What makes a blade? Ingredients of Steel alloys and their properties.
This is not so much a post about blade shape, size or a blades uses but a look into the composition of a blade and the elements which give it its properties. Alloys are a mixture of 2 or more metals. Copper is a common metal, and one of the first that was used by ancient man. When Copper is mixed with Zinc becomes an alloy known as Brass. Brass retains the properties of Copper, but is significantly stronger than pure Copper. This is just one example of how two metals can be mixed to form an alloy of improved qualities. Modern blades are mainly derived from a Steel alloy. Steel is made mostly of Iron mixed with Carbon. Depending on what other elements are added to the Steel, a blade can take on many different properties such as improved conductivity, flexibility, strength, corrosion resistance and magnetic resistance. Here is a list of such additives, and their effects on Steel alloys; Carbon
Carbon is an incredibly common mineral. Humans, and all living creatures on Earth are composed of Carbon. Carbon is also interesting in regards to its ability to bond in many different organic and inorganic forms. Carbon is the primary element in graphite used in pencils, non liquid lubricants due to its low friction properties and also bonds to form Diamonds, one of the hardest naturally occurring minerals. When added to a Steel alloy Carbon produces the following qualities;
Increases hardness and improves resistance to wear and abrasion.
Reduces ductility and provides hardenability.
Increases edge retention and raises tensile strength.
Chromium
Another fairly common element, Chromium was discovered to be incredibly important to the Steel industry. When added to regular Steel Chromium gives significant stain resisting abilities and a resistance to corrosion due to the fact that it forms a protective oxide layer. If it is not feasible to create an alloy directly involving Chromium it is possible to apply a layer of chromium to the external surface of a steel product. currently about 80% of all Chromium mined is used to produce stainless or corrosive resistant Steel. Although stainless steel is an excellent alloy for knives, it can become brittle when used in blades over 35 cms in length, thus it is discouraged for use in swords. When added to a Steel alloy Chromium produces the following qualities;
More than 11% makes it "stainless", by causing an oxide coating to form.
Increases hardness, tensile strength, and toughness and provides resistance to wear and corrosion.
Cobalt
Cobalt sees use in several applications. It is used as a radioactive tracer in the medical industry and to produce high intensity gamma rays. Cobalt also sees use as an additive to steel to further its positive attributes as an alloy. To date the Democratic Republic of Congo is the biggest known miner of the Cobalt mineral. When added to a Steel alloy Cobalt produces the following qualities;
Increases strength and hardness, and permits quenching in higher temperatures.
Copper
Copper is a fairly common mineral but due to high demand it can be quite expensive. Due to recent price rises it has not been uncommon for criminals to steal large amounts of Copper. Copper is an excellent conductor of electricity it is used in great quantities in power lines, fuse boxes and switchboards. Remote power stations and high voltage power lines are often targeted. Once poles holding the lines up are cut and the wire disconnected the Copper is extracted and sold as scrap. A few years ago a truck was caught with several million dollars worth of stolen cargo consisting of Copper wiring that was harvested in this manner. Good quality Copper can fetch over $8.00 a kg as scrap. When added to a Steel alloy Copper produces the following qualities;
Significant increase in corrosion resistance.
Manganese
Not to be confused with Magnesium, Manganese is a dull grey to silver metal that is essential in trace amounts to all known living organisms. In high quantities Manganese is highly toxic and is known to cause debilitating neurological damage that is sometimes irreversible. Manganese is a very important mineral for producing high grade Steel alloys, with around 90% being used for the purpose of steel manufacturing. Manganese is also used in some Aluminium alloys. When added to a Steel alloy Manganese produces the following qualities;
Deoxidizes and degasifies to remove oxygen from molten metal.
In larger quantities, increases hardness and brittleness.
Increases hardenability, wear resistance, and tensile strength.
Molybdenum
This silvery metal is special in regards to its ability to withstand incredible heat and its ability to form stable carbides in an alloy. It has the 6th highest melting point of all known metals and due to its impressive properties about 80% of all Molybdenum produced is used in the manufacture of Steel alloys. When added to a Steel alloy Molybdenum produces the following qualities;
Increases strength, hardness, hardenability, and toughness.
Improves machinability and resistance to corrosion.
Nickel
Nickel is a funny little mineral, and historically has been used as an anti-corrosive in metal alloys due to its slow rate of oxidization. Nickle has also been used to coat base metals as it has a nice bright silver shine when polished. One of the most bizarre facts about Nickle is that in many Australian schools students are prohibited from handling nickle samples in the lab due to the fact that it is carcinogenic (cancer causing). This makes absolutely no sense as all Australian silver coins are made from Nickle.
When added to a Steel alloy Nickle produces the following qualities;
Usually improve corrosion resistance and reduces hardness.
Adds toughness.
Phosphorus
Phosphorus is a highly reactive non-metal element. Due to its ability to react with air it is never present in its pure form in the natural environment. Phosphorus is primarily used in fertilizers to return phosphorus to the soil that are extracted by plants. Phosphorus is essential to all mammalian life as it plays an important role in energy production in the body. When added to a Steel alloy Phosphorus produces the following qualities;
Improves strength, machinability, and hardness.
Creates brittleness in high concentrations.
Silicon
Silicon is a non metal that has several metal properties. It sees a lot of use in the computer industry in the production of silicone computer chips. Silicone is also an important ingredient in the production of high strength abrasive and ceramics. To date it is the second most abundant element on the planet and the 8th most abundant in the Universe by mass. When added to a Steel alloy Silicon produces the following qualities;
Deoxidizes and degasifies to remove oxygen from molten metal.
Increases strength.
Sulfur
Sulfur is a common mineral that can often be found in pure form. Its primary use is in fertilizer, but it is used in many other applications such as fungicides, insecticides and match heads. Sulfur gas has a distinct rotten eggs smell and combined with its yellow, powdery appearance is easy to recognize. Although Sulfur is essential for human biological functions too much can be highly toxic. Sulfur is also an important ingredient of gun powder. When added to a Steel alloy Sulfur produces the following qualities;
Usually considered a contaminant.
Improves machinability when added in minute quantities.
Tungsten
Tungsten is very special in regards to its uses and properties. Tungsten has the highest melting point of all Earth metals and is quite rare. It sees use in applications such as light bulbs, x-ray tubes and as a catalyst in industrial applications. Due to it incredible strength tungsten is used in military applications as a penetrating projectile. When added to a Steel alloy Tungsten produces the following qualities;
Retains hardness at elevated temperature.
Adds strength, toughness, and improves hardenability.
Vanadium
Vanadium is amazing stuff. I have two large pig knives made of Vanadium and I can vouch for their strength. Vanadium is a rare metal element that is often mined as a bi-product of uranium ore mining. Due to its properties Vanadium is often used in the production of high speed tool steels, and in the production of sulfuric acid. When added to a Steel alloy Sulfur produces the following qualities;
Carbide inclusions are very hard.
Expensive.
Chips frequently.
Improves corrosion resistance by contributing to the oxide coating.
Increases strength, wear resistance, and increases toughness.
Writers note: This concludes the list of common Steel alloy additives. I have written this list in the hopes that next time a fellow adventurer is browsing for a new blade they may have a more complete understanding of the blade they are buying and its properties in regards to ability to withstand abuse and its ability to endure moisture. The pictures are not my own, and full credit goes to the original photographer. Information is as accurate as possible, if there is a mistake please don't hesitate to let me know.