Non ferrous metal are specified for structural applications requiring reduced weight, higher strength, nonmagnetic properties, higher melting points, or resistance to chemical and atmospheric corrosion. They are also specified for electrical and electronic applications.
The non-ferrous metal group includes:
Pure aluminum is a silvery-white metal with many desirable characteristics. Light and nontoxic (as the metal), nonmagnetic and nonsparking. it is easily formed, machined, and cast. Although Pure aluminum is soft and lacks strength, alloys with small amounts of copper, magnesium, silicon, manganese, and other elements have very useful properties. It is an abundant element in the earth’s crust, but is not found free in nature. The Bayer process is used to refine aluminum from bauxite, an aluminum ore. Aluminum has no limit to the number of times it can be recycled in its lifetime. Because of aluminum’s many desirable properties, it is an extremely convenient and widely used metal.
Some common uses of aluminum are in the Building & Construction Industry (door and window frames, wall cladding, roofing, awnings), Manufacture of Electrical Products ( high tension power lines, wires, cables, busbars, television & radio components as well as refrigerator and air conditioning components), Packaging & Containers (beverage cans, bottle tops, foil wraps, foil semi rigid containers), Cooking Utensils (kettles, saucepans), Aeronautical, Aviation & Automotive Industries (propellors, airplane & vehicle bldy sheet, gearboxes, motor parts), Leisure Goods (tennis racquets, softball bats, indoor/outdoor furniture)
Of the light metals, beryllium has one of the highest melting points . The elasticity properties of beryllium is approximately 1/3 times greater than that of steel. A nonmagnetic metal that resists attack by concentrated nitric acid, it has excellent thermal conductivity. Highly permeable to X-rays, the neutrons are liberated when it is hit by alpha particles, as from radium or polonium (about 30 neutrons/million alpha particles). Beryllium resists oxidation when exposed to air at standard temperature and pressures (although its ability to scratch glass is probably due to the formation of a thin layer of the oxide). Beryllium is a very light weight metal with high elasticity properties (five times that of ultrahigh-strength steels), high specific heat, and high specific strength (strength to weight ratio).
Beryllium is used as an alloying agent in the production of beryllium-copper because of its ability to absorb large amounts of heat. Beryllium-copper alloys are used in a wide variety of applications because of their electrical and thermal conductivity, high strength and hardness, nonmagnetic properties, along with good corrosion and fatigue resistance. Applications include the making of spot-welding electrodes, springs, non-sparking tools and electrical contacts.
Beryllium-copper alloys are also used in the defense and aerospace industries as light-weight structural material in high-speed aircraft, missiles, space vehicles and communication satellites due to their stiffness, light weight, and dimensional stability over a wide temperature range. Thin sheets of beryllium foil are used with X-ray detection diagnostics to filter out visible light and allow only X-rays to be detected. In the field of X-ray lithography, beryllium is used for the reproduction of microscopic integrated circuits. Because the beryllium has a low thermal neutron absorption cross section, the nuclear power industry uses this metal in nuclear reactors as a neutron reflector and moderator. It is also used in nuclear weapons for similar reasons. For example, the critical mass of a plutonium sphere is significantly reduced if the plutonium is surrounded by a beryllium shell. However, this metal is brittle, chemically reactive, expensive to refine and form, and its impact strength is low compared to values for most other metals.
Copper has good thermal and electrical conductivity, corrosion resistance, ease of forming, ease of joining, and color but, copper and its alloys have relatively low strength-to-weight ratios and low strengths at elevated temperatures. There are some copper alloys that are also susceptible to stress-corrosion cracking unless they are stress relieved. Besides silver, copper is the next best electrical conductor. It is a yellowish red metal that polishes to a bright metallic luster and is tough, ductile and malleable. Having disagreeable taste and a peculiar smell, copper is resistant to corrosion in most atmospheres including marine and industrial environments. Oxidizing acids, halogens, sulphides and ammonia based solutions.cause it to corrode
Copper and its alloys (brasses and bronzes) are available in rod, plate, strip, sheet, tube shapes, forgings, wire, and castings.
