Al - ALUMINIUM (Melting Point: 660°C)
Aluminium is a strong oxidizer (deoxidizer) and an absorber of nitrogen. When added in small amounts, it reduces the tendency of steel to age and causes the crystal structure to refine. Aluminium forms hard nitrides with nitrogen. Therefore, it is used in nitrided steels and heat-resistant ferritic steels to reduce rust formation at high temperatures. Additionally, it is used as an alloying element in iron-nickel-cobalt-aluminium magnetic steels due to its increased coercive force.
B - BORON (Melting Point: 2040°C)
Even in very low amounts (around 0.001%), boron has a significant effect. It increases the depth of hardness in quenching steels and enhances the hardness in the core of carburizing steels. Additionally, due to its high neutron absorption properties, boron is used as an alloying element in steels for nuclear energy plant construction.
C - CARBON
Carbon is the most important and influential alloying element in steel. Increasing the carbon content improves steel's hardness, strength, and wear resistance. However, it reduces the steel’s ability to be shaped at high temperatures, extend, welded, and machined. Carbon does not significantly affect steel's resistance to corrosion from moisture, acids, or hot gases.
Ca - CALCIUM (Melting Point: 850°C)
Calcium is used in the removal of sulfur and phosphorus and for deoxidation in the form of silico-calcium with silicon. It reduces the formation of hot slag in high-temperature steels.
Ce - CERIUM (Melting Point: 775°C)
Cerium, being a strong deoxidizer, has a cleaning and sulfur-removing effect in steel. It also reduces the formation of slag in high-temperature-resistant steels.
Co - COBALT (Melting Point: 1492°C)
Cobalt does not increase carbide formation, thus it does not significantly enhance hardness. However, it prevents crystal growth at high temperatures and helps to avoid the reduction of strength. For this reason, cobalt is an important alloying element in air steels, hot-working steels, and steels operating at very high temperatures. Furthermore, cobalt increases remanence, coercive force, and thermal conductivity, making it an essential alloying element in high-performance magnetic steels. Note: Cobalt is not used in steels for atomic reactors due to its ability to easily produce the radioactive isotope 60Co when exposed to neutron irradiation.
Cr - CHROMIUM (Melting Point: 1920°C)
Chromium is a strong carbide-forming element that enhances steel's strength. It also improves steel’s resistance to high temperatures, reducing slag formation. High-chromium steels are highly resistant to corrosion, wear, and rust due to chromium-carbide formation. As the chromium content increases, the ability to weld decreases. For every 1% increase in chromium, tensile strength increases by 8-10 kg/mm², and the yield point rises proportionally. However, impact resistance slightly decreases.
Cu - COPPER (Melting Point: 1084°C)
Copper increases the tensile strength and yield strength of steel, while reducing elongation and making hot working more difficult. Its most characteristic feature is its ability to significantly enhance steel’s resistance to atmospheric effects, even in small quantities.
H - HYDROGEN (Freezing Point: -262°C)
Hydrogen does not increase the strength or elastic limit of steel, but it reduces elongation and contraction rates. It causes embrittlement and promotes the formation of "flakes," which is highly detrimental to steel. Hydrogen typically enters steel during the melting process or when atomic hydrogen from acid treatment diffuses into the steel structure.
Mn - MANGANESE (Melting Point: 1244°C)
Manganese increases steel's tensile strength, yield strength, and its ability to be shaped at high temperatures and welded. Adding up to 3% manganese results in a 10 kg/mm² increase in strength for every 1% added. When manganese content is between 3% and 8%, the strength increase is lower. Beyond 8%, it can decrease strength. Manganese contents above 12-14% form an austenitic structure, and combined with high carbon, produces steels with excellent wear resistance.
Mo - MOLYBDENUM (Melting Point: 2610°C)
Molybdenum, even in small amounts, enhances hardness, tensile strength, yield strength, and resistance to high temperatures and wear. It is typically used alongside other alloying elements like chromium, nickel, and tungsten to improve hardening, toughness, and nitriding characteristics. Molybdenum is used in heat-resistant, carburizing, hot-working, ferritic, martensitic, austenitic stainless steels, and steels for high-temperature applications.
