"Eggs-zackly". Most/many people do not realize that "stainless steel" is not one alloy but many different(way more than thirty), under three general classifications, Ferritic, Austinetic, and Martinsitic. Martinsitic stainless steels can be hardened in common quenching means (oil and water). However Austenetic steels usually employ a sub-zero quench (liquid Nitrogen?), to achieve full hardness. You gots to know what it is and what to do with it.The stainless steels that are used in firearms can be heat treated, but you have to know WHAT the steel is, and what procedures are needed to bring it to what level of hardness, and for what purpose.
I some special applications it is...Kershaw knives used to advertise: "... high carbon AUS series stainless steel, using an advanced sub-zero quench ...", in some of their knife blades. Which always peaked my curiosity inasmuch as AUS (Austinetic) stainless-es, to the best of my knowledge are low carbon.Austenitic stainless is rarely quenched.