Böhler M398 Microclean is an ultra-high-alloy powder metallurgy stainless steel that serves as the "extreme" evolution of the famous M390. While M390 is known for its balance, M398 is engineered specifically to push edge retention and wear resistance to the absolute maximum.
It is currently one of the most high-performance stainless steels available in the premium knife market.
Key Characteristics
Extreme Edge Retention: By significantly increasing the Carbon and Vanadium content over M390, Böhler created a steel that stays sharp for an incredibly long time. It outperforms almost every other stainless steel in pure cutting longevity.
High Hardness: It is designed to be heat-treated to 61–63+ HRC. This high hardness allows for a very stable edge that resists rolling during fine cutting.
Outstanding Corrosion Resistance: With 20% Chromium, it remains a true stainless steel. It offers the same elite rust resistance as M390, making it safe for use in wet or acidic environments.
Lower Toughness: The trade-off for its extreme wear resistance is brittleness. M398 is more prone to chipping than M390 or Elmax. It is a specialized steel for slicing and precision work; it should not be used for high-impact or heavy-duty prying.
Very Difficult to Sharpen: Because it is packed with such a high volume of hard vanadium carbides, it is much harder to sharpen than M390. Diamond abrasives are highly recommended to maintain an edge on this steel.
Chemical Composition
Comparing it to M390 shows a massive increase in the elements that drive hardness and wear:
Carbon (C): 2.70% (Up from 1.90% in M390)
Chromium (Cr): 20.00% (Remains high for rust resistance)
Vanadium (V): 7.20% (Nearly double the 4.00% in M390)
Molybdenum (Mo): 1.00%
Tungsten (W): 0.70%
Common Applications
High-End Slicing Knives: Ideal for custom folding knives and premium hunting knives where the user wants the longest-lasting edge possible.
Luxury EDC Folders: Used by brands like Shirogorov and other elite manufacturers for their top-of-the-line models.
Industrial Applications: Used in high-wear plastic processing and injection molding for abrasive materials.
M398 vs. M390
M398: Significantly better edge retention, but more brittle and harder to sharpen.
M390: Better all-around balance, tougher, and easier to maintain for the average user.
Would you like to explore Böhler K390, which offers similar extreme edge retention but in a non-stainless tool steel formula?