Non-ferrous metals are those metals that do not contain iron as a principle ingredient (they can contain a small percentage.)
These types of metals are used in a wide variety of industrial applications.
Widely used metals are:
- Copper (CU): used for high electrical and thermal conductivity
- Aluminum (Al), beryllium (Be), titanium: used in structural applications
- Magnesium (Mg), lithium, potassium, sodium: engineering applications
- Tin (Sn), cadmium (Cd), zinc (Zn): used for coatings, electrical use, for surfaces of bearings
- Cobalt (Co), manganese (Mn): alloys in steel
- Nickel (Ni), lead (Pb): widespread use
- Gold, silver, platinum: electrical applications, jewelry
- Columbium (Cb), titanium (Ti), zirconium (Zr), vanadium (V), tungsten (W): refractory metals that have melting points above 3600 degrees F (2000 degrees Celsius). Used for heat shield, tool coatings.
- Plutonium, thorium, uranium: nuclear fuels are non ferrous metals
- Molybdenum (Mo)
- Bismuth (Bi)
- Tantalum (Ta)
- Gallium (Ga)
- Hafnium (Hf)
- Indium (In)
- Niobium (Nb)
- Rhenium (Re)
- Antimony (Sb)
- Manganese (Mn)
- Germanium (Ge)
- Thallium (Ti)
Metals are chosen for different applications based on their properties.
History Non-ferrous Metals
The production of non-ferrous metals pre dates the Middle Ages. Records show the mining of lead and copper for centuries, while tin was extracted during the Roman era.
The industrial revolution led to increased use of nonferrous metals. With the growth in the industry, interest increased in production of each metal as well as re-smelting scrap metals.
Basic Forms of Non-Ferrous Metals
- Bars and Rods: manufactured by rolling extrusion, forging or drawing the metal
- Plates, Sheets, Strips and Foil (backed foil, coated foil): flat-surfaced products
- Profiles: rolled, extruded, drawn, forged or formed products
- Tubes, pipes: hollow products
- Wire (strands, rope and cable, ribbon, insulated wire, welding wire)
Aluminum is a lightweight, soft, low strength metal which can easily be cast, forged, machined, formed, and welded. It is suitable only in low temperature applications, except when alloyed with specific elements.
Commercial aluminum alloys are classified into two groups, wrought alloys and cast alloys. The wrought alloy group includes those alloys which are designed for mill products whose final physical forms are obtained by working the metal mechanically. The casting alloy group includes those alloys whose final shapes are obtained by allowing the molten metal to solidify in a mold.
Alloys aluminum can be strengthened so that it is stronger than structural steel.
Aluminum is used as a deoxidizer and alloying agent in the manufacture of steel. Castings, pistons, torque converter pump housings, aircraft structures, kitchen utensils, railways cars, and transmission lines are made of aluminum.
Aluminum can be cast, forged, machined, formed, and welded.
Direct metal contact of aluminum with copper and copper alloys should be avoided. Aluminum should be used in low-temperature applications.
Pure aluminum has a Brinell hardness number of 17 to 27; tensile strength of 6000 to 16,000 psi (41,370 to 110,320 kPa); specific gravity of 2.7; and a melting point of 1220°F (660°C). Aluminum alloys have a Brinell hardness number of 100 to 130, and tensile strength of 30,000 to 75,000 psi (206,850 to 517,125 kPa). Generally, aluminum and aluminum alloys have excellent heat conductivity; high electrical conductivity (60 percent that of copper, volume for volume; high strength/weight ratio at room temperature; and unfairly corrosion resistant.
Aluminum is light gray to silver in color, very bright when polished, dull when oxidized, and light in weight. Rolled and sheet aluminum materials are usually pure metal. Castings are alloys of aluminum with other metals, usually zinc, copper, silicon, and sometimes iron and magnesium. Wrought aluminum alloys may contain chromium, silicon, magnesium, or manganese. Aluminum strongly resembles magnesium in appearance. Aluminum is distinguished from magnesium by the application of a drop of silver nitrate solution on each surface. The silver nitrate will not react with the aluminum, but leaves a black deposit of silver on the magnesium.
