Tool steel is the usual preferred choice for large knives though many have used SS. The thinking behind it is usually based on the bladesmiths bend test where the spine of a "carbon" steel blade is tempered more than the edge thus allowing for a more "flexible" (softer) blade along the spine for heavy use (chopping) whilst retaining a hard (tough) edge for cutting. There is always a trade off between the two. A blade that's too hard is prone to chipping but retains an edge well and is good for small knives whilst a large blade that is softer won't have as good edge retention. The terms I've used here aren't the correct scientific terms but convey the idea behind it. Usually someone comes along with the correct terminology ensuring no one understands them unless they have a masters in metallurgy
I said tool steel in the beginning to differentiate between carbon steel and Stainless but both steels contain carbon and as such are carbon steels. The alloys differ to achieve there respective properties, but all knives are mostly carbon steel.
To answer the original question. Yes and no. You need bigger equipment for larger blades and most steels require temp controlled HT equipment but there are some tool steels that don't and can be heat treated with reasonable accuracy using traditional methods (coal or gas). Like the 10 series, 5160, O1 etc. More modern alloys require more controlled environments.
The process of heat treating and tempering differs to almost every steel type used and the tempering process can vary according to blade type and required use. That's why every steel type has a data sheet with recommended, tried and tested methods.
For example, I am currently busy with a very large bug out knife in N690. It was hardened in my oven at the required temp that I would use for any size knife in N690 but the soak time would vary to how thick the steel is. This one is 6mm. I then had my friend temper it in his tempering oven at 180 deg C for 1 hour and it came out at 58 RC which for me is 100% fine for a large knife that is primarily for chopping. For a smaller knife I would aim for 59/60 RC, maybe even 61 RC in N690 and that would give me a knife with good edge retention yet still able to field sharpen with basic tools. Some steels can get up to 64/65RC with amazing edge retention and the process would be different with them, some even requiring sub zero quenching, but how the hell do you sharpen that in the field? To me that's one very important aspect of a knife. Knife making can become a very complicated science with some of the steels used today. But the tried and tested steels that have been used over the last century are still being used coz they do what they are supposed to and for the average knife maker it doesn't require a bank loan from the Devil to work with them.
5160 has been used on large (and smaller knives) for a long time because it works and because bladesmiths have sold the "it will bend not snap" story with there HT process. Don't put aside some SS's though. Randal has used 440B for years with good results and many use N690 on large blades. I still say if you can snap a 6mm N690 knife then you should of been using a chain saw.
