N680 steel, by BOHLER,  contains about 0.20% nitrogen and over 17% chromium making it extremely corrosion resistant.  If your blade will be in frequent contact with salt water for example then this is the steel for you.  It’s also a fine grained steel that can take a very fine edge. Consider it a cheaper alternative to H1 steel with decent edge retention but it won’t hold an edge as long as say, 154CM.