What is AR-RPM9 steel?
AR-RPM9 stainless steel is a proprietary stainless steel that Artisan Cutlery has produced. It is formulated using powder metallurgy and is classified under their budget-priced Steels. AR-RPM9 steel’s 9 designation is meant to indicate the elements in the alloy composition.
According to the company, powder AR-RPM9 stainless will increase the performance of budget-friendly knives because it is comparable in performance to high-end steel.
One unique aspect of Ar-rpm9 compositions is the fact that artisans list RE elements to indicate the presence Rare earth elements. Artisan Cutlery does not specify which rare earth elements it uses, but lists RE at 0.05%.
AR-RPM9 Steel Composition (AR-RPM9 steel chart)
- Carbon 0.9%: Enhances edge retention, hardness, and tensile strengths. It increases steel resistance to wear, corrosion, and abrasion.
- Chromium Cro 18.00%: Chrome Increases the hardness, tensile and corrosion resistance of a blade.
- Molybdenum Mo 1.0%: Increases machinability, corrosion resistance.
- Vanadium V 0.1%: This is vanadium carbide that forms hard vanadium in combination with other elements to improve wear resistance.
- Manganese 0.45%: Increases steel’s strength and hardness. The steel’s hardenability can be improved by heating it.
- Nickel Ni 0.65%: Increases strength and toughness. It can increase hardenability, but not as much than other alloying elements found in steel. It can increase corrosion resistance by significant amounts
- Silicon Si 0.80% – Increases strength, heat resistance.
- Rare Earth Re0.05%
What is RE in ARRPM9 Steel?
Artisan Cutlery doesn’t specify which RE (rare earth) elements it uses to make AR-RPM9 stainless steel, though the most common RE elements used in steel production include Cerium (Ce), Lanthanum (La), and Lanthanum [Ce]. It would be reasonable to assume that Artisan Cutlery might use these elements in AR-RPM9 stainless.
Artisan Cutlery representative clarified RE in a recent interview with Knife Newsroom. He stated that it was essentially trace elements from the smelting process such as sulfur, phosphorus and so on. The sum of all trace elements is less than 0.05 percent.”
Phosphorus and sulfur are impurities that are most commonly found in steel production. They are not considered rare earth elements. The Artisan Cutlery representative’s statement raises questions about whether RE is a marketing strategy or just a marketing tactic.
AR-RPM9 steel properties
AR-RPM9 Steel Hardness
According to the Rockwell hardness scale, AR-RPM9 steel is between 58-60 HRC. This high hardness is expected to be found on high-end knives made by reputable brands such as Cold Steel and Spyderco.
High carbon content and high levels of cobalt and vanadium in the steel’s composition are responsible for its high hardness. AR-RPM9 steel is enhanced by hard vanadium carbides that improve its wear resistance and hardness.
ARRPM9 Steel Edge retention
Hardness directly influences the steel’s edge retention. It is not surprising that knives made of this steel have a high hardness of 60 HRC.
This steel’s ability to stay sharp even after repeated use is also due to the hard vanadium carbides.
ARRPM9 Steel Toughness
The steel’s toughness is defined as its ability to absorb impact without breaking down. It decreases with steel’s hardness.
AR-RPM9 steel is not expected to be tough. Although it is not the strongest steel, there are stronger steels available.
Artisan Cutlery recognized this and added elements to increase the steel’s toughness, such as nickel and manganese. These additions make AR-RPM9’s toughness decent.
ARRPM9 Steel Corrosion Resistance
AR-RPM9, which has 18% of chromium in it, is stainless steel. A steel that is deemed stainless steel must contain at least 12% of chromium. This steel has the same corrosion resistance capabilities as premium steel, with 18%.
The AR-RPM9 Steel will provide a great option if you’re on a tight budget but still want a knife that can withstand high corrosive environments.
Remember that steel of all types can rust when exposed to corrosive environments. For a long-lasting, rust-free service, wash and dry your ARRPM9 knives.
ARRPM9 Steel Wear resistance
Wear resistance refers to the steel’s ability to resist wear and abrasion. It is directly affected by its hardness. AR-RPM9 steel is very wear resistant due to its hardness. These knives are able to withstand tough applications without cracking or chipping.
AR-RPM9 knives are highly resistant to wear, but you shouldn’t use them for anything beyond their capabilities. Using them for extremely tough applications such as batoning is like setting them up for failure.
Easy Sharpening AR-RPM9 Steel
AR-RPM9 steel is hard steel. This means it is difficult to sharpen. The knives will not dull quickly, which is a good thing. However, it will take more effort to get the sharp edge back. If you’re a novice at knife sharpening, the process of sharpening will be more difficult.
Good news: You can still use normal aluminum oxide abrasives to sharpen Ar-rpm9 stainless Steel knives.
AR-RPM9 Steel Equivalent
The AR-RMP9 steel is essentially equivalent to Chinese HTML18MoV steel or German 1.4112 stainless Steel. Both are high-carbon and chromium steels with a hardness between 58-60 HRC. AR-RMP9 steel is comparable to existing steels in terms of performance. Only the AR-RPM9 steel has “Rare Earth”, which is identical to their compositions.
AR-RPM9 vs VG10 Steel
AR-RPM9 and VG10 steel have different performance. AR-RPM9 stainless is slightly more resistant to corrosion than Japanese VG10 stainless steel. It contains 18% chromium in its alloy composition.
VG10 steel performs better than AR-RPM9 when it comes to wear resistance and edge retention. VG10 alloy composition has a higher proportion of vanadium carbides, which is excellent for wear resistance and edge retention.
Both AR-RPM9 and VG10 knives steel have equal toughness. Both blade steels can withstand extreme applications without cracking or chipping. Their toughness is lower than other stainless steels, such as L steel or UUS 8 steel.
Because AR-RPM9 blades are less wear resistant, it will be easier to sharpen AR-RPM9 knives than VG10 knives.
AR-RPM9 steel vs D2 steel
AR-RPM9 and D2 steel are different in that AR-RPM9 is stainless steel, while D2 is a non-stainless steel tool steel. AR-RPM9 Stainless Steel blades are more resistant to corrosion and rust than D2 steel blades.
D2 steel has a Rockwell toughness of around 63 HRC while AR-RPM9 steel can reach up to 60 HRC. D2 steel blade steel has a higher hardness than AR-RPM9 steel, which makes it more resistant to wear and edge retention.
D2 knife steel is well-known for its wear resistance. However, it falls short in toughness. Due to its manufacturing process and alloy composition, powder AR-RPM9 knifesteel is more tough than D2 steel. An AR-RPM9 knife will experience less cracking and chipping than a D2 knife.
Sharpening AR-RPM9 knifesteel will be easier than D2 knifesteel. D2 steel is extremely resistant to wear and has hard carbides that are hard to sharpen.
Is AR-RPM9 good knife steel?
We can conclude that powder ARRPM9 steel is a good budget knife material based on the above properties. It is hardened to a high degree, has good edge retention, moderate wear resistance and excellent corrosion resistance.
It is not as sharply edge-resistant as powder steels from other crucible industries, such as S30V stainless.
This CJRB folding knife comes in a range of affordable colors. This folding knife also has G10 steel scales and a ceramic ball bearing liner lock, for quick deployment and closing.