A fracture in rolled aluminum sections shows a smooth, bright structure. A fracture in an aluminum casting shins a bright crystalline structure.
No sparks are given off from aluminum.
Aluminum does not turn red before melting. It holds its shape until almost molten, then collapses (hot shorts) suddenly. A heavy film of white oxide forms instantly on the molten surface.
Chromium is an alloying agent used in steel, cast iron, and nonferrous alloys of nickel, copper, aluminum, and cobalt. It is hard, brittle, corrosion resistant, can be welded, machined, forged, and is widely used in electroplating. Chromium is not resistant to hydrochloric acid and cannot be used in its pure state because of its difficulty to work.
Chromium is one of the most widely used alloys. It is used as an alloying agent in steel and cast iron (0.25 to 0.35 percent) and in nonferrous alloys of nickel, copper, aluminum, and cobalt. It is also used in electroplating for appearance and wear, in powder metallurgy, and to make mirrors and stainless steel.
Chromium alloys can be welded, machined, and forged. Chromium is never used in its pure state.
Chromium is not resistant to hydrochloric acid, and cannot be used in the pure state because of its brittleness and difficulty to work.
Chromium has a specific gravity of 7.19; a melting point of 3300°F (1816°C); Brinell hardness number of 110 to 170; is resistant to acids other than hydrochloric; and is wear, heat, and corrosion resistant.
Cobalt is a hard, white metal similar to nickel in appearance, but has a slightly bluish cast.
Cobalt is mainly used as an alloying element in permanent and soft magnetic materials, high-speed tool bits and cutters, high-temperature, creep-resisting alloys, and cemented carbide tools, bits, and cutters. It is also used in making insoluble paint pigments and blue ceramic glazes. In the metallic form, cobalt does not have many uses. However, when combined with other elements, it is used for hard facing materials.
Cobalt can be welded, machined (limited), and cold-drawn.
Cobalt must be machined with cemented carbide cutters. Welding high carbon cobalt steel often causes cracking.
Pure cobalt has a tensile strength of 34,000 psi (234,430 kPa); Brinell hardness number of 125; specific gravity of 8.9; and a melting point of 2720°F (1493°C). Cobalt alloy (Stellite 21) has a tensile strength of 101,000 psi (696,395 kPa) and is heat and corrosion resistant.
Copper is a reddish metal, is very ductile and malleable, and has high electrical and heat conductivity. It is used as a major element in hundreds of alloys. Commercially pure copper is not suitable for welding. Though it is very soft, it is very difficult to machine due to its high ductility.
- Beryllium copper contains from 1.50 to 2.75 percent beryllium. It is ductile when soft, but loses ductility and gains tensile strength when hardened.
- Nickel copper contains either 10, 20, or 30 percent nickel. Nickel alloys have moderately high to high tensile strength, which increases with the nickel content. They are moderately hard, quite tough, and ductile. They are very resistant to the erosive and corrosive effects of high velocity sea water, stress corrosion, and corrosion fatigue.Nickel is added to copper zinc alloys (brasses) to lighten their color; the resultant alloys are called nickel silver. These alloys are of two general types, one type containing 65 percent or more copper and nickel combined, the other containing 55 to 60 percent copper and nickel combined. The first type can be cold worked by such operations as deep drawing, stamping, and spinning. The second type is much harder end is not processed by any of the cold working methods. Gas welding is the preferred process for joining copper and copper alloys.
The principal use of commercially pure copper is in the electrical industry where it is made into wire or other such conductors. It is also used in the manufacture of nonferrous alloys such as brass, bronze, and Monel metal. Typical copper products are sheet roofing, cartridge cases, bushings, wire, bearings, and statues.
