I'm not a metallurgist, just an electrical engineer who works in instrumentation and control systems around the petrochem industry. I probably should have studied to be a metallurgical engineer in college, hindsight.
Inconel is a very high-temperature tolerant, very corrosion resistant alloy. We use it for thermocouple sheaths for high temperature applications that require some corrosion resistance (hazardous waste incinerators, hydrocarbon flares, high temp hydrocarbon furnaces).
Inconel comes in a number of different formulations...they go by numbered names like 600, 601, 625, 718, X750, 800, 825.
The various Inconel flavors tend to be mostly nickel (70%+), with some chrome (10-20%) and some iron (5-10%). So it is not a steel per se, but a nickel alloy.
It will not make a decent knife blade. For a knife blade, you must generally find a martensitic stainless steel, i.e. one that will readily harden to Rc55 or higher, preferably something that isn't too brittle at Rc59-61. These are usually always Cromium-Molybdenum steels in or around the 420 or 440 series, or their derivatives.
Stellite/Talonite are exceptions to the hardness and "blade means steel means iron" rule. We use stellite on things like throttling control valves and pump impellers where erosion resistance is a must. Very abrasion resistant stuff even though Rockwell C scale hardness is in the mid to upper 40's.
High vanadium CPM440V can perform well at Rc56-57 so is somewhat of an exception.
Inconel may take an edge, but it won't hold it. It isn't hard. Won't get that way either through heat treating. It will retain torsional and bending strength at high temperatures, so not all is lost! You have a potential crowbar for when global warming really kicks in! ;-)
[This message has been edited by rdangerer (edited 02-09-2001).]