A comparison of powder steels: which is best for your knife?

Powder steel does not automatically mean that one knife is better than all the others. Individual materials are designed with different priorities. Some offer a balanced combination of sharpness, toughness and easy maintenance, while others focus on maximum hardness or exceptionally long edge retention.

For an ordinary customer, names such as SG2, ZDP-189, HAP-40, Böhler M390 Microclean or CPM S35VN may look like an incomprehensible string of abbreviations. That is why we will explain what each steel actually brings to kitchen work, who it is suitable for and what kind of care it requires.

What is powder steel?

In conventional production, molten steel is cast into a larger billet, which is then processed. In powder metallurgy, the molten alloy is first atomised into very fine droplets. These rapidly solidify and form metal powder.

The powder is then compacted and bonded at high temperature into a solid material. Further processing follows, such as forging and rolling. The result can be a finer and more uniform microstructure with better distributed alloying elements and carbides.

Powder metallurgy, however, is not a magic term that by itself guarantees a perfect knife. The result also depends on heat treatment, blade geometry, material thickness behind the edge, grind and final sharpening.

What does HRC hardness mean?

HRC is a hardness value measured using the Rockwell method. For kitchen knives, it gives a simplified indication of how well the blade can resist deformation. Higher HRC usually makes it possible to create a finer edge and extend its retention, but at the same time it can increase the edge's sensitivity to lateral stress and rough handling.

Overview of powder steels and HRC ranges

The following values represent approximate ranges used in finished knives or recommended during heat treatment. A specific knife may have a different hardness depending on the manufacturer's intended design.

Individual powder steels in detail

CPM S35VN – balanced and tough

American CPM S35VN offers a good balance between edge retention, corrosion resistance and toughness. Compared with the hardest Japanese powder steels, it generally does not hold an edge for quite as long, but it handles normal use better and is usually easier to sharpen.

It is suitable for customers who want a high-performance and practical kitchen knife but do not need to chase maximum hardness. The approximate range is around 58–61 HRC.

BG-42 – clean and proven stainless steel

BG-42 was developed as a highly clean steel for demanding technical applications. In knives, it offers a fine edge, good wear resistance and practical corrosion resistance. Depending on heat treatment, blade hardness is approximately 59–62 HRC.

It is suitable for demanding home cooks who want high performance without extreme hardness.

MD606 – a more affordable entry into powder steels

MD606 is used as a high-performance core in three-layer kitchen knives. Manufacturers specify a hardness of approximately 60–63 HRC. It offers long edge retention, a fine structure and good corrosion resistance.

Because its exact chemical composition is not publicly standardised as well as that of better-known steels, it is important to assess primarily the specific knife, its manufacturer and heat treatment.

Böhler M390 Microclean – wear and corrosion resistance

Austrian Böhler M390 Microclean is a powder-metallurgy martensitic chromium steel with very high wear resistance and good corrosion resistance. The manufacturer also approves it for contact with food.

In knives, it is often treated to approximately 60–62 HRC. It is suitable for customers who want long edge retention and a practical stainless blade. Because of the hard vanadium carbides, quality abrasives are recommended for sharpening, ideally diamond or high-performance ceramic stones.

SG2 / SPG2® – versatile premium choice

Super Gold 2 is one of the best-known Japanese powder steels used in kitchen knives. Takefu Special Steel uses the official designation SPG2®; in commercial knife names you will also commonly encounter the abbreviation SG2.

The material combines high hardness, wear resistance, toughness and corrosion resistance. Official materials specify a hardness of at least 62 HRC, while finished knives typically fall approximately within the range of 60–64 HRC, depending on the manufacturer.

SG2 is suitable for cooks who want premium cutting performance and long edge retention while still requiring a practical stainless blade.

SPG STRIX® – high hardness with an emphasis on sharpenability

SPG STRIX® is a separate modern powder steel from Takefu Special Steel. It is not simply another name for SG2. The manufacturer uses a Strong Matrix concept that focuses on strengthening the metallic matrix itself rather than relying only on a high proportion of extremely hard carbides.

The result is a hardness of around 65 HRC, a very fine edge and, according to the manufacturer, more favourable sharpenability than some carbide-rich powder steels of similar hardness.

It is intended for demanding users who want a modern stainless steel with high hardness but do not want sharpening to be unnecessarily difficult.

HAP-40 – exceptional edge retention

HAP-40 is a Japanese powder high-speed steel developed for cutting tools. The term “high-speed” does not mean that it will automatically make you cut faster in the kitchen. It describes the original technical category of the material.

Depending on the selected hardening regime, Proterial specifies a hardness of approximately 64–68 HRC. Kitchen knives commonly fall around 65–66 HRC. The advantage is exceptional wear resistance and very long edge retention.

HAP-40, however, is not a conventional fully stainless kitchen steel. It requires more careful washing, immediate drying and protection from moisture. It is suitable for experienced cooks who prioritise performance over carefree maintenance.

