We’ve been using CPM MagnaCut since its first availability in 2021 and have transitioned all our knives to it. MagnaCut is the best
balance of the key blade properties of toughness, edge retention and corrosion resistance ever created in a stainless cutlery steel.
We and other knife manufacturers, in the early days of MagnaCut, discovered that the new steel had a greater than expected learning curve. For example, we had spent years working with CPM S35VN which has around 14% chromium. In the annealed (“soft” and workable) state cutlery steel is sold in, S35 was already quite rust resistant. So, during pre-heat-treatment machining and processing we had minimal issues with corrosion. However, MagnaCut’s relatively low chromium content (about 10.7%) is lower than most other stainless grades which makes it surprisingly susceptible to rusting if left wet for hours after machining deburr (eg in tumbling media). By design, MagnaCut only achieves its high corrosion resistance after heat treat. Just one example from the learning curve.
With MagnaCut heat treatment, there are a lot of options: balance the 3 properties mentioned above or choose to optimize one or two. MagnaCut heat treatment has been controversial since its release. There was a lot of focus on maximizing edge retention (hardness or HRC), with knife enthusiasts clambering for “getting the most” out of MagnaCut’s potential by heat treating for maximum HRC (64-65). To do so required sacrificing toughness and some corrosion resistance which to us seemed to be breaking the fabulous balance of great properties the steel can offer. In addition, we were specifically after the toughness that came with no large chromium carbides. This was especially the case for our outdoor models because we had had quite a few experiences with S35VN edge chipping: we wanted a tougher replacement. So when we first used MagnaCut, we stuck with the then recommended austenitizing temperature and toughness-optimal temper to aim for 60-62 HRC. Quite conservative but still an excellently preforming blade. We have had basically zero edge chipping since switching to MagnaCut, while maintaining our standard 15 degree per side sharpening.
With time and experience, we decided to adjust our HRC target range while only sacrificing a tiny bit of toughness. We currently shoot for 62.5 HRC, with a published range of 61-63 HRC. Interestingly, the developer of MagnaCut, Larrin Thomas, made a post in January 2026 comparing the original Crucible MagnaCut to the “cleaner” (fewer oxide inclusions) Erasteel version and found that the Erasteel version can be austenitized at about 100F higher while still retaining the same toughness as the Crucible version. This also translates to higher HRCs at the same toughness. He plans to monitor production batches from Erasteel over time to see that these results hold up. We continue to follow his results and expect to incorporate his conclusions into our evolving MagnaCut heat treat recipe.
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