Beyond the Sharpness: Is HAP40 Steel Good for Knives?

Sharpness dreams made real? You’ve heard whispers of HAP40 steel, the mythical metal promising laser-like cuts and legendary edge retention. But before you empty your wallet, let’s slice through the hype. Is HAP40 steel good for knives, or just another steel fairy tale?

We’ll peel back the layers, from edge-holding prowess to sharpening woes, unveiling whether HAP40 deserves a place on your cutting board or just in your cutlery fantasies. Let’s get sharpening!

What is HAP40 steel?

HAP40 steel is a high-speed tool steel known for its exceptional hardness and edge retention properties, making it a favorable choice for knife blades. Composed of high levels of tungsten, molybdenum, vanadium, and other alloying elements, HAP40 offers a fine-grain structure that enhances its cutting performance. This steel is often used in high-end kitchen knives and outdoor utility knives where sharpness and durability are crucial.

While HAP40 provides excellent edge retention, it is not immune to corrosion, so proper care is necessary to prevent rusting. Regular maintenance, such as drying the blade after use and applying a protective coating, can help preserve its longevity. Additionally, some users appreciate the challenge of sharpening HAP40 due to its hardness, while others may find it requires specialized tools.

HAP40 steel chemical composition

Element	Portion	Effect
Chromium	4.7%	Improves wear resistance, heat resistance and scale resistance. It increases tensile strength because it acts as a carbide former. Use of rust-proof or stainless steel, as it increases corrosion resistance from a mass proportion of 12.2%. Reduction in weldability.
Cobalt	8.5%	Improve hot hardness, corrosion and wear resistance. Increase in tensile strength and yield strength, but at the expense of toughness. carbide former.
Carbon	1.27%	Increasing hardness and tensile strength. In larger quantities, increase in brittleness and a reduction in forgeability and weldability.
Molybdenum	5.4%	Improves hardenability, tensile strength and weldability. Reduction in forgeability and ductility.
Vanadium	3.3%	Increasing hardness, increasing wear resistance and improving tempering resistance.
Wolfram	6.5%	Increase in heat strength, tempering resistance and wear resistance at high temperatures up to red heat.

As you can see from the well HAP40 is a mixture of chromium, molybdenum, tungsten, cobalt, vanadium and carbon, elements that provide great hardness and toughness.

What is the hardness (HRC) of HAP40 steel?

The hardness of HAP40 steel ranges from 64 to 68 Rockwell hardness (HRC), which is significantly higher than the hardness of most common kitchen knife steels, such as stainless steel (55-58 HRC) or even high-carbon steel (58-62 HRC). Remember, the Rockwell C hardness of knives and blades made with HAP40 is usually around 65 HRC.

Here’s a comparison of HAP40 steel hardness to other common materials:

Fingernail: 2.5 HRC
Penny: 3-4 HRC
Stainless steel knife: 55-58 HRC
High-carbon steel knife: 58-62 HRC
Rockwell C scale diamond indenter: 70 HRC
Tungsten carbide: 70-90 HRC

Is HAP40 rust-free or a stainless steel?

HAP40 steel is not rust-free. To be considered rust-free it would require a chromium content of at least 10.5 – 13% chromium which must be dissolved in the austenite or ferrite (see here), depending on the definition. Meaning, it must be maintained.

However, it is stainless steel because its sulfur and phosphorus content (so-called iron companion) does not exceed 0.025% (see here). From this point of view, it is a FAST WORKING STAINLESS STEEL.

HAP40 steel properties

According to its chemical composition and hardness, it offers the following properties:

• Edge retention: with a maximum HRC of 68, the steel offers extremely good cut resistance, perhaps the best cut resistance you will find in a high-carbon steel.
• Corrosion Resistance: With a chromium content of only 4.7%, it lacks quite a bit of chromium to be considered stainless, so for sure it is not particularly corrosion resistant.
• Wear resistance: High wear resistance due to the mixture of chromium and high levels of molybdenum, tungsten, cobalt, vanadium and carbon.
• Sharpness: The harder a steel, the more difficult it is to sharpen. HAP40 is a very hard steel, so it is not easy to sharpen.
• Machinability: HAP40 is not an ideal steel for machining.
• Toughness: HAP40 is a tough steel, but at the expense of corrosion resistance, because unfortunately, it is not possible to combine more than two of the desired properties in the triumvirate of hardness, toughness and wear resistance in one material.

Related: Does M2 steel justify knife blades?

Is HAP40 a good knife steel?

YES, HAP40 is a great steel for knives: its edge retention is excellent, as is its hardness and toughness. So, for those who intend to take their knives really hard, it would be an excellent choice. It is considered one of the best steel in the Japanese cutlery industry.

However, if you need to use it predominantly in damp, wet, or even corrosive environments, you should rather look at H1 or LC200N.

On the other hand, its reduced corrosion resistance does not mean that it rusts easily – but it just needs more care than other extremely corrosion-resistant steels.

HAP40 steel equivalents

HAP40 steel belongs to the family of high-speed tool steels, and while there may not be exact equivalents, there are similar steels with comparable characteristics. Some steels that share similarities with HAP40 include:

• M4 Steel: M4 is known for its high carbon and vanadium content, offering excellent hardness and wear resistance, similar to HAP40.
• S30V Steel: S30V is a premium stainless steel with a combination of high wear resistance and corrosion resistance, making it a good alternative to HAP40 in certain applications.
• VG-10 Steel: VG-10 is a stainless steel often used in high-quality kitchen knives, offering a good balance of hardness, sharpness, and corrosion resistance.
• CPM S110V: Another high-alloy stainless steel, CPM S110V, is known for its exceptional wear resistance and edge retention.
• CPM 3V Steel: CPM 3V is a tough tool steel with good edge retention, making it suitable for heavy-duty applications, though it may not match HAP40’s hardness.

HAP40 steel equivalents based on edge retention:

• Akers Supra4: Matches HAP40 in edge retention while offering higher toughness and slightly easier sharpening.
• CPM Rex 45: Boasts even better edge retention than HAP40, but comes with increased brittleness and higher cost.
• Bohler-Uddeholm S590 Microclean: Similar edge retention to HAP40 with improved corrosion resistance and slightly easier sharpening.

Equivalents based on affordability:

• Daido DEX40: Offers very good edge retention and wear resistance at a more budget-friendly price compared to HAP40.
• Crucible CPM 154CM: A classic high-performance steel with solid edge retention and toughness, making it a versatile and cost-effective alternative.
• Vanadis 30: Provides excellent edge retention and toughness, although availability can be limited and prices on par with or slightly higher than HAP40.

Equivalents based on specific needs:

• Z130CW55V (Elmax): If corrosion resistance is crucial, Elmax excels with exceptional edge retention and rust resistance.
• M390: For a good balance of edge retention, toughness, and ease of sharpening, M390 presents a worthy contender.
• K390: Prioritize chipping resistance alongside good edge retention? K390 boasts enhanced toughness while performing well in sharpness.

Final Words: Is HAP40 steel good for knives?

All in all, HAP40 is a great knife steel. It makes a high-end steel knife that offers everything you could want in a knife steel.

In my opinion, despite its low corrosion resistance, it is one of the best steels you can find for knives. The corrosion resistance is not a big problem as long as you take care of it (clean and oil after use). So if you’re thinking of buying a HAP40 knife, we explicitly encourage you to do so!