Bohler-Uddeholm M398 Knife Steel
Composition Analysis Graph, Equivalents And Overview

M398(Bohler-Uddeholm) - Bohler-Uddeholm introduced M398 steel in 2019. At least that's when it appeared on various knife related forums. M398 is intended as an evolution and improvement over a well known Bohler-Uddeholm M390 steel. As far as pure wear resistance is concerned, it definitely is an improvement. M398 has a lot more Carbon, 0.70% more of it, and 3.2% more Vanadium -making it whooping 7.20%. Obviously, this isn't a steel which is easy to work with, M390 steel wasn't an easy one to begin with. From what I've gathered so far, forging is theoretically possible but very difficult, only at low temperatures, with low strength impacts. Other than that, it's a very high carbide volume steel, 30% to be precise, for comparison, it's predecessor - Bohler-Uddeholm M390 steel had only(!) 20% carbide volume. In the end, both, working hardness and wear resistance have been increased, sacrificing toughness in process. I've seen a few M398 knives already, one of them in 66-67HRC range, which is pretty impressive. I'd be interested to get my hands on one of those. I'd guess neither sharpening, nor finishing the blade will be an easy task. Based on the characteristics, M398 is better suited for smaller, high performance cutters, and I'd also assume that this isn't the steel suited for high polished, acute edges, just like many other high carbide volume, highly alloyed steels.

Manufacturing Technology - PM

Country - Sweden(SE)