M390

M390 is one of the best-known premium knife steels of our time – and a steel with Austrian roots. Here are the key facts:

Origin: M390 ("Microclean") comes from Austrian specialty steelmaker Böhler in Kapfenberg, Styria, and is produced by powder metallurgy. It was developed in the late 1980s (patent filed in 1989), originally not for knives at all but for the plastics industry, where tools need to be both wear-resistant and stainless. It was one of the earliest stainless powder steels, yet only found its way into knives years later: first with individual European custom makers (e.g. Dietmar Kressler, 1999), then its breakthrough around 2010 with major production brands like Benchmade and Kershaw. Today it is one of the most widely used steels in high-end pocketknives.

Composition: M390 consists of the following main elements:
Carbon (C): approx. 1.90%
Chromium (Cr): approx. 20.0%
Vanadium (V): approx. 4.0%
Molybdenum (Mo): approx. 1.0%
Silicon (Si): approx. 0.70%
Tungsten (W): approx. 0.60%
Manganese (Mn): approx. 0.30%

Of interest to collectors: M390 was so successful that it was copied almost identically twice – as CPM-20CV (originally from Latrobe, now Crucible) and as CTS-204P (Carpenter). If you see either name on a blade, you're essentially holding an "M390 twin." There is also M390MK, a variant tuned exclusively for Microtech, and M398, an even more wear-resistant successor.

Hardness: usually 60–62 HRC in knives.

Toughness: rather low – clearly below tougher powder steels like S35VN or MagnaCut. Perfectly adequate for pocketknives and normal cutting tasks, but not the first choice for very thin edges under heavy stress or rough outdoor work (prying, chopping).

Edge Retention: M390's greatest strength – in CATRA testing clearly ahead of S30V and far ahead of classic steels like 440C or VG-10.

Corrosion Resistance: very good – better than S30V, S35VN, or the Japanese powder steel SG2. Only specialists like LC200N or MagnaCut rank higher.

Practical Takeaway: For years, M390 has been something of the benchmark among premium pocketknife steels: it stays sharp for a very long time, resists rust very well, and takes a beautiful mirror polish. Surprisingly, despite its edge retention, it is somewhat easier to resharpen than some steels with comparable edge-holding, because a large share of its carbides are softer chromium carbides. The trade-off is toughness – if you want a rugged work knife for heavy use, MagnaCut or S35VN are the better pick. For everyday carry, however, M390 is close to ideal.