420F

420F is a hardenable 12% chrome steel with higher strength, hardness, and wear resistance than 410. The free-machining variation of standard 420, it is easy to machine, grind, and polish and has certain nongalling or nonseizing properties in service. Used mainly for machined parts requiring high hardness and good corrosion resistance, it is not recommended for vessels containing gases or liquids under high pressure or for plastic mold cavities where a high mirror finish is essential.