The unique role of the sailing knife means that not only does it look different than other breeds, its material make up is also different. Today, when other high-end pocket knives use polished carbon steels blades with stag handles, the sailing knife prides itself on stainless steel. Earlier rigging knives are often found with carbon steel blades. In American circles this meant 1095 carbon steel. While carbon steel is more prone to rusting than stainless steel it was often favored, especially in military and many maritime circles because of its durability and toughness compared to earlier stainless steels.
As the quality of stainless steel improved, it became more readily acceptable, even ideal, for use with sea going knives due to being easier to maintain in a salt water environment. Today, most rigging knives, even those used by military personnel tend to made with stainless steel. Probably the most popular grade of Stainless used in riggers is one with a Rockwell Hardness test between 55-57 HRC; such as 420HC or an equivalent. The hardness of such a stainless is comparable to 1095 carbon steel however the high chromium content means it is compromise between edge retention, durability and corrosion resistance. Some knives, especially those that are expected to be submerged in salt water for long periods of time are made of 420 stainless. This is considered the softest of all knife steels and is considered a poor choice for most knives. However, it is valued for corrosion resistant and is therefore ideally suited for diving knives. Harder 440C is used in some commercially produced nautical knives but these tend to be more prone to corrosion and staining. Most military knives use either 420HC or 440A for the knife blade.
The U.S. Navy requires 420HC for the sheepfoot blade but allows 316 SS for the marlin spike, which is too soft for edge retention but hard enough to allow for a sharp point. It is also almost impervious to rust. This makes 316 SS a good choice for liners as it is less likely to corrode than brass. 316 SS is an austenitic (non metallic) steel. If a magnet will not stick to your marlin spike it is probably 316 stainless but not a real concern. If a magnet will not stick to your steel knife blade, your knife is garbage
Sailing knives today, are made from a variety of stainless steels. Below are some of the more common. My advice is not to get too hung up on the type of steel used. While the type of steel used is important, other factors also come into play, such as how the steel was tempered and what ype of edge was put on the blade.
13C26 Sndvik Steel: A scandinavian steel similar to 440A Stainless but considered more corrosion resistant. (.68 Carbon, .13 Chromium)
3CR13: A Chinese Stainless steel that is similar in quality to 420J2 (AUS 4) stainless steel. The following formula is a break down in the steel: Around 13% chromium and 3% carbon. It has a HRC of 52-55 making it relatively soft.
5CR13: A Chinese Stainless steel that is similar in quality to 420HC (AUS 6) stainless steel. The following formula is a break down in the steel: Around 13% chromium and 5% carbon. It has a HRC of 54-57 making it relatively soft.
7CR17MoV: A Chinese Stainless steel that is similar in quality to AUS6 stainless steel. The follwoing formula is a break down in the steel: 7CR part means it is 7% chromium and the 17MoV means .17% molybdenum and .17% Vanadium
8cr13MoV: A Chinese Stainless steel that is similar in quality to AUS8 stainless steel. The follwoing formula is a break down in the steel: 8CR part means it is 8% chromium and the 17MoV means .17% molybdenum and .17% Vanadium
12C27: A Steel with .6% carbon that originated in Scandinavia. It is roughly equivalent to 440A. It is often called Norwegian Steel.
316 Stainless Steel: Grade 316 is the standard molybdenum-bearing grade stainless steel, second in importance to 304 amongst the austenitic (non-magnetic) stainless steels. It is a surgical stainless steel. The molybdenum gives 316 better overall corrosion resistant properties than Grade 304, particularly higher resistance to pitting and crevice corrosion in chloride environments. The steel is non magnetic and makes a lousy knife blade. However, 316 is often used for other knife materials where edge retention is not required but corrosion resistance is highly valued. For this reason, it is a U.S. Military standard for marlin spikes on folding rigger knives used by the Navy and Coast Guard.
420 Stainless Steel: A low carbon content (less than .5%) stainless steel which is extremely stain resistant but soft, making it a poor choice for every day or rough use. It is, however a good choice for knives used around salt water (diving) and for decorative knives because of its rust resistant qualities. It dulls quickly and is easily nicked but is easily shaprened. Most decent nautical knife makers have moved on to better grades of steel.
