CPM S35VN Steel Review
Chris Reeve Knives Pacific
When Crucible Industries introduced its CPM S30V steel, blade-smiths and knife-lovers alike fell in love with it; the quality wear resistance, toughness, and machinability offered by the steel was equal to none other. People were calling it, “the best knife steel available,” and indeed, it might have been. Until Crucible Industries announced that they were coming out with a newer, improved version of their premium grade knife steel- CPM S35VN, which would have an increased toughness and ease of sharpening over its predecessor. Soon it became clear that S35VN steel was a top-grade steel to rival the best in its class.
What is S35VN steel and how does it differ from S30V?
CPM S35VN is a quality stainless steel that is part of Crucible Industries’ “SxxV series”. “CPM” identifies the steel as having been made through Crucible Industries’ CPM process, offering an improved outcome over that of conventional melting practices. The letters “S,” “V,” and “N” refer to the terms “stainless,” vanadium,” and “niobium,” respectively. The number thirty-five has no significance other than to differentiate between S30V steel.
S35VN steel is composed of 1.4 percent carbon, 14 percent chromium, 3 percent vanadium, 2 percent molybdenum, and .5 percent niobium. Carbon is the most essential element in the hardness of steel; the higher the carbon content, the harder the knife is. When combined with other alloys including chromium and vanadium, carbides are formed which are harder than just the carbon alone. This carbon content is very similar to that of the S30V type, which contains 1.45 percent carbon.
With the newer steel, however, a small bit of a carbide called niobium was introduced in the place of some of the steel’s vanadium content, an innovative and critically altering change that sets S35VN steel apart from its predecessor and many other steels. The niobium, combined with the carbon, makes this steel 15 to 20 percent tougher than S30V.
Despite the high level of toughness in this steel, which usually diminishes a steel’s wear resistance, this steel does not lose out on a superior resistance to wear and chipping. Combined with carbon, the niobium carbides make the steel more effective in providing resistance to wear and edge chipping than if it were more dependent on chromium, which is the case with many other steels. The resulting edge holding ability of this steel is remarkable, ensuring S35VN steel to be a long lasting one.
Vanadium, as well, is essential to balance S35VN’s toughness with its wear resistance. Not only does it increase strength and toughness, but it also promotes fine grain structure and forms hard carbides that dramatically intensify edge holding. Molybdenum is yet another key component of this steel’s wear resistance, as the harder the steel is, the stiffer it becomes. Molybdenum combines with carbon to make hard carbides that take that problem out of the equation. For these reasons, S35VN steel offers a superior edge retention over conventional high chromium steels such as 440C and D2 steels.
Despite being less reliant on chromium, the carbide is still crucial for the high quality performance of the steel. Chromium is a critical ingredient to increase a steel’s stain resistance, and despite not being on par with niobium and vanadium in terms of wear resistance, chromium still helps add to a steel’s wear resistance, and is still every bit as important as S35VN’s other ingredients.
This composition allows for S35VN steel to be an incredibly hard, high quality steel offering superior dimensional stability, grindability, and toughness that together make this a top grade steel at the top of its class.
What is the CPM process?
Crucible Industries’ famous CPM process is one that is used to make various types of high quality steel, with its users claiming its methods to be far superior to those of conventional melting practices. The CPM process creates a steel powder using a process called gas atomization, where molten steel is atomized (separated into atoms) by inert gas jets, and then cools down to perfectly spherical shaped powder particles with a high cleanliness level. The powder is then combined through the HIP process into 100 percent dense compacts. These compacts are then processed into bars through a mill.
The properties received by steels that are produced through this process are said to be far greater than those of conventionally melted steels, offering improved wear and corrosion resistance, toughness, and machinability. In addition, this method allows for the manufacturing of alloys with unique or enhanced properties that cannot be made with traditional steelmaking methods.