Copper can be forged, cast, and cold worked. It can also be welded, but its machinability is only fair. Copper alloys can be welded.
Electrolytic tough pitch copper cannot be welded satisfactorily. Pure copper is not suitable for welding and is difficult to machine due to its ductility.
Pure copper is nonmagnetic; has a Brinell hardness number of 60 to 110; a tensile strength of 32,000 to 60,000 psi (220,640 to 413,700 kPa); specific gravity of 8.9; melting point of 1980°F (1082°C); and is corrosion resistant. Copper alloys have a tensile strength of 50,000 to 90,000 psi (344,750 to 620,550 kPa) and a Brinell hardness number of 100 to 185.
Copper is red in color when polished, and oxidizes to various shades of green.
Copper presents a smooth surface when fractured, which is free from crystalline appearance.
Copper gives off no sparks.
Because copper conducts heat rapidly, a larger flame is required to produce fusion of copper than is needed for the same size piece of steel. Copper melts suddenly and solidifies instantly. Copper alloy, containing small amounts of other metals, melts more easily and solidifies more slowly than pure copper.
Brass and Bronze
Brass, an alloy of copper and zinc (60 to 68 percent copper and 32 to 40 percent zinc), has a low melting point and high heat conductivity. There are several types of brass, such as
All differ in copper and zinc content; may be alloyed with other elements such as lead, tin, manganese, or iron; have good machinability; and can be welded. Bronze is an alloy of copper and tin and may contain lead, zinc, nickel, manganese, or phosphorus. It has high strength, is rust or corrosion resistant, has good machinability, and can be welded.Brass is almost identical characteristics to copper.
Bronze is a copper alloy that is similar to brass in application, but is harder and more expensive.
The color of polished brass and bronze varies with the composition from red, almost like copper, to yellow brass. They oxidize to various shades of green, brown, or yellow.
The surface of fractured brass or bronze ranges from smooth to crystalline, depending upon composition and method of preparation; i. e., cast, rolled, or forged.
Brass and bronze give off no sparks.
Brass contains zinc, which gives off white fumes when it is melted. Bronze contains tin. Even a slight amount of tin makes the alloy flow very freely, like water. Due to the small amount of zinc or tin that is usually present, bronze may fume slightly, but never as much as brass.
Aluminum Bronze Tests
When polished, aluminum bronze appears a darker yellow than brass.
Aluminum bronze presents a smooth surface when fractured.
Aluminum bronze gives off no sparks.
Welding aluminum bronze is very difficult. The surface is quickly covered with a heavy scum that tends to mix with the metal and is difficult to remove.
Lead is a heavy, soft, malleable metal with low melting point, low tensile strength, and low creep strength.
It is resistant to corrosion from ordering atmosphere, moisture, and water, and is effective against many acids. Lead is well suited for cold working and casting.
The low melting point of lead makes the correct welding rod selection very important.
Lead dust and fumes are poisonous. Exercise extreme care when welding lead, and use personal protective equipment.
Lead is used mainly in the manufacture of electrical equipment such as lead-coated power and telephone cables, and storage batteries. It is also used in building construction in both pipe and sheet form, and in solder. Zinc alloys are used in the manufacture of lead weights, bearings, gaskets, seals, bullets, and shot. Many types of chemical compounds are produced from lead; among these are lead carbonate (paint pigment) and tetraethyl lead (antiknock gasoline). Lead is also used for X-ray protection (radiation shields). Lead has more fields of application than any other metal.
Lead can be cast, cold worked, welded, and machined. It is corrosion, atmosphere, moisture, and water resistant, and is resistant to many acids.
Lead has low strength with heavy weight. Lead dust and fumes are very poisonous.
Pure lead has tensile strength of 2500 to 3000 psi (17,237.5 to 20,685 kPa); specific gravity of 11.3; and a melting point of 620°F (327°C).