420HC: A 420 stainless modified with more carbon, and normally a better heat treatment. It is said to be roughly comparable to 440A. It is an industry standard is used in knives made for U.S. military issued knives.
440 Stainless Steel: A common stainless steel used in knives that comes in three grades, A, B, and C. Normally when it advertised as 440 most people assume that it is 440A because this is considered the worst of the three grades. However, the tolerances for the amountof carbon, chromium and Molybdenum between the three steels is such, that there is some overlap and hybrid 440 steels.
440A Stainless Steel: A common stainless steel that is considered good acceptable for every day use. It has good rust resistance, and holds a reasonable edge and sharpens easily. Carbon content is around .65-.75% Chromium is 16-18% and is around Molybdenum .75%. When a knife is marketed as 440 Stainless, this is the steel they mean. It supposedly rockwell's to 56 HRC. (55-57 HRC) However, depending on who is making the knife higher Rockwell numbers are produced.
440B Stainless Steel: Stainless Steel with a minimum of 0 .9% carbon. 440Bis tougher and will handle more abuse than 440A but will rust more easily. 440B has a maximum hardness of 58HRC.
440C Stainless Steel: Stainless Steel with a minimum of 1.2% carbon This is the hardest of the 440 series It takes more abuse however it also rusts more easily than the other 440 series stainless steels. 440C can achieve a 60 HRC. At one time it was considered a stainless "Super Steel"
4116 Krupp Stainless Steel: 4116 is a fine grained, stainless steel made by ThyssenKrupp in Germany. Also called German Marine Steel, it was developed for the medical industry but is now used in food preperation. The balance of carbon and chromium content give it a high degree of corrosion resistance and also impressive physical characteristics of strength and edge holding. Edge retention is said to be on par with 440C Stainless Steel but corrosion resistance is much better. Carbon: 0.45-0.55; Si: 1.00 Mn: 1.00; P:0.040; Cr: 14.0-15.0, Mo: 0.50-0.80, V: 0.10-0.20.
ATS-34: A stainless steel considered superior to 440C Stainless Steel in most aspects but may not be as tough.
AUS-6: Japanese stainless steel, roughly comparable to, if not slightly better than 440A (AUS-6, .65% carbon)
AUS-8: Japanese stainless steel, roughly comparable to, if not slightly better than 440B (AUS-6, .75% carbon)
H-1 Super Steel: A precipitation-hardened steel containing nitrogen and designed to be rust proof. The steels composition is: Carbon-0.15%, Chromium-14.00-16.00%, Manganese-2.00%, Molybdenum-0.50-1.50%, Nickel-6.00-8.00%, Nitrogen-0.10%, Phosphorus-0.04%, Silicon-3.00-4.50%, Sulfur-0.03%. Spyderco uses the steel for dive and rescue knives that are expected to be used in high corrosion environments such as salt water. The HRC is said to be in the high 50s but Spyderco does not perform Rockwell testing on the steel. Most consider it to be on par with AUS6 or AUS 8 steel in edge retention and durability.
S30V: A registered trademarked steel of Crucible Industries LLC. It is more correctly called CPM S30V. It is a stainless steel with a compostion of Carbon 1.45%, Chromium 14.00%, Vanadium 4.00%, Molybdenum 2.00%. The Steel was developed by Dick Barber of Crucible Materials Corporation in collaboration with knifemaker Chris Reeve. CPM S30V is considered one of the Super Steel and is normally found in high-end tactical knives.
Sandvik Steel: Stainless steel of Scandinavian origin. Sandivk 13C26 is similar to 440A Stainless
VG-10: A cutlery quality steel made by Takefu Special Steel co of Japan. Its prpoerties are Carbon:1.0% Chromium:15.0% Molybdenum:1.0% Vanadium:0.2% Cobalt:1.5% The steel is used by Spyderco and Kershaw. It was orginally designed for kitchen cutlery but quickly was adopted for sport and survival cutlery. It is often referred to a "Super Steel" due to its quality.
X50CrMo: The steel used for the main cutting blades on Victroinox, Swiss Army knives. The steel for other blades on a Swiss Army Knive may prove softer or harder than this steel, depending on the purpose of the blade. For instance the Victorinox saw blades use a harder steel. X50CrMo contains: Carbon: 0.5; Chromium: 0.17; Molybdenum: 0.17. HRC: 55-57