Blade Steel

CPM-M4 - Blade Steel

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Steel Composition

carbon 1.42 %
chromium 4.00 %
molybdenum 5.50 %
vanadium 4.00 %
manganese 0.30 %
silicon 0.25 %
tungsten 5.50 %

Often referred to as CPM M4, this high-speed steel is produced by Crucible Industries, renowned for its unparalleled hardness and outstanding wear resistance. CPM M4 is a top choice for competition cutters due to its excellent edge retention and toughness. This steel often considered as a bridge between stainless and high carbon steels.

Advantages of CPM-M4 as Knife Steel

The CPM M4 blade steel offers exceptional edge retention, even in extreme conditions, requiring less frequent sharpening. It's a popular choice for high-performance cutting competitions, as the blade remains sharp even after continuous use. Another advantage is its excellent toughness, making it durable for heavier tasks.

This steel's robust structure resists damage and fracturing even when subjected to intense forces, making it desirable for professional-use knives and tools.

Disadvantages of CPM-M4 for Knives

One of the main drawbacks of CPM M4 is its moderate corrosion resistance - it's not stainless. Regular maintenance is required to prevent rust and oxidation, especially in humid environments. Some knife users might also find it challenging to sharpen due to its high hardness.

Steel Rating

Steels with good edge retention will stay sharp longer, reducing the need for frequent sharpening

Edge Retention

5/6 Points

Toughness is the steel's ability to absorb energy and deform without breaking


4/6 Points

Corrosion Resistance measures how well the steel can resist rust and oxidation

Corrosion Resistance

2/6 Points

Sharpenability refers to how easily a knife blade can be sharpened to its desired edge


2/6 Points

This is a relative measure based on typical market values. The actual price can vary widel


2/6 Points

A higher HRC number typically indicates a harder steel, which can hold a sharper edge


64 - 66 HRC
Please be aware that this rating should be understood as a comparative measure. It's simply a rough estimation in relation to other knife steels.

Is CPM-M4 Rust Resistant?

CPM M4 is not a stainless steel and has only moderate corrosion resistance. Thus, regular cleaning, drying, and oiling are necessary to prevent rust, particularly when using the knife in wet conditions or storing it for extended periods.

How Durable is CPM-M4?

With a high HRC rating ranging from 64 to 66, CPM M4 is one of the hardest knife steels available. This high hardness level results in excellent edge retention and wear resistance but might pose some difficulties during sharpening. Nevertheless, the benefits of this hardness are seen in regular heavy-duty use where the blade performs without dulling quickly.


The reputation of CPM M4 is one of high-grade cutting performance. It's widely used in high-end knives and recognized for its superb edge retention and durability. This steel is a common choice among professionals who demand performance, such as chefs and hunters. Its premium reputation, however, places it at a higher price point.


In conclusion, CPM M4 represents a premium choice in knife steels, providing incredible hardness, exceptional edge retention, and impressive toughness. Its requirement for regular maintenance to prevent rust isn't a deterring factor for users who value performance over convenience. While being on the costly side, CPM M4 for EDC Knives offers great value for money given its superior performance characteristics.