Posted: 5/12/2005 7:21:38 PM EDT
| Why does heating steel reduce it's brittle state? |
So it's more of a balancing act and integrating additives. Kind of like adding carbon to iron, correct? |
i found that out when i was cutting some tungsten with wire cutters......shit was tough as hell then it just fell apart completely. i had no idea it was so brittle 
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gee.....w/o knowing the specifics on what in particular you are askin about, i'll give it a shot in martensetic steel, (hardenable, like spring or tool steel), when you heat it above 1250f, the iron molecule changes from a body centered molecule to a face centered...this means that a particle of carbon is trapped inside the iron molecule, till you heat it above 1250f.....then, the molecule shifts, and the carbon goes up to the face of the molecule........if you quickly cool this, the carbon will be trapped on the face of the molecule, and will be very, very hard and brittle....the carbon won't let the iron molecules slide past each other...... but, this also traps a huge amount of stress into the steel.....so, reheating or tempering, is used to reduce the stress, and to increase the toughness for the intended application......tempering is done from approx 350-1150f..... tempering lets some of the carbon slip off the face of the molecule, and lets some of the molecules slide a bit... this is an extremely simplified version of what goes on in simple carbon steel alloys..... some steels act in the exact opposite way......you harden them by low temp soaking, and anneal or soften them by getting them very hot, and quenching in water......brass and copper do this also.... i know this is a bit vague, but w/o knowing specificly what your askin about, it's about as good as i can do later skintback |
I was watching a blade making show on the History Channel. Some of the things they said didn't make complete sense. You cleared up what I didn't understand. Thank you. |