Different Knife Metals
The type of metal will determine specifics on how to care for your knife. Knives are generally crafted of carbon steel or stainless steel. Carbon tends to remain sharper longer, but it also needs to be dried thoroughly after each use to prevent rust from forming. While stainless steel is not designed to rust, they don’t usually get as sharp as carbon. Plus, if you leave these knives in a drying rack or worse, soaking in a sink of soapy water, rust can happen.
The bottom line is know what metal your knife is crafted from. This allows you to provide the best possible care for your knife and extend the life of your tools for as long as possible.
Properties Of Knife Steel
Knife steel has a number of properties. Your basic understanding of these properties will help you to care for your knives so they give you many years of use. These following properties are some of the most important for users to know:
- Strength – the ability of the knife to resist applied forces, harder steel = stronger knife
- Hardness – how well the knife will resist damage, attained through heat-treating
- Edge Retention – the ability of the knife to hold its edge, which will determine how often the knife will need to be sharpened
- Wear Resistance – related to edge retention, this property measures the knife’s ability to resist damage and general wear from regular use
- Initial Sharpness – the sharpness of the blade when it is first removed from its packaging
- Corrosion Resistance – the likeliness of the blade to rust or corrode, which can be reduced with the addition of chromium to the metal
Knife Steel Alloy Additions
In some cases, different elements may be added to the steel during the melting process to change the properties of the metal and the knife. The following list gives you an idea of some of the alloys that might be added during the knife making process:
Chromium – This alloy makes the knife more resistant to corrosion and daily wear and tear. It can often be found in stainless steel sporting knives for this purpose and is also used in some kitchen cutlery to reduce corrosion.
Carbon – Although carbon is not technically an alloy, it can be added to knives to increase the hardness of the metal.
Nickel – Nickel is an alloy commonly used in some types of stainless steel to enhance toughness and corrosion resistance.
Molybdenum – This alloy is especially beneficial in improving the hardness of a knife and reducing the risk of damage like pitting.
Vanadium – An alloy that improves the grain structure of the metal, which in turn improves the wear resistance and toughness of the knife.
Popular Knife Steels
The ultimate in wear resistance and edge retention comes with Crucible’s CPM S90V steel. As you’d expect the carbon content is very high but the secret here is the extreme quantities of vanadium, almost three times that found in Elmax or S30V. Yes it’s ridiculously expensive, and yes it requires the patience of a saint to sharpen but nothing holds an edge or withstands abrasion quite like CPM S90V. Hold on to your hats though folks, because there’s a new contender gaining traction in the marketplace and that is S110V. More on that coming soon…
M390 is one of the new super steels on the block, manufactured by Bohler-Uddeholm (result of merger of Austrian Bohler and Swedish Uddeholm). It uses third generation powder metal technology and developed for knife blades requiring excellent corrosion resistance and very high hardness for excellent wear resistance. Chromium, molybdenum, vanadium, and tungsten are added to promote sharpness and outstanding edge retention. Unlike ZDP-189 most carbides are formed by vanadium and molybdenum, leaving more ‘free chromium’ to fight corrosion. M390 hardens to 60-62 HRC. Bohler calls this steel “Microclean” and it can be polished to achieve a true mirror. Moderately difficult to sharpen, but won’t take you as long as with S90V.
ZDP-189 by Hitachi is another of the newer super steels containing huge quantities of carbon and chromium that result in ridiculous levels of hardness. ZDP-189 averages around 64 HRC but some knifemakers are able to achieve upwards of 66 HRC. Of course with those levels of hardness you can expect superb edge retention but at the cost of extreme difficulty in sharpening. With a chromium content of around 20% you’d expect it to be immune to corrosion right? Wrong. The massive amount of carbon in ZDP-189 effectively ‘pairs up’ with the chromium to form carbides which leaves less ‘free chromium’ to battle corrosion. So, while it’s both harder and more wear resistant than S30V it’s more prone to corrosion.
European Uddeholm (now Bohler-Uddeholm) introduced Elmax which is a high chromium-vanadium-molybdenum alloyed powdered steel with extremely high wear and corrosion resistance. Elmax is stainless but acts in many ways like a carbon steel. You get superb edge holding and relatively easy sharpening while maintaining a healthy resistance to rust. The ‘best all round’ knife steel? Perhaps.
CPM-20CV is Crucible’s version of Bohler’s popular M390 steel which also influenced Carpenter to copycat with CTS-204P. As a Powder Metallurgy (PM) tool steel, you get a combination of impressive wear resistance and edge retention plus the added benefit of being highly corrosion resistant due to high levels of chromium.
