52100
This steel has a fine carbide structure made up almost exclusively of a small volume of relatively soft iron carbides enriched with chromium. As a result, this steel is very easy to sharpen on conventional ceramic or natural wet stones. If you are interested in more information on this steel I have covered it on my Instagram as part of my ongoing Steel Saturday series!
Originally developed as a bearing steel 52100 is now commonly used by many custom knife makers. 52100 maintains a good balance of hardness and toughness all the way up to 65RC. This combined in combination with its extremely fine microstructure make 52100 a great choice for users who enjoy sharpening and want to chase the finest edges