ZDP-189 – extreme hardness for experienced users

Japanese ZDP-189 contains approximately 3% carbon and 20% chromium. Proterial specifies a hardness exceeding 65 HRC after hardening; finished knives typically fall approximately between 64–67 HRC.

This steel offers exceptional edge retention and high wear resistance. The reward is long-lasting cutting performance, while the disadvantages are more demanding sharpening and greater sensitivity of the fine edge to impacts, twisting or prying.

ZDP-189 is intended for experienced users who know how to handle a hard Japanese knife, use the correct cutting board and want the longest possible interval between sharpening.

How to choose a powder steel according to your cooking style?

What has a greater influence on cutting performance than the name of the steel?

Steel is important, but when cutting, the customer experiences the entire knife. A thick blade made from a top steel can create more resistance than a thin, well-ground blade made from a less prestigious material.

1. Blade geometry – thickness and the way the blade tapers towards the edge.
2. Thickness behind the edge – significantly affects resistance when passing through food.
3. Heat treatment – determines the actual hardness, toughness and stability of the steel.
4. Sharpening quality – determines sharpness and the cleanliness of the resulting cut.
5. Knife shape and balance – affect control, hand fatigue and suitability for a particular working style.

That is why we recommend choosing the whole knife, not just a steel abbreviation or the highest HRC number.

Sharpening powder steels

The higher the steel's wear resistance, the more slowly material is removed during sharpening. With steels containing a high proportion of hard vanadium carbides, an ordinary soft sharpening stone may work slowly or wear out quickly.

For steels such as M390, ZDP-189 or HAP-40, we recommend quality water, ceramic or diamond stones. Avoid cheap pull-through sharpeners with aggressive wheels, which can unnecessarily remove material from a fine edge.

Choose sharpening stones and accessories

How to care for a powder steel knife?

• Always wash the knife by hand and dry it immediately after washing.
• Do not use glass, stone or ceramic cutting boards.
• Do not chop bones, joints, hard pits or frozen foods.
• Do not twist the blade inside food or use it for prying.
• Protect the edge with a sheath, knife block or suitable magnetic strip.
• With HAP-40, pay extra attention to protection against moisture and acidic foods.

Conclusion: there is no single best powder steel

If you are looking for a versatile premium kitchen knife, SG2/SPG2 offers one of the most balanced combinations of properties. CPM S35VN will appeal to customers who prefer toughness, while M390 stands out for corrosion resistance and wear resistance.

For exceptionally long edge retention, HAP-40 and ZDP-189 are interesting choices, but they require more experienced handling. Modern SPG STRIX® represents a technologically interesting route to high hardness while maintaining favourable sharpenability.

The best choice is therefore not the steel with the highest HRC. It is the steel whose properties match your cooking style, experience, willingness to maintain the knife and sharpening method.

Frequently asked questions about powder steels

What is powder steel?

It is steel produced from rapidly solidified metal powder, which is subsequently compacted into a solid material. The process makes it possible to create a fine and uniform microstructure.

Is powder steel always better than conventional steel?

No. It offers broad possibilities in composition and high performance, but knife quality also depends on heat treatment, geometry, grind and final sharpening.

What does HRC hardness mean?

HRC expresses steel hardness according to the Rockwell scale. A higher value can support edge retention, but it usually also increases the need for proper handling.

Which powder steel holds an edge the longest?

ZDP-189 and HAP-40 are among the materials with exceptional edge retention. The result is also influenced by hardness, geometry, sharpening method, cutting board and working technique.

Which powder steel is best for an ordinary kitchen?

SG2/SPG2 offers a very good balance between edge retention, corrosion resistance and everyday usability. CPM S35VN may be suitable if greater toughness is preferred.

Is SG2 the same as SPG STRIX?

No. SPG STRIX® is a separate and newer steel from Takefu Special Steel. It uses a different metallurgical concept and is not simply renamed SG2.

Is SG2 the same as SPG2?

SG2 is a widely used commercial designation for Super Gold 2. Takefu Special Steel uses the official registered designation SPG2® for this material.

Is HAP-40 stainless steel?

HAP-40 is generally described as a semi-stainless powder high-speed steel. It is more corrosion resistant than conventional carbon steel, but requires more careful drying than fully stainless materials.

Which powder steel offers the best corrosion resistance?

Böhler M390 Microclean offers very good corrosion resistance. Stainless steels SG2 and CPM S35VN are also practical for kitchen use, but they still need to be washed and dried after use.

Why are very hard steels more difficult to sharpen?

The reason is not just HRC, but also the amount, size and hardness of the carbides. Steel with a high proportion of hard vanadium carbides may require a more powerful abrasive.

Can a powder steel knife go in the dishwasher?

No. A dishwasher can damage the edge, blade surface and handle material. Always wash a quality kitchen knife by hand and dry it immediately.

What cutting board is suitable for hard powder steel?

A quality wooden or edge-friendly synthetic cutting board is best. Glass, ceramic, stone and metal quickly dull or damage a fine edge.