Lead is the most resistant of all the common metals to X-rays and gamma radiation, and it also resists attack by many corrosive chemicals, most types of soil, and marine and industrial environments. The main reasons for using lead often include its low melting temperature, ease of casting and forming, high density, good sound and vibration absorption, and ease of salvaging from scrap. Sheet lead, lead-loaded vinyls, lead composites, and lead-containing laminates are used to reduce machinery noise. Natural lubricity and wear resistance of lead make this metal the most suitable of the alloys, for heavy-duty bearing applications such as railroad-car journal bearings and piston-engine crank bearings.
Magnesium is the lightest structural metal available as it has a high strength-to-weight ratio. With its low elasticity properties combined with moderate strength, magnesium alloys can absorb energy elastically, providing excellent dent resistance and high damping capacity. It is a metal that has good fatigue resistance and performs particularly well in applications involving a large number of cycles at relatively low stress. Itis sensitive to stress concentration so notches, sharp corners, and abrupt section changes should be avoided. These alloys are the easiest of the structural metals to machine and they can be shaped and fabricated by most metalworking processes, including welding.
Applications that require specific corrosion resistance or elevated temperature strength are well suited to nickel. Nickel alloys are among the toughest structural materials known. When compared to steel, nickel alloys have ultrahigh strength, high proportional limits, and high elasticity properties. Commercially pure nickel has good electrical, magnetic, and magnetostrictive properties.
- Gold is an extremely inert, soft, ductile metal. Chiefly used for linings or electrodeposits it is often alloyed with other metals such as copper or nickel to increase strength or hardness.
- Silver is a very malleable, ductile, and corrosion resistant metal. It has the highest thermal and electrical conductivity of all metals and is the least expensive of all the precious metals. Alloyed with copper, and sometimes with zinc, silver is also used in high-melting temperature solders.
- Platinum is an extremely malleable, ductile, and corrosion resistant silver-white metal. It softens and is easily worked, when heated to redness. Nearly nonoxidizable, it is soluble only in liquids that generate free chlorine such as aqua regia. Because platinum is inert and stable, even at high temperatures, it is used for high-temperature handling of high-purity chemicals and laboratory materials. Some other applications include electrical contacts, resistance wire, thermocouples, and standard weights.
Characterized by their extremely high melting points, which range well above those of iron, cobalt, and nickel are refractory metals. Used in demanding applications requiring high-temperature strength and corrosion resistance, the most extensively used of these metals are tungsten, tantalum, molybdenum, and columbium (niobium).
Tin is characterized by a low-melting point (450°F), fluidity when molten, readiness to form alloys with other metals, relative softness, and good formability. This metal is nontoxic, solderable, and has a high boiling point. Its temperature range between melting and boiling points exceeds that for nearly all other metals (which facilitates casting). The prrincipal uses for tin are as a constituent of solder and as a coating for steel (tinplate, or terneplate). Sometimes it is also used in bronze, pewter, and bearing alloys.
Titanium alloys come in three structural types::
- Alpha Alloys are non-heat treatable and are generally very weld- able. They have low to medium strength, good notch toughness, reasonably good ductility and possess excellent mechanical properties at cryogenic temperatures. More highly alloyed alpha and near-alpha alloys offer optimum high temperature creep strength and oxidation resistance as well.
- Alpha-Beta Alloys are heat treatable and most of them re weldable. Their strength levels are medium to high. Their hot-forming qualities are good, but the high temperature creep strength is not as good as in most alpha alloys.
- Beta or near-beta alloys are readily heat treatable, generally weldable, capable of high strengths and good creep resistance to intermediate temperatures. Excellent formability can be expected of the beta alloys in the solution treated condition. Beta-type alloys have good combinations of properties in sheet, heavy sections, fasteners and spring applications.
A silvery blue-grey metal with a relatively low melting point (419.5°C) and boiling point (907°C) is zinc. Its strength and hardness are greater than that of tin or lead when unalloyed, but appreciably less than that of aluminium or copper. The pure metal cannot be used in stressed applications due to low creep-resistance. Most uses of zinc are after alloying with small amounts of other metals, or as a protective coating for steel.
The most useful characteristics of zinc is its resistance to atmospheric corrosion, and just over half of its use is for the protection of steelwork. In addition to its metal and alloy forms, zinc also extends the life of other materials such as steel (by hot dipping or electrogalvanizing), rubber and plastics (as an aging inhibitor), and wood (in paints). It is also used to make brass, bronze, and die-casting alloys in plate, strip, and coil; foundry alloys; superplastic zinc; and activators and stabilizers for plastics.