CTS-XHP from US based Carpenter is another relatively new knife steel that has very good edge retention and hardens to about 61 HRC. This is yet another powder metallurgy creation where Carpenter’s technicians have developed an extremely fine powder grain that results in excellent performance. Slightly better edge retention than S30V and but a little more work required in the sharpening process. Think of CTS-XHP as a more corrosion resistant form of D2 steel with marginally superior edge retention. Like D2, however, it’s not easy to sharpen and can be brittle (prone to chipping).
A high performance tool steel which excels at toughness and arguably holds and edge better than any other carbon steel. Like all CPM steels, CPM M4 is created using Crucible’s patented Crucible Particle Metallurgy process, which provides an extremely homogeneous, stable and grindable product compared to the traditional processes. CPM M4 provides superbly balances levels of abrasion resistance and toughness through high doses of molybdenum (hence the “M”), vanadium and tungsten together with reasonably high levels of carbon. It can be hardened to around 62-64 HRC but note M4 is a carbon steel is not considered stainless with relatively low levels of chromium. So, while this is one of the best steels around for cutting, it has to be properly cared for and may develop a patina over time. Some manufacturers have resorted to coatings which do help but note they won’t last forever. Easy to sharpen?…erm, no.
In 2009, Crucible and Chris Reeve introduced an ever so slightly superior version of their excellent S30V steel and named it S35VN. By using a much finer grain structure and adding small quantities of niobium (hence the “N”) they were able to make the outstanding S30V easier to machine while improving toughness and ability to sharpen. In the real world, however you will find the two near-indistinguishable. Many would argue this is the ultimate in ‘mainstream’ knife steels and you would struggle to find any steel with better edge retention, toughness and stain resistance for the money.
Made by US based Crucible, CPM S30V (often simply referred to as S30V) steel has excellent edge retention and resists rust effortlessly. It was designed in the US and is typically used for the high-end premium pocket knives and expensive kitchen cutlery. The introduction of vanadium carbides brings extreme hardness into the steel alloy matrix. Dollar for dollar, this is generally regarded as one of the finest knife blade steels with the optimal balance of edge retention, hardness and toughness. Note S30V now has a slightly better looking brother in S35VN which is distinctly similar but easier for manufacturers to work with thanks to niobium. Still, S30V is pretty common these days and one of our favorites.
A relatively hard steel which is considered an upgraded version of 440C through the addition of Molybdenum. This achieves superior edge holding compared to 440C while retaining similar excellent levels of corrosion resistance despite having less Chromium. It has decent toughness good enough for most uses and holds an edge well. Not too difficult to sharpen with the right equipment. You’ll find a lot of quality pocket knives from top manufacturers like Benchmade using 154CM steel. You may also see CPM 154 which is a powder version of the same alloy produced much differently using Crucible Particle Metallurgy. The CPM process makes finer carbide particles resulting in a slightly superior steel with better edge retention … but whether the average user can tell the difference is arguable.
This steel can be thought of as the Japanese equivalent to the US made 154CM. Accordingly, it has very similar properties and characteristics to the 154CM and in general represents a high quality steel which has become very popular with knife makers. ATS-34 has great edge retention but is actually a little less rust resistant than the lower-range 440C steel.
D2 steel is a tool steel often referred to as “semi-stainless” as it falls just short of the required amount of chromium (13%) to qualify as full stainless yet it still provides a good amount of resistance to corrosion. On the flip side D2 steel is much harder than other steels in this category such as 154CM or ATS-34 and as a result holds its edge a little better. That said, it’s not as tough as many other steels and exponentially tougher to sharpen. In fact, you really need to be a master-sharpener to get a fine edge on D2.
The VG-10 steel is very similar to 154CM and ATS-34 with slightly more chromium for enhanced corrosion resistance but also contains vanadium which makes it marginally tougher than these two. It originated not too long ago from Japan and has been slowly introduced into the American market by respect knife makers like Spyderco. It’s really hard and can get extremely sharp but also somewhat brittle so prone to chipping.
H1 steel from Japan’s Myodo Metals is basically the ultimate in corrosion resistance and essentially does not rust. The epitome of true stainless steel. Naturally, this comes at a price and that price is edge retention which is relatively poor. So, while excellent for diving it’s a non-starter for most EDC use. Very expensive stuff.
N680 steel contains about 0.20% nitrogen and over 17% chromium making it extremely corrosion resistant. If your blade will be in frequent contact with salt water for example then this is the steel for you. It’s also a fine grained steel that can take a very fine edge. Consider it a cheaper alternative to H1 steel with decent edge retention but it won’t hold an edge as long as say, 154CM.
Once considered the high-end in US knife steels, 440C is a good all-round steel that has now been overshadowed by many of the newer super-steels on the block. This is a stainless steel commonly used on many mass-manufactured pocket knives and represents a solid affordable all-round choice. It’s reasonably tough and wear resistant but it really excels at stain resistance. Holds an edge better than it’s 400-series counterpart 420HC but at the expense of some corrosion resistance. The 440C blades can be sharpened relatively easily. It has the highest levels of carbon and chromium in this group.
