Aluminum has a history of more than 100 years since it was discovered by Danish scientist H.C.Oersted in 1825. It has been more than 100 years since the molten salt electrolysis method (Hall-Heroult method) for industrial aluminum extraction was introduced in 1886.
Composition of Pure aluminum
Pure aluminium metal with a minimum aluminium content of 99.0% and any other element content not exceeding the thresholds specified below:
Fe+Si content is not more than 1.0%;
Other elements (including Cr, Cu, Mg, Mn, Ni, Zn. If the content of chromium and manganese does not exceed 0.05%, the content of copper is allowed to be >0.10%~≤0.20%.), each content is not more than 0.10%
What are the characteristics of pure aluminum?
Aluminum and aluminum alloys are widely used in 21century, and aluminum is widely used in various sectors of industry and agriculture, aviation, aerospace, defense industry, and even people’s daily life. Aluminum production ranks first in non-ferrous metals, second only to steel production. The reason why aluminum is widely used is that in addition to its rich reserves (about 8.2% of the mass of the earth’s crust, which is the most widely distributed metal element in the earth’s crust), and its relatively simple smelting, it is more important that aluminum has a series of excellent properties.
- ——Low density The density of pure aluminum is close to 2700KG/M³, which is about 35% of the density of iron.
——It can be strengthened Although the strength of pure aluminum is not high, it can be more than doubled by cold working. And it can be alloyed by adding magnesium, zinc, copper, manganese, silicon, lithium, scandium and other elements, and then further strengthened by heat treatment, and its strength is comparable to that of high-quality alloy steel.
——Easy processing Aluminum can be cast by any casting method. Aluminum has good plasticity and can be rolled into sheets and foils; drawn into pipes and filaments; extruded into various civilian profiles; and can be machined at the maximum speed that most machine tools can achieve, such as turning, milling, boring, and planing.
——Corrosion resistance On the surface of aluminum and its alloys, it is easy to form a dense and firm AL2O3 protective film. This protective film will only be destroyed under the intense action of halogen ions or alkali ions. Therefore, aluminum has good resistance to atmospheric (including industrial atmosphere and marine atmosphere) corrosion and water corrosion. It can resist the corrosion of most acids and organic substances. The corrosion inhibitor is used to resist the corrosion of weak alkali solution; the corrosion resistance of aluminum alloy can be improved by adopting protective measures.
——Good electrical and thermal conductivity Aluminum’s electrical and thermal conductivity is second only to silver, copper and gold. At room temperature, the equivalent volume conductivity of electrical aluminum can reach 62% IACS. If calculated by unit mass conductivity, its conductivity is twice that of copper.
——High reflectivity The reflectivity of the polished surface of aluminum to white light is more than 80%. The higher the purity, the higher the reflectivity. At the same time, aluminum has good reflective properties for infrared, ultraviolet, electromagnetic waves, and thermal radiation.
——Non-magnetic, no sparks due to impact This is very valuable for some special purposes, such as instrument materials, shielding materials for electrical equipment, flammable and explosive production equipment, etc.
——It has sound absorption, which is beneficial to interior decoration, and can also be configured as a damping alloy.
——Nuclear radiation resistance For high-energy neutrons, aluminum has the same degree of neutron absorption cross-section as other metals. For neutrons in the low-energy range, its absorption cross-section is smaller, second only to beryllium, magnesium, zirconium and other metals. The biggest advantage of aluminum’s resistance to nuclear radiation is that the induced radiation energy generated by irradiation decays very quickly.
——Beautiful appearance Aluminum and its alloys have a silvery-white luster on the surface due to their strong reflectivity. High finish and brightness can be achieved after machining. If it is anodized and colored, it can not only improve the corrosion resistance, but also obtain colorful and dazzling products. Aluminum is also an excellent substrate for the production of painted materials.
——Heat treatment, pure aluminum and anti-rust aluminum can only be subjected to annealing heat treatment, and hard aluminum, forged aluminum and anti-rust aluminum are subjected to quenching and aging as the final heat treatment method
Main grades of pure aluminum
Industrial pure aluminum grades are 1080, 1080A, 1070, 107000A(L1), 1370, 1060(L2), 1050, 1050A(L3), 1A50(LB2), 1350, 1145, 1035(L4), 1A30(L4-1) , 1100(L5-1), 1200(L-5), 1235, etc. Iron and silicon are its main impurities, and increase according to the number of grades.