We independently evaluate all recommended products and services. Any products or services put forward appear in no particular order. If you click on links we provide, we may receive compensation.
AR-RPM9 is Artisan Cutlery’s stainless knife steel, used in its Artisan and CJRB knives. It offers an option for everyday cutting without the rust care of a non-stainless blade. Its spray-form production is worth understanding, especially when a listing describes it as powder metallurgy.
What Is AR-RPM9?
Artisan describes spray-form production. Dr. Larrin Thomas examined the steel’s microstructure and concluded it was not conventional powder metallurgy; his article also describes his correspondence with Artisan. Some Artisan marketing copy still uses powder-metallurgy wording, so the terminology is not consistent across the brand’s pages.
What Does That Mean When Choosing a Knife?
Thomas describes AR-RPM9 as essentially a spray-formed version of 9Cr18MoV. He expects the process to improve toughness somewhat, with abrasive edge retention around 440C or a little lower. These are estimates from his analysis, not measured ratings for this collection.
For everyday slicing, the useful question is whether the knife’s grind, edge and handle suit your work. The manufacturing label alone does not establish an advantage over another knife.
Maintenance in Everyday Use
Keep the edge clean, dry the blade after wet use and choose a sharpening grit suited to the condition of the edge. A light touch-up requires less work than removing damage. Do not assume that a stainless designation removes the need for care or that the manufacturing label alone predicts sharpening effort.
What to Look for in an AR-RPM9 Knife
Look for a knife whose blade shape, edge geometry and handle suit your cutting. Treat claims about powder metallurgy cautiously and ask for support if they are central to the price or sales pitch. The brand’s formula is useful identification information, but it does not make every similarly composed steel equivalent or replace evidence about a finished knife.
Composition
Our composition guide explains what alloy values can and cannot tell you.
AR-RPM9: Artisan brand-reported composition; not a finished-blade assay. Artisan Cutlery: AR-RPM9 composition.
| Element | AR-RPM9 |
|---|---|
| Carbon (C) | 0.9% |
| Chromium (Cr) | 18% |
| Molybdenum (Mo) | 1% |
| Manganese (Mn) | 0.45% |
| Vanadium (V) | 0.1% |
| Cobalt (Co) | 0.3% |
| Silicon (Si) | 0.2–0.8% |
| Nickel (Ni) | <0.4% |
Compare Two Knife Steels
Sources and Update Notes
This steel is not included in the numerical ratings used by our comparison tool.
