CPM S30V Steel

Brief background

When choosing any knife, steel is one of the key factors that determines sharpness, toughness, wear resistance, and corrosion resistance. One of these knife steels is CPM S30V steel.

CPM S30V steel is a premium-grade stainless vanadium powder steel created using a patented technology in 2001 by Crucible Industries with the participation of several knife makers such as Chris Reeve, Dirk Barber, Phil Wilson, Sal Glesser, Ernest Emerson, Tony Marfione, William W. Harsey Jr., Tom Mayo, Jerry Hossom, and Paul Bos, specifically for the production of knives.

The result of the development was a knife steel with a balanced composition, which promotes even distribution of vanadium carbides during heat treatment at a hardness level up to 61 HRC, to achieve optimal mechanical properties of knife blades intended for heavy-duty use.

Compared to some other steels, blades made from CPM S30V steel have the following notable features: small grain size, improved impact toughness, fairly high break resistance, resistance to chipping and fractures, and quite good corrosion resistance. This steel is also relatively easy to sharpen.

Crucible Industries has been a major player in the knife steel industry for decades thanks to steels such as 154CM, developed in the late 1950s and popularized by Bob Loveless in the early 1970s.

The company is especially known for the development and production of powder steels using the patented CPM (Crucible Particle Metallurgy) process, which began to be produced in large volumes in the 1970s.

One of the distinctive aspects of producing all powder steels is that the manufacturing process allows for introducing a higher amount of alloying elements without reducing toughness or workability. The production of powder steel achieves a very high material uniformity. This technology makes it possible to produce high-alloy steels with finer microstructures thanks to the rapid solidification process.

In many ways, the arrival of a steel like S30V steel became an important milestone in the development of knife steels and an innovative answer to the growing demand for knives with blades made from high-quality steel that can maintain a stable cutting edge and resist corrosion.

Crucible has also created a whole range of other powder steels, including S35VN, S45VN, S60V, and S90V, but none of them saw particularly widespread use in knife production in the long run.

CPM S30V steel composition. Chemical and physical properties of alloying elements

Along with 1.45% carbon, the three main alloying elements of CPM S30V steel are 14% chromium, 4% vanadium, and 2% molybdenum.

The carbon content in CPM S30V steel can be considered quite high to provide the blade with sufficient hardness and toughness, and in combination with other alloying metals, to impart the necessary mechanical properties.

Chromium content of 14% in the composition increases hardness, tensile strength, and density. Significant corrosion resistance generally appears with chromium levels above 13%, making the alloy stainless.

Chromium, as an alloying element in iron, lowers the critical cooling rate, increases wear resistance and heat resistance. It strengthens the steel and helps form carbides. When the alloy contains around 13% chromium, corrosion resistance increases sharply, which is why it is used for producing stainless steels—or, in more technical terms, such steel is more correctly referred to as conditionally stainless. In addition, chromium stabilizes ferritic compounds and phase shifts in the alloy.

In terms of processing, chromium also has some downsides—it can reduce impact toughness and forgeability or weldability. On the other hand, chromium definitely reduces thermal conductivity, which in turn shifts the heat-treatment temperature curve to a different range.

When chromium is present in the alloy, the steel can be hardened in air or oil. Chromium carbides help maintain sharpness, wear resistance, and heat resistance.

Vanadium in steel alloys increases toughness, wear resistance, density, and strength. Its presence also improves corrosion resistance and increases the oxide layer. Vanadium carbide inclusions are extremely hard.

In combination with carbon, vanadium forms its own carbides, which improve wear resistance, strength, and hardness. Even a small amount of vanadium can prevent the formation of large grains. After hardening and tempering, reheat treatment becomes very difficult. Compared to several other steels, the vanadium content of 4.00% in the alloy is quite high and has a significant positive effect on the mechanical properties of knife blades.

Structurally, powder steels, including CPM S30V steel, consist of martensite, carbides, and various non-metallic inclusions. Although the martensitic structure of powder steel is very hard and brittle, the finer grain, high density, and uniform carbide distribution ensure very high performance characteristics.

Molybdenum is one of the important components of the CPM S30V steel alloy. Molybdenum is a transition metal that, due to its silvery-white sheen, was often mistaken for lead in the past. Today, it is an important alloying element in the steel industry and is used in combination with other alloying agents.