Knives made with S35VN steel can be used for various purposes. Thanks to its high grade toughness and ability to become razor sharp, it is ideal for use in hunting and bushcraft knives, where toughness and wear-resistance are key. Knives using this steel will surely perform even under the often less-than-ideal conditions found outdoors. For avid woodsmen, campers, and hunters, you will want a knife that provides an impressive, quality knife experience but also will not let you down where knives with other steels might. If you are frequently found outdoors in rainy, muddy, and otherwise dangerous conditions, than so will your knife. The rugged dependability offered by S35VN steel in less-than-ideal conditions makes it quite obvious why one would want it in their knives.
Moreover, this type of steel can be found in cutlery and chef’s knives, for even in the kitchen, where despite situations being less dangerous, quality in a knife is certainly never a bad thing, and as far as kitchen knives are concerned, S35VN is the steel to use.
How did it score?
The Charpy V-Notch test measures the foot-pounds required to break samples of specific steels at given temperatures and predetermined hardness. At a Rockwell RC hardness level of 58, it took 32 foot pounds of force to break the S35VN sample, higher than all of the other steels tested, including CPM S30V (at 58 HRC), S60V (at 56 HRC), S90V (at 58HRC), and 154 (at 60HRC), 420HC (at 58 HRC), and M390 (at 60 HRC) steels. This test measured each steel’s longitudinal toughness.
In regard to transversetoughness, a Charpy C-Notch Test study revealed both CPM steels- S35VN and S30V- to be far superior to the other knife steels tested. S35VN holds a transversal resistance of up to an impact energy of 12 pounds, with S30V two pounds down at 10 pounds. The other steels tested, 145CM and 440C grade steels, scored almost 5 times lower than S35VN, both at just 2.5 pounds of resistance. These results indicate that the CPM steels are much more resistant to chipping and breaking when used for jobs which require side loading. This makes these steels especially good for use in bigger blades.
The results of a CATRA (Cutlery Allied Trades Research Association) edge retention test put this steel at Rockwell RC hardness levels on par with top grade steels such as Bohler’s M390 and N690, Uddenholm’s ELMAX, and Peachey’s A2 steel. On CATRA’s TCC (total cut cards) test, where the number of impregnated silicon cards cut by blades with each steel type are measured, S35VN scored a 707, higher than many steels including N690, A2, and 3V, while lower than others including ELMAX and M390.
In addition to tests, S35VN steel used in various knives has won those knives numerous awards. Chris Reeves’s Galvin and Hawk designed TI-LOCK knife won the “Overall Knife of the Year” award in 2010, using none other than S35VN steel.
Blade Magazine’s 2012 “American Made Knife of the Year” award went to Microtech’s Socom Delta, a superb, quality knife made of S35VN steel.
The test results and awards won by S35VN and knives using it confirm, or at least give a certain amount of validity to, the claims praising S35VN to be the “the best blade steel available,” and “the ultimate cutlery steel.” Before all of the comparisons and the questions of “which is better”, the facts clearly show that S35VN steel is truly a top-tier, high-quality knife steel offering superior toughness, wear resistance, edge retention, and machinability to please and impress both knife lovers and knife makers. Whether used for hunting, camping, or cooking, this steel will ensure not only performance to the highest standards of toughness and durability, but also a pleasing knife experience offered by only the best steels around.
How does it compare with other high-grade knife steels?
Questions like these are frequently asked regarding every type of steel: “which one is the best?” “Is steel A better than steel B?” “Should I choose this knife over the other because of its steel content?” Similarly, with S35VN, questions have been raised regarding how it stacks up against the other steels in its class.
CPM 154 Steel
CPM 154 steel is a high chromium stainless steel knife, boasting a hardness, corrosion resistance, and edge retention superior to that of other steels such as 440C and D2 steels. When made with the Crucible Industries’ CPM process, it offers an even more improved toughness, machinability, and tool performance. However, when pitted against S35VN steel, its results are less impressive. S35VN is a more advanced steel, with vanadium and niobium carbides to improve its toughness and wear resistance. The simpler 154 steel is composed of only carbon, molybdenum, and chromium, and therefore cannot offer an equal extent of the toughness and wear resistance provided by these innovative carbides. For these reasons, knives using CPM 154 or 154 CM steel will not be as expensive as those with S35VN steel.
