Bushcraft Knives from Casstrom of Sweden
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Steel Information

High Carbon Steels


1095 was developed as a simple tool steel that proved very effective for knife blades when heat treated appropriately. The high carbon content allows the steel to be quenched to a hardness of HRc66, but for knife blades the steel is usually drawn back (tempered) to 56-58 HRc, which provides an optimum combination of hardness and toughness.0.95C 0.4Mn

O2 (K720)

Böhler Tool Steel K720 (O2) is a very tough and strong oil hardened high carbon tool steel. The chemical composition allows it to be hardened to a high degree whilst maintaining ductility and toughness at the same time as it is easy to sharpen and can obtain a razor sharp edge. Whilst easy to sharpen, the low chromium content means it will tarnish if left wet and it must therefore be wiped after use and protected by oil or wax when put away for storage.0.9C, 0.25Si, 2.0Mn, 0.35Cr, 0.1V


DNH7 is a relatively simple high carbon steel similar in composition to 1075. Differential hardening of DNH7 produces a fine working blade that holds an edge well. 0.8C 0.9Mn 0.35Si 0.045P 0.05S


A high-carbon and manganese spring steel used by Hanwei in many of their differentially hardened Japanese swords and through-hardened medieval swords. This deep hardening steel provides a consistent microstructure ensuring a long life and excellent edge holding in demanding applications.0.6-0.7C 0.85-1.15Mn


The mid-range carbon content and relatively high manganese content of 1060 makes for a tough blade steel that will withstand abusive applications, hold an edge well and sharpen easily.0.65C 0.85Mn


T10 is basically the Chinese equivalent of our 1095, but it has silicon added as an alloying element to improve the steel's strength and wear resistance (edge-holding) properties. T10 blades can be tempered to a high hardness and hold an edge well. As with 1095, rust resistance is low, and T10 blades must be carefully maintained.1.00C 0.36Mn 0.32Si


65Mn is a readily-available Chinese steel that is formulated to provide good wear resistance and hardness. The medium-high carbon content makes for a high degree of toughness and resilience, while the manganese, in addition to improving these properties, improves the hot-working characteristics of the steel, making it an excellent candidate for forged sword blades.0.62-0.7C 0.9-1.2Mn 0.17-0.37Si

Special Purpose Steels


L6 was developed for the manufacture of saw blades, with excellent resilience and impact toughness (provided by the relatively high nickel content) at high hardness levels. The Bainite phase of L6, achieved by careful heat treament, is much sought-after in sword blades.0.7-0.75C 0.5-0.7Mn 0.5Si(max) 0.7-0.9Cr 1.60Ni 0.5Mo 0.25V


5160 has achieved an excellent reputation for its toughness and resilience, particularly in larger knife blades and sword blades, where shock absorption is a requirement. Careful heat treating of a 5160 blade can produce a hard edge section and a softer core, an excellent characteristic in hacking blades.0.61C 0.94Mn 0.88Cr


52100, originally developed as a ball-bearing steel, can have an enviable combination of hardness and toughness when correctly heat treated. Mostly used by custom makers due to a tricky heat treat regimen.1.02C 0.36Mn 0.33Si 1.41Cr 0.20Ni 0.02Mo

Semi Stainless Tool Steels


Classed as a die steel, D2 has been a favorite blade material among knife users for many years. Its high chromium content almost qualifies it as "stainless" and while its stain resistance is good it does require some maintainance. The very high carbon content allows the steel to be quenched to the mid-60's HRc and drawing back to 58-60 HRC produces a tough blade with superb edge-holding properties.1.50C 0.6Mn 0.6Si 11.50Cr 0.30Ni 0.95Mo 1.1V

Stainless Steels


N690Co is made by Bohler in Austria and is their best conventional (non-powder metal) steel. N690Co is stainless and has excellent edge-holding capabilities. The high carbon content allows the steel to be tempered to 60HRc while the Cobalt inhibits cracking (chipping) at this level of hardness. The vanadium contributes to edge-holdind by producing a fine grain structure. Bohler's unique cross-rolling technology produces a homogeneous steel sheet with excellent carbide distribution.1.08C 0.40Mn 0.40Si 17.30Cr 1.10Mo 0.10V 1.5Co

ATS 34

Made by Hitachi Metals in Japan, ATS 34 has a long proven record as a high-quality blade steel, used extensively by both custom makers and manufacturers. It has excellent toughness and takes and holds a keen edge. ATS 34 is virtually identical to 154CM in its chemical composition, and is said to have been introduced as a reaction to a shortage (since rectified) of 154 CM in the alloy steel market. ATS 34 has excellent toughness and the ability to take and hold a keen edge.1.05C 0.40Mn 14.50Cr 4.00Mo