In steel alloys, molybdenum increases hardness, tensile strength, and weldability. On the other hand, it reduces forgeability and ductility.

Molybdenum improves the tempering process after hardening and enhances the effect of other alloying elements, which is why it is used in combination. Like some other alloying elements, molybdenum bonds with carbon to form its own carbides, which in turn increase steel hardness and corrosion resistance.

The presence of molybdenum at 2.00% in the alloy, taking into account other alloying metals, is fully justified and has proven itself in practice.

CPM-S30V composition spreadsheet

Features of CPM S30V steel

As already mentioned above, one of the main distinguishing features of powder steels, and in particular CPM S30V steel, is the much finer grain structure, which in turn improves almost all performance metrics and provides undeniable advantages in use compared to simpler steels.

Comparison of S30V steel vs other steels in the Crucible lineup

To understand the advantages of CPM S30V steel, it is first worth reviewing some data from other steels produced by Crucible.

154CM steel, as the predecessor of several steels from the company, is more corrosion-resistant, more ductile, and has greater corrosion resistance potential than S30V. In other respects, S30V steel offers a much higher level of edge retention.

D2 and S30V steels are both high-grade steels. The differences in composition and performance come down to this: D2 has higher wear resistance, while S30V steel has significantly higher corrosion resistance, better toughness, and is therefore more difficult to sharpen.

Both CPM 20CV and S30V are powder steels from the company, with the difference being that 20CV surpasses S30V in toughness and edge retention due to its higher chromium content. On the other hand, S30V steel offers a more balanced combination of all characteristics, with slightly lower values, but adds considerable corrosion resistance, better overall balance, and is somewhat easier to sharpen.

As already noted above, compared to CPM S35VN and CPM S45VN, S30V steel wins in terms of the combination of all characteristics along with corrosion resistance, while both these steels have slightly better edge retention and higher impact toughness. Both steels are equally resistant to corrosion and have good wear resistance. They are also easier to sharpen than S30V steel.

A minor drawback of CPM S45VN may be its relatively small model range and the highest price among these three steels.

When considering the super steel class, S60V and S90V belong in this category. Both of these steels significantly outperform S30V steel and many others. Thanks to their high carbon and vanadium content, knife blades become extremely wear-resistant, but they are also quite difficult to sharpen. In addition, such steels are prone to chipping with improper use, and knives made from them are rather expensive. While it is certainly possible to use knives with blades made from these steels, S30V steel, at a much lower price, is no less effective, strong enough, and resistant.

Sharpening characteristics of CPM S30V steel

When sharpening blades made from CPM S30V steel with a standard heat treatment at 58–60 HRC, there are generally no issues — one can use a wide range of industrial abrasives, for example TSPROF CS series.
If the hardness level is above 60 HRC, it is perfectly reasonable to use various ready-made solutions in the form of diamond stones on different bonding agents, such as TSPROF Alpha resin bonded diamond stones.

Conclusions

Every person’s impressions of using a knife with CPM S30V steel on the blade will also be different. In addition, you can simply take your own knife made of this steel, cut something, and you will clearly understand that much depends not only on the specifics of the steel’s heat treatment and the size and parameters of the blade itself, but also on the shape of the handle, its ergonomics, and your personal feel.

Overall, CPM S30V steel is a very well-balanced powder steel with good edge retention. The steel can withstand moderate lateral loads and resists moisture well. Even though many American knife companies are switching to newer powder steel options, CPM S30V steel remains today a good choice and shows good performance on knives released earlier.

It should be noted that if the processing quality of CPM S30V steel is high enough, sharpening this steel will not present significant problems, but if the steel is over-tempered, some sharpening difficulties may arise.

Among the most well-known knife brands and models in this steel are Spyderco with the Military 2 model and Buck with the Buck 110, although the latter with CPM S30V steel is considered a limited edition.

The reader can use this article as a sort of guide, but is also free to decide for themselves, based on personal experience and the experience of friends or acquaintances who own knives made from this steel.

A sharpener that can handle any knife made of any steel? A TSPROF Pioneer. This guided system offers unmatched precision, adjustable angles, and compatibility with various abrasives, ensuring top-tier edge quality. Durable construction and user-friendly design make it perfect for sharpening knives made of CPM S30V steel.