There has been a lot of hype recently about ELMAX steel. The claims stating it to be a superior “super-steel,” are more than true, as ELMAX steel continues to impress all who use it. Many of those who use it will say that it is far superior to S35VN steel. ELMAX steel has a sophisticated composition, containing carbon, chromium, manganese, molybdenum, silicon, and vanadium. This composition allows for it to have an incredibly high wear and corrosion resistance, as well as hardness and a remarkable dimensional stability.
ELMAX does not contain niobium, a key ingredient to S35VN, but displays a superior dependability at a high HRC than S35VN, with a better high corrosion resistance all while retaining its toughness. ELMAX is produced using a particle-metallurgy process, similar to CPM, but many will argue that CPM yields better results, giving its steels the edge of an improved wear-resistance and grindability. Powder-metallurgy and other conventional steel making processes are prone to segregation, where non-uniform clusters of a steel’s carbides persevere as remnants of the as-cast microstructure. This segregation of alloys can negatively affect the steel’s production and performance. The CPM process, however, creates a uniform distribution of carbide clusters, and completely removes the threat of segregation.
Knives containing both of these steels are far from inexpensive, with folding knives in the price range of 130-200 and over.
Bohler’s M390 is not very different from ELMAX; it is extremely anti-corrosive, very finely grained, and very pure. Like ELMAX, it is just as tough as, if not tougher than, S35VN, and can hold an extremely strong and sharp edge. ON CATRA’s TCC test, M390 scored higher than S35VN, at 959, whereas S35Vn scored a 707. Yet on Charpy’s C-Notch test, S35VN resisted up to an impressive 32 foot pounds, with M390 falling significantly shorter at just 22 foot pounds. In addition, welders may note that M390 is considerably harder to temper than S35VN, which can affect its machinability. In addition, the latter steel can offer a superior damage resistance, a very desirable trait in a knife.
M390 steel is also slightly more expensive than S35VN, with the price for an average folding knife hovering around the 200 dollar range, whereas one can find a good S35VN folding knife for as low as 130 dollars, although its price can go up to 200 dollars or more.
Notable knives with the S35VN
S35VN steel has been used in myriads of different knives serving numerous different purposes. As far as the common folding knife is concerned, we have chosen a few notable knives containing this high-grade stainless steel.
Zero Tolerance ZT 0550
This US made, Kershaw Zero Tolerance folding knife is popular for many reasons, one of which being the use of S35VN steel for its blade. This folding knife, designed by Rick Hinderer, is 8.125 inches when fully extended, with a closed length of 4.63 inches and a blade length of 3.5 inches. Its handle is an ergonomic one of textured G-10 material and there is a convenient loop for carrying convenience. It is slightly heavy for its size, at 5.8 ounces, but will serve its purpose well, with the quality features offered by its steel, features which speak for themselves. The knife is on the medium to more expensive side at 172 dollars, but if you are looking for the quality offered by the knife, and it is in your price range, then this knife is ideal for you. Simple but powerful in an elegant way, this knife will serve its purposes to the highest degree, and will please you with its quality results.
Spyderco Paramiltary II
Spyderco’s limited edition S35VN Paramilitary model is convenient as well as it is tough, with an ergonomic, G-10 handle, a lanyard hole, and a 4-way, reversible pocket clip to sit comfortably in your pocket. The entire knife is 8.28 inches, with a blade length of 3.44 inches and a closed length of 4.81 inches. In addition, the blade is very light, at a mere 3.75 ounces. At a price of 180 dollars, you are definitely paying for the superior quality and features that come with any knife of S35VN.
Many high end knife makers use CPM-S35VN. The list includes luminaries such as Benchmade, Chris Reeve Knives, Spyderco, ProTech Knives, and Boker to name a few. Whether you are looking to buy a knife with S35VN steel or looking to make one, it is quite obvious that this high-end grade steel will perform to the highest quality in regard to toughness, wear-resistance, and machinability, providing a pleasant and outstanding experience for both knife makers and knife users.