Manufactured in the U.S. by Crucible Industries, 154CM was originally developed as an aerospace steel, its high molybdenum content affording an ability to maintain strength and hardness at high temperatures. This same property proved to greatly diminish the tendency of the steel to decay in heat treatment of knife blades. Processing refinements and availability at various times have created competition between 154CM and ATS 34 but both can produce fine blades.1.05C 0.60Mn 0.25Si 14.00Cr 4.00Mo

Sandvik 14C28N

Sandvik's most recently developed product in its popular series of knife steel. The optimized composition creates a steel with a unique combination of excellent edge holding features (stability, sharpenability and sharpness), high hardness and high corrosion resistance. This new version steel has the ability to be heat treated so that the wear resistance is improved over prior steel types without affecting the microstructure. To sharpen the knife is therefore relatively easy, while edge stability in terms of chipping and edge rolling is still very good.0.62C, 0.2S, 0.6Mn, 0.025P, 0.01S, 14.0Cr, 0.11N


AUS-6 is part of the AUS family of Japanese steels, the "6" representing the 0.6% carbon content. The steel produces a tough blade with hardnesses typically in the mid-50's HRc. It will take a good edge but requires fairly frequent touch-ups in hard use.0.60C 1.00Mn 1.00Si 14.00Cr 0.49Ni 0.25V


AUS-8 is a popular blade steel and is used by both custom makers and higher-end knife manufacturers. It is a tough steel, with a hardness in the 58-59 HRc range, takes a fine edge and holds it well.0.75C 1.00Mn 1.00Si 14.00Cr 0.49Ni 0.25V


AUS-10, with its high carbon content, will produce a blade hardness in the 60-61 HRc range while maintaining very usable toughness. It will take and maintain an excellent edge. Often compared to 440C, AUS-10 has slightly less corrosion resistance in harsh environments but produces a somewhat tougher blade.1.10C 0.50Mn 1.00Si 14.00Cr 0.49Ni 0.30Mo 0.27V


420HC is a popular high-production blade steel. With low cost, easy machinability and high corrosion resistance, it produces easily affordable blades that satisfy many casual knife users. With hardnesses in the low 50's HRc it requires frequent touch ups to maintain a satisfactory edge but sharpens easily.0.50C 0.35-0.9Mn 13.50Cr 0.75Mo


The 440 series of stainless steels has been used in the manufacture of knife blades for decades but they are still the most popular steels in the commercial knife market, being readily available and producing very servicable blades. 440A has the lowest carbon content of the class but can still be heat treated to hardnesses in the mid to upper 50's HRc.0.55C 1.00Mn 1.00Si 17.00Cr


440B, with its relatively high carbon content, is used by some higher-end manufacturers. It has the ability to produce tough blades in the 59-60 HRc range and has excellent stain-resisting properties, making it a good choice for bigger blades in harsh environments.0.85C 1.00Mn 1.00Si 17.00Cr


440C was regarded by many as the top of the line stainless blade steel until the more "modern" blade steels became available, and is still very widely used in both custom and commercially produced blades. It can be heat treated to hardnesses as high as HRc61 (although 58-60 is more usual). It will take a good edge and hold it well, although fairly frequent touch-ups may be necessary under hard use.1.05C 1.00Mn 1.00Si 17.00Cr


Swedish manufacturer Sandvik has a reputation for producing high-quality steels for cutlery and edged tools. Its 12C27 stainless alloy has a fairly straightforward C/Mn/Cr composition but produces tough user blades that sharpen well and have good edge retention.0.65C 0.35Mn 13.50Cr


CPM S30V is made by the Crucible Particle Metallurgy (CPM) process by Crucible Insustries. The CPM process provides a steel with a fine grain structure and very even distribution of carbides. The relatively high Vanadium content is responsible for the formation of Vanadium Carbides, which are harder than Chromium Carbides and produce excellent edge-holding qualities. The steel is expensive to produce, which necessarily restricts its use to the high-end knife market.1.45C 0.40Mn 0.40Si 14.00Cr 2.00Mo 4.00V


VG-10 is a Japanese-made steel that has characteristics similar to N-690. The steel was originally developed for use in high-quality chef's knives but it has also become successful in knives imported from Japan for the sporting knife market. The Cobalt content allows the steel to be tempered to a high hardnesss level (HRc60+) without becoming too brittle. Many VG-10 knife blades use a thin sheet of VG-10 sandwiched between layers of other stainless steels, so exposing only an edge of VG-10.1.00C 0.50Mn 15.00Cr 1.00Ni 0.20V 1.50Co