Quote:
Originally Posted by Joe Chandler
. but plain water would allow the creation of a vapor jacket around the blade, slowing down the quench and rendering it ineffective for a steel like 1095 that needs a near immediate quench.
|
It's worthwhile to discuss the vapor jacket problem. It might cause a large piece of steel, say bowie knife sized, to have just enough of a delay that the heat treatment could be uneven (non uniform). But with the conversion of martensite from austenite running at the speed of sound (Verhoeven), when compared with a half to one second, as Russell points out "when it stops sizzling", the vapor jacket phase is very slow. The martensite's already done despite the bubbles. And unlikely to be much of an influence in a razor sized section of steel because there is significantly less mass to cool down across a much thinner section.
Even oils will have vapor jackets from the oil burning and flashing into smoke and they are considered slower quenches than water. Nobody seems to worry about the problem in an oil bath, but it keeps coming up with water because if the timing is right, there could be an influence.