First, carbon (C): carbon content in steel increases, the yield point and the tensile strength increased, but reduced ductility and impact resistance, when the carbon content exceeds 0.23%, weldability deteriorates, and therefore for welding Low alloy structural steel, carbon content of not more than 0.20%. But it also reduces the amount of high-carbon steel resistant to atmospheric corrosion, high carbon steel in the open-air yard would easily corroded; in addition, carbon can be increased sensitivity to cold brittleness and aging steel.
Second, silicon (Si): plus silicon as a reducing agent in the steel making process and deoxidizer, it killed steel containing 0.15-0.30% silicon. If the steel is more than 0.50-0.60% silicon, silicon even if alloying elements. Silicon can significantly improve the elastic limit of the steel, the yield point and tensile strength, it is widely used as a spring steel. Added 1.0-1.2% silicon structure in quenched and tempered steel, strength can be increased by 15-20%. Silicon and molybdenum, tungsten, chromium, combined with improving corrosion resistance and antioxidant effects, can produce heat-resistant steel. Silicon 1-4% of low-carbon steel, with a high permeability, do silicon steel for electrical industry. Increase the amount of silicon will reduce weldability.
Third, manganese (Mn): in steelmaking process, manganese is a good deoxidizer and desulfurizer, generally 0.30-0.50% manganese steel. In carbon steel added 0.70% or even "manganese", than the average amount of steel steel not only has enough toughness, and has high strength and hardness, improved hardenability of steel to improve the hot workability of steel, 40% higher than the A3 as 16Mn steel yield points. 11-14% manganese steels have high wear resistance, for the excavator bucket, ball mill liners and the like. Manganese content increased, reduced corrosion resistance of the steel, reduce welding performance.
Fourth, phosphorus (P): In general, phosphorus is harmful elements in steel, increased cold brittleness of steel, welding performance deterioration, reduced ductility, so cold bending performance deterioration. Therefore typically require phosphorus content in steel is less than 0.045%, high-quality steel requires lower.
Fifth, sulfur (S): sulfur is usually harmful elements. Hot brittleness of the steel produced, reducing the ductility and toughness of the steel, causing cracks in the forging and rolling. Sulfur is also detrimental to the welding performance and reduce corrosion resistance. So often it requires a sulfur content of less than 0.055%, 0.040% or less than the requirements of high-quality steel. Join 0.08-0.20% sulfur in the steel can be improved machinability, commonly referred to cutting steel.
Sixth, chromium (Cr): the structural steel and tool steel, chromium can significantly improve the strength, hardness and wear resistance, but at the same time reducing the ductility and toughness. Chrome steel can improve the oxidation resistance and corrosion resistance, so it is stainless steel, heat-resistant steel alloying elements important.
Seven of nickel (Ni): Ni can improve the strength of steel, while maintaining good ductility and toughness. Nickel acid have a higher corrosion resistance, high temperature and heat capacity of rust. But because the nickel is relatively scarce resources, it should be possible to use other alternative alloying elements nickel-chromium steel.
Eight, molybdenum (Mo): Molybdenum makes grain refinement of steel to improve hardenability and thermal performance, maintain sufficient strength at high temperatures and creep resistance (long subjected to stress at high temperature, deformation, said creep). Adding molybdenum steel, can improve the mechanical properties. It can also suppress the brittle steel due to the fire caused. In tool steel can improve red sex.
Nine, titanium (Ti): Ti is a strong deoxidizer in steel. It enables the internal organization of the steel dense grain refinement force; reduce aging sensitivity and cold brittleness. Improve welding performance. Adding the appropriate titanium in nickel-chromium 18 9 austenitic stainless steel, intergranular corrosion can be avoided.
Ten, vanadium (V): Vanadium is an excellent steel deoxidizer. Steel added 0.5% vanadium can be refined grains organization, to improve the strength and toughness. Vanadium carbide and carbon formed under high temperature and pressure can increase resistance to hydrogen corrosion.
XI, tungsten (W): tungsten high melting point, specific gravity, is born expensive alloying elements. Tungsten carbide with carbon has high hardness and wear resistance. Plus tungsten in tool steel, can significantly improve the red hardness and heat resistance, for cutting tools and forging mold.
Twelve, niobium (Nb): Nb can refine the grain and reduce heat sensitivity and temper brittleness of steel, increase strength, but ductility and toughness decrease. Niobium in an ordinary low-alloy steel, it can improve the anti-hydrogen, nitrogen, ammonia corrosion resistance to atmospheric corrosion and high temperature under. Niobium can improve welding performance. Increase in austenitic stainless steels, niobium prevents intergranular corrosion phenomenon between.
XIII, cobalt (Co): Cobalt is a rare precious metal, used for special steels and alloys, such as steel and heat resistant material.
Fourth, copper (Cu): Wuhan Iron and Steel Daye ore by the steel refining, often contain copper. Copper can improve the strength and toughness, especially atmospheric corrosion. The disadvantage is that during thermal processing prone to thermal embrittlement, significantly reduces the copper content exceeds 0.5% plasticity. When the copper content is less than 0.50% no effect on weldability.
Fifth, aluminum (Al): Aluminum is commonly used steel deoxidizer. Steel adding a small amount of aluminum, refined grains can improve the impact toughness, such as deep-drawing steel sheet of 08Al. Aluminum also has antioxidant and anti-corrosion, aluminum and chromium, silicon combination, can significantly improve the ability of high-temperature steels and high temperature performance can not afford to skin corrosion. The disadvantage of aluminum is affecting the hot workability of steel, welding performance and cutting performance.
Sixteen, boron (B): Boron steel can be improved by adding small amounts of dense and hot-rolled steel performance, increase strength.
XVII nitrogen (N): N can improve the strength of steel, low-temperature toughness and weldability, increased sensitivity to aging.
Eighth, RE (Xt): rare earth element refers to the Periodic Table of atomic number 57-71 15 lanthanides. These elements are metal, but their oxides are like "earth", so called rare earths is customary. Steel adding rare earth, can change the composition of inclusions in steel, morphology, distribution, and nature, thereby improving the various properties of steel, such as toughness, weldability, cold workability. Plowshare adding rare earth in steel can improve the wear resistance.