N - NITROGEN (Freezing Point: -210°C)
Nitrogen has both harmful and beneficial effects on steel. In carbon steels, nitrogen increases inter-crystal tension, brittleness, and blue staining, thus accelerating aging. However, it is beneficial in stabilizing the microstructure, particularly by increasing the hot flow limit and tensile strength. Its most important advantage is the formation of nitrides on the surface, which results in very hard surfaces, especially in nitrided steels.
Nb - NIOBIUM (Melting Point: 1950°C)
In corrosion-resistant steels, niobium is added as a stabilizer to prevent microstructure changes in combination with other elements.
Ni - NICKEL (Melting Point: 1453°C)
Nickel is one of the most important alloying elements added to steel. It increases steel's strength, deepens hardness during quenching, improves impact resistance, and enhances corrosion and high-temperature resistance. For this reason, it is a critical alloying element in machine structural steels, stainless steels resistant to rust and acid, and steels operating at high temperatures.
O - OXYGEN (Freezing Point: -218.7°C)
Oxygen is a harmful element for steel in every way. Therefore, one of the main goals during production is to remove oxygen from the steel.
P - PHOSPHORUS (Melting Point: 44°C)
Due to its presence in raw materials, phosphorus is almost always introduced into the steel structure during production and is generally harmful, requiring removal. However, in automatic steels, phosphorus is kept at higher levels than normal, as it increases brittleness in machining and improves fluidity in castings.
Pb - LEAD (Melting Point: 327°C)
Lead is added in small amounts (0.2-0.5%) only to automatic steels and is distributed very finely in the form of suspension. As a result, it helps to make chips brittle and achieves a clean surface. It does not significantly affect the mechanical properties of the steel.
S - SULFUR (Melting Point: 118°C)
Sulfur, due to its presence in raw materials, always enters the steel structure during production, making the steel brittle and red-hot brittle, and is generally considered a harmful element that needs to be removed. However, in automatic steels, sulfur content is increased (up to 0.4%) to improve the brittleness of chips.
Se - SELENIUM (Melting Point: 217°C)
Selenium's effect is similar to that of sulfur, but it is stronger. Therefore, it is used in some automatic steels.
Si - SILICON (Melting Point: 1410°C)
Silicon is a metalloid that is always present in trace amounts in steel and is most commonly used as a deoxidizer (deoxidant) in steel production. It is also an important alloying element in many steels (when present in quantities greater than 0.5%). As an alloying element, silicon increases the hardness, yield strength, and tensile strength of steel (increasing strength by 10 kg/mm² per 1% Si), reduces slag formation at high temperatures, enhances magnetic properties, and improves resistance to acids at both high and low temperatures when present in quantities over 12%. Silicon is used as an alloying element in spring steels, many structural steels, heat-resistant steels, transformer sheet production, and acid-resistant castings and steels.
Ti - TITANIUM (Melting Point: 1812°C)
Titanium is a very hard metal that forms carbides and is primarily used as a stabilizing element against inter-crystal corrosion in corrosion-resistant steels. Additionally, when added in small amounts during steel production, it acts as a deoxidizer.
V - VANADIUM (Melting Point: 1730°C)
Vanadium is an alloying element that shows its effects even when used in small quantities. It increases steel’s resistance to high temperatures, facilitates carbide formation, and improves tensile strength and yield strength. Vanadium is particularly important, especially when combined with chromium, in various machine structural steels, high-temperature-resistant steels, and, together with tungsten, in air steels and hot-working steels.
W - TUNGSTEN (Melting Point: 3380°C)
Tungsten is an essential alloying element in steels, ensuring increased hardness and tensile strength, while maintaining these properties at high temperatures. It is used in the production of air steels, hot-working steels, and similar steels. Due to its carbide-forming properties, tungsten increases the tensile strength and yield strength of steel (increasing strength by 4 kg/mm² for each 1% tungsten).
Zr - ZIRCONIUM (Melting Point: 1860°C)
Zirconium acts as a deoxidizer in steel production, leaving minimal deoxidation residues. It also helps remove sulfur and nitrogen and is used as an alloying element in certain types of heat-resistant steels. Additionally, zirconium has carbide-forming properties.