I’m just an amateur guy who messed with metal on occasion
And straight up not following the logic
I know heating and quenching makes it harder, which is good for knives and such, but also makes it more brittle I guess? And likely to crack?
The descriptions on this subject are literally “over explaining the scientific molecular composition of metal” or “so anyway make hot then make un hot, dat good”
But I was trying to bend some metal today, heated it up a few times and got it near its shape, then cooled it by quenching so no one would grab it and burn their hands on it while I stepped away, came back and heated again and it just broke lol
In: Other
Master’s degree in material science:
Not every metal is “heat treatable”.
Steel is funny because the carbon acts like a road bump to the iron matrix it resides in – a road bump in the sense that iron remains ductile until it encounters defects (caused by carbon).
If you increase carbon enough you get something very brittle (cast iron).
If you add just the right amount of carbon and heat treat it you can control how much iron-carbon solute comes out of solution (this is all solid state, but it helps to think of something like sugar and water in solution).
If you heat a steel and quickly quench it, you freeze a lot of iron-carbon solute – this is not stable. This is very brittle, but also very hard.
If you now heat treat the steel (raise to a certain temperature and leave it) the unstable iron-carbon solute tries to reach stability – BUT – you can just cool it down to “freeze” that state. The perfect combination of strength, toughness (ability to not crack), and hardness.
Heat treatment is nothing but slowly introducing equilibrium back to a steel but stopping it before it gets all the way there. If you leave steel quenched but not heat treated, it’s very unstable, which is why it’s like glass.
Latest Answers