behind specific actions e.g. how metal hardening works etc I think is much more valuable than simply being told "It's hard because it has been hardened, and that makes it hard".
So, thank you for sharing - it's much appreciated!