I believe 3Guardsmen hit the nail
To me they are in order from least to greatest:
s stainless steel, and surgical stainless = not good for anything
410 stainless steel
= great handle and liner material which seems to be a common application for this grade of steel
420 stainless steel
= makes a great liner, but that's about it, never want to see just "420" on a blade
420J2 stainless steel
= great liner, but never want to see this on a blade steel, I believe CRKT uses this on some models.....those models go dull quickly.
420HC stainless steel
= when done properly (Buck Knives for example) it is a blade steel beyond it's metallurgical components, this can typically rank with some 440C or AUS8/AUS10 (see below for 440C and AUS8 and AUS10)
440A stainless steel and/or AUS6
= OK blade steel, great when done properly (such as Kershaw before they switched to sandvik). Mostly given poor heat treatment and not held very highly in the knife community (except when kershaw made it right).
440B and/or AUS8
= These two are very similar in their edge retention and sharpness, AUS8 is more widely used, but 440B and AUS8 make a great "medium" blade steel. Medium such as it's not the greatest at anything except being a little of everything....savvy?
440C and/or AUS10
= The king daddy-o before its crown was taken away by 154CM and ATS-34 (and all the other modern steels). Still widely used and revered as a great blade steel for edge holding, stainless, and hair whittling sharp
I hope this "crash course" in 400 helps, it's questions like this that lead me here to bladeforums in the first place. I wanted to know about blade steels and read up everything I could find.....3 years later and I am still reading up on stuff here :thumbup: