A small green parrot
- Jan 13, 2015
- Reaction score
In hot steel, chromium atoms are phat and slow in comparison to the quick little carbon atoms which zip around and latch onto irregularities in the steel. Chromium atoms move slowly enough that they themselves can be viewed as irregularities from a carbon atom's point of view. Carbon will latch onto these irregularities to create new carbides (nucleation), which results in finer and more numerous carbides over a situation where the carbon was left to it's own devices - where it would quickly wonder further around till it found a large group to join.The confusing aspect about such assumptions, and I'm not saying they're wrong but probably misinformation/misinterpretation on my behalf, is that the finer grained and low alloyed a steel, the more it should resist chipping (not much carbides creating "stress points" at the edge) but tradeoff would be lesser wear resistance and edge retention. That was my understanding. And as such White #2 is among the simplest carbons out there, shouldn't it be quite resistant to chipping? I'd expect it at least to be on par with 52100, for the matter of that discussion, if pure science as I understood it applies?
Carbon moves so quickly through these low alloy steels (e.g. White#2) that they're known as fast water quenching steels. Too slow a quench would allow the carbon to quickly move out of solution and find a carbide to call home before the steel cooled down enough to slow the atom down and hold it in place. That kind of required quench speed is a good indication of how quickly things are changing inside the steel, and may help in understanding why carbides can get larger in a lower alloyed steel. And of course, as you said yourself, larger carbides will lower the toughness of the overall product.