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K340 ISODUR is an electroslag-remelted tool steel from Böhler. It is worth distinguishing from K340 ECOSTAR, which uses a different production route and has small composition differences. This profile and its composition table focus on ISODUR, so check the exact version when a knife listing simply says K340.
K340 ISODUR and ECOSTAR Are Different Versions
Böhler specifies electroslag remelting, or ESR, for ISODUR. ECOSTAR is conventionally air-melted. Their published average silicon and chromium values also differ. The composition below applies to ISODUR; ECOSTAR has its own specification. ESR is not powder metallurgy.
What Does the Specification Tell You?
Böhler describes ISODUR’s toughness and wear properties in a tooling context. Those statements help explain its intended role, but they are not a set of knife performance ratings. For a finished blade, look for the maker’s heat-treatment information and consider the edge geometry. The processing label cannot guarantee a particular knife’s resistance to chipping or wear.
Sharpening and Protecting the Blade
Keep this non-stainless tool steel clean and dry after use, and protect it during storage. Use a food-safe oil if the knife contacts food. For sharpening, select an abrasive and grit that cut effectively, follow a consistent angle and remove the burr. A coated blade still needs care along its exposed edge.
Check Which K340 You Are Buying
Ask the maker which version is used if the listing is unclear. A clear ISODUR specification is more useful than a generic claim about premium steel, but the handle, grind and intended task remain central. Do not pay for an assumed process advantage without confirming the material and the finished knife’s details.
Composition
Our composition guide explains what alloy values can and cannot tell you.
Böhler K340 ISODUR: Böhler K340 ISODUR average analysis only; ECOSTAR differs; selected reported elements, not a finished-blade assay. Böhler: K340 ISODUR.
| Element | Böhler K340 ISODUR |
|---|---|
| Carbon (C) | 1.1% |
| Silicon (Si) | 0.9% |
| Manganese (Mn) | 0.4% |
| Chromium (Cr) | 8.3% |
| Molybdenum (Mo) | 2.1% |
| Vanadium (V) | 0.5% |
Compare Two Knife Steels
Sources and Update Notes
This steel is not included in the numerical ratings used by our comparison tool.
