What is INFI Steel?

Busse INFI Steel Knife

What is INFI Steel?

INFI steel is a proprietary non-stainless steel exclusively manufactured by Busse Combat Knife Co. INFI steel is known for its exceptional toughness due to its fine-grained microstructure and is well suited for heavy-duty knives.

There have been two versions of INFI steel. The older version contained nitrogen elements for hardening because it contained low amounts of carbon. The current INFI steel does not contain nitrogen and cobalt. It depends on carbon and vanadium for hardening.

It is not stainless steel because it only has 8% chromium in its composition, which is not enough to make it stainless steel. INFI steel is used to make high-quality knives that can be used for tough applications like wood chopping, fire preparation, and food preparation.

INFI Steel Composition

  • Carbon C 0.64%: Increases edge retention, hardness, and tensile strength. It also improves steel resistance to wear, abrasion, and corrosion.
  • Chromium Cr 8.12%: Increases hardness, tensile strength, and toughness of the blade by forming chromium carbide.
  • Molybdenum Mo 0.85%: It improves machinability and hardening property.
  • Vanadium V 0.33%: Increase wear resistance and toughness, it also improves corrosion resistance.
  • Silicon Si 0.63% Improves strength of steel

Properties of INFI steel

INFI Steel Hardness

INFI steel attains a Rockwell hardness range of 57-60 HRC, depending on the heat treatment used. This hardness is not enough to sustain an edge on very course cardboards or ropes, but most steels do not perform well with such except for premium steels like Maxamet. INFI steel is designed to offer a hardness and toughness balance; therefore, it falls in the category of soft steel.

INFI Steel Edge retention

The edge retention of steel is a major point of consideration when buying steel. It defines how long steel blades can hold a sharp edge with frequent use and is directly related to hardness. INFI is not very hard steel, but it offers decent edge retention. The presence of vanadium elements that form hard vanadium carbides positively impacts the edge retention of INFI steel.

INFI shines on edge retention when it comes to impact toughness edge retention. It maintains a sharp edge even under high impact whereas most other steels would roll their edges or chip during high impact. 

You can better the edge retention of the INFI blades depending on the type of Blade grind and angle you put on your knife. 15 degrees to 17 degrees angle will provide a very sharp blade however it won’t be as durable as 22 degrees sharpened edge which is most suitable for outdoor knives. 

INFI Steel Wear resistance

The wear resistance of steel determines its durability, which is directly influenced by the hardness of steel. Hard steels offer high wear resistance and vice versa. Despite being soft steel, INFI steel provides great wear resistance, which is attributed to its unique alloy composition. INFI knives do not deform or lose shape when used for tough applications and will serve you for a long time.

INFI Steel Toughness

The toughness of steel is inversely proportional to hardness. This means that toughness increases with reduced hardness, which is true with INFI steel. With its low hardness, it excels in toughness. The steel does not chip, break or crack when exposed to tough applications.

To prove how tough INFI is Busse Combat puts one of its blades through a flexibility test where they bent the blade to 35 degrees and it recovered perfectly straight after the bend. This test showed incredible toughness and lateral strength you can achieve with INFI blades.

INFI blades are ideal for tough applications and are most suitable for bushcraft knives. When used to cut tough wood, INFI blades remain intact or get a small ding which you can get rid of during sharpening.

INFI Steel Corrosion resistance

INFI steel is not stainless steel because it does not contain enough chromium elements to make it stainless steel. However, the molybdenum elements in its composition improve its corrosion resistance. INFI blade steel corrosion resistance is slightly better than D2 Steel and ATS 34 steel.

Therefore, the knives can be used in highly corrosive environments and hold up for a good while without rusting or corroding. Like many other knife steel, proper care and maintenance against rusting are crucial.

This involves washing and drying the INFI blades immediately after use. Additionally, remove the knives from their sheath and apply a coat of oil on the blades for long-term storage.


Due to its balanced chemical composition and softness, INFI steel is easy to sharpen. You can get a sharp edge with simple sharpening tools within the shortest time possible. The excellent balance of ease of sharpening and edge retention of INFI steel makes it easy to maintain.

Busse Combat recommends Stropping the edge of the blade on a ceramic stick rather than grinding the steel on normal sharpening tools. The recommendation is based on the fact that INFI does not easily chip on the edge during use hence no need to grind to even the edge out.

INFI Steel Comparison

INFI steel vs 3V

INFI is tougher, offers better corrosion resistance, and is easier to sharpen than CPM 3V. It is better than 3V because it provides a great balance of hardness, toughness, and corrosion resistance.

CPM 3V is better than INFI steel in edge retention and may cut twice as much as INFI blades. However, INFI is able to maintain an edge even on high-impact applications without chipping or rolling. INFI  blade steel also offers slightly better corrosion resistance thus less maintenance is required.

INFI vs. Maxamet

Maxamet steel is very hard steel and therefore offers better edge retention and wear resistance than INFI. Maxamet edge retention is better than most knife steel only competing with the likes of Rex 121 Steel and Z-Max steel

On the other hand, INFI offers higher toughness and is easier to sharpen than Maxamet because it is a softer steel. INFI steel also offers slightly better corrosion resistance than Maxamet steel hence less likely to stain under corrosive environments.

Is INFI good knife steel?

INFI steel stands out as excellent knife steel as it offers exceptional toughness, good edge retention, and average corrosion resistance.INFI blade steel is also easy to maintain due to how easy it is to sharpen.

INFI knives come at a premium price, but it is worth the price considering the combination of its features, especially the edge-holding toughness.

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