AUS-8 steel is Japanese made and extremely similar to 440B steel which is slightly more resistant to rust and corrosion than 440C but less hard. It’s also similarly tough but may not hold its edge as well as some of the more premium steels which carry a greater degree of carbon. Remember, more carbon means more hardness and edge holding. Real easy to sharpen and takes a razor edge.
Created at Spyderco’s request, CTS-BD1 is a vacuum-melted stainless steel from US based Carpenter that is often likened to AUS-8 and 8Cr13MoV with many putting it slightly ahead of those two based on superior edge holding. With slightly more chromium it also achieves better corrosion resistance. As a fine grain steel with smaller carbides (hard, wear resisting particles) it takes an edge relatively easily but won’t hold an edge as long as larger carbide steels like VG-10.
The MoV (or Cr) series of steels originate from China and comparable to AUS-8 but containing slightly higher carbon content. You typically get great value for money with this steel and good manufacturers like Spyderco have mastered the heat treatment process to bring out its best.
The 14C28N stainless steel from Swedish manufacturer Sandvik is considered an upgrade to their 13C26 described below. In fact, Kershaw asked Sandvik to make their 13C26 steel more resistant to corrosion and the result was 14C28N. In the lab you’ll find slightly more chromium and less carbon in the 14C28N but the real secret is the addition of Nitrogen which promotes corrosion resistance. Overall a very impressive mid-range steel that can be made extremely sharp. Quite possibly the best steel you’ll find on a sub-$30 production knife.
Very much like 420HC but with slightly more carbon which results in enhanced levels of wear resistance and edge retention but suffers from weaker anti-corrosion properties.
Generally considered the king of the 420 steels, 420HC is similar to 420 steel but with increased levels of carbon (HC stands for High Carbon) which makes the steel harder. Still considered a lower-mid range steel but the more competent manufacturers (e.g. Buck) can really bring out the best in this affordable steel using quality heat treatments. That results in better edge retention and resistance to corrosion. In fact, this is one of the most corrosion resistant steels out there, despite it’s low cost.
This is Sandvik’s version of the AEB-L steel, originally developed for razor blades. Close comparison to 440A steel with a higher carbon to chromium ratio making it generally a little harder and wearable at the expense of corrosion resistance. Still, in real world applications it’s difficult to tell them apart and they tend to perform very similarly. Sandvik later came out with 14C28N which is a slightly improved version of 13C26.
This is the most popular 10-series standard carbon steel (about 1% carbon) with low corrosion resistance and average edge retention properties. Why would you want 1095 steel? The appeal here is 1095 is a tough steel that’s resistant to chipping, it’s easy to sharpen, takes a crazy sharp edge and is inexpensive to produce. This makes it desirable for larger heavy duty fixed blades and survival knives which are going to be subject to more abuse than your typical EDC. Many manufacturers will coat their 1095 knives to delay the onset of any corrosion but a simple oil treatment will do the trick.
420 & 420J
The 420 steel is on the lower end of the quality spectrum but still perfectly fine for general use applications. It has a relatively low carbon content (usually less than 0.5%) which makes for a softer blade and as a result will tend to lose it’s edge quicker than higher end steels. Blades made from 420 steel will rapidly lose their sharp edge over a relatively short time period. That said, it’s typically tough with high flexibility and extremely stain resistant but it is not particularly resistant to wear and tear. As you would expect, knives made from this type of steel are generally low priced, mass produced items.
Japanese made equivalent to the 420 series steel. A soft steel that’s generally low quality with relatively little carbon content but it is very resistant to corrosion.
Knife Steel Performance Charts
Here are my rankings for edge retention, corrosion resistance, Rockwell hardness and wear resistance.
What about Damascus steel?
Damascus steel originates from the middle east from countries like India and Pakistan where it was first used back in good old “BC” times. It’s instantly recognizable as it bears a swirling pattern caused by the welding of two different steels and so often referred to as “pattern-welded” steel (not to be confused with Wootz steel which is only similar in appearance). There are many myths about the strength and capabilities of Damascus steel but today it is largely popular because of its aesthetic beauty. Mostly for collectors only.
Remember, blade steel is not everything. Knife buyers should beware getting caught up in researching the perfect steel type as it is not by itself the only thing that dictates how a knife will perform. Steel analysis has become somewhat scientific that it’s easy to get caught up in the maze of statistics. Note – just because a blade is made from the premium or high-end steels listed above does not automatically mean it’s “better” than the lesser steels. The heat treatment techniques used by the manufacturer as well as the design of the blade itself play a huge role in the ultimate outcome of knife performance!
In reality, all modern steels will perform well enough for most users so consider spending more time on other aspects of the pocket knife such as how the knife handles and other features.