Bohler-Uddeholm S390 Knife Steel
Composition Analysis Graph, Equivalents And Overview

S390(Bohler-Uddeholm) - Bohler-Uddeholm PM steel. High speed, red hot hardness tool steel. Good toughness and wear resistance. Roughly equivalent of AISI T15 high speed tool steel. I'll soon move this alloy into its own group, since S390 Microclean isn't all that close to neither AISI T15 steel nor AISI M3:1Co, to warrant being in the same group. Meanwhile, Kase Knives Switzerland(kase-knives.com) just posted a video(09/23/19) with S390 Microclean testing results, where the thin bladed knife, with 0.02" behind the edge thickness edge managed to cut through the steel nail and brass tube, with no edge damage. The test knife was a very impressive 68HRC. Overall, from what we can see based on published data and Kase Knives tests, S390 Microclean steel can be an extremely high performer, and I suppose based on the heat treatment protocol used it can do very well with both, high performance cutters and, the larger, more heavy duty use knives. Also, worth noting, carbide size is in 3µm-5µm range, which is quite fine compared to many other high alloy steels.

Manufacturing Technology - PM

Country - Sweden(SE)

Known Aliases:
Bohler-Uddeholm - S390 Microclean

^* - Listed as an equivalent or replacement for alloys in this group.