Alloy lead B32-467 has tensile strength of 5800 psi (39,991 kPa). Generally, lead has low electrical conductivity; is self-lubricating; is malleable; and is corrosion resistant.
Magnesium is an extremely light metal, is white in color, has a low melting point, excellent machinability, and is weldable. Welding by either the arc or gas process requires the use of a gaseous shield. Magnesium is moderately resistant to atmospheric exposure, many chemicals such as alkalies, chromic and hydrofluoric acids, hydrocarbons, and most alcohols, phenols, esters, and oils. It is nonmagnetic. Galvanic corrosion is an important factor in any assembly with magnesium.
Magnesium is used as a deoxidizer for brass, bronze, nickel, and silver. Because of its light weight, it is used in many weight-saving applications, particularly in the aircraft industry. It is also used in the manufacture and use of fireworks for railroad flares and signals, and for military purposes. Magnesium castings are used for engine housings, blowers, hose pieces, landing wheels, and certain parts of the fuselage of aircraft. Magnesium alloy materials are used in sewing machines, typewriters, and textile machines.
Magnesium can be forged, cast, welded, and machined.
Magnesium in fine chip form will ignite at low temperatures (800 to 1200°F (427 to 649°C)). The flame can be mothered with suitable materials such as carbon dioxide (CO2), foam, and sand.
Pure magnesium has tensile strength of 12,000 psi (82,740 kPa) (cast) and tensile strength of 37,000 psi (255,115 kPa) (rolled); Brinell hardness number of 30 (cast) and 50 (rolled); specific gravity of 1.7; and a melting point of 1202°F (650°C). Magnesium alloy has Brinell hardness number of 72 (hard) and 50 (forged); and tensile strength of 42,000 psi (289,590 kPa) (hard) and 32,000 psi (220,640 kPa) (forged).
Magnesium Metal Tests
CAUTION when testing: Magnesium may ignite and burn when heated in the open atmosphere.
Magnesium resembles aluminum in appearance. The polished surface is silver-white, but quickly oxidizes to a grayish film. Like aluminum, it is highly corrosion resistant and has a good strength-to-weight ratio, but is lighter in weight than aluminum. It has a very low kindling point and is not very weldable, except when it is alloyed with manganese and aluminum. Magnesium is distinguished from aluminum by the use of a silver nitrate solution. The solution does not react with aluminum, but leaves a black deposit of silver on magnesium. Magnesium is produced in large quantities from sea water. It has excellent machinability, but special care must be used when machining because of its low kindling point.
Fracture test: Magnesium has a rough surface with a fine grain structure.
Spark test: No sparks are given off.
Torch Test: Magnesium oxidizes rapidly when heated in open air, producing an oxide film which is insoluble in the liquid metal. A fire may result when magnesium is heated in the open atmosphere. As a safety precaution, magnesium should be melted in an atmosphere of inert gas.
Pure manganese has a relatively high tensile strength, but is very brittle. Manganese is used as an alloying agent in steel to deoxidize and desulfurize the metal.
In metals other than steel, percentages of 1 to 15 percent manganese will increase the toughness and the hardenability of the metal involved.
Manganese is used mainly as an alloying agent in making steel to increase tensile strength.
It is also added during the steel-making process to remove sulfur as a slag. Austenitic manganese steels are used for railroad track work, power shovel buckets, and rock crushers.
Medium-carbon manganese steels are used to make car axles and gears.
Manganese can be welded, machined, and cold-worked.
Austenitic manganese steels are best machined with cemented carbide, cobalt, and high-speed steel cutters.
Pure manganese has tensile strength of 72,000 psi (496,440 kPa) (quenched) Brinell hardness number of 330; specific gravity of 7.43: a melting point of 2270°F (1243°C); and is brittle. Manganese alloy has a tensile strength of 110,000 psi (758,450 kPa). Generally, manganese is highly polishable and brittle.
Pure molybdenum has a high tensile strength and is very resistant to heat. It is principally used as an alloying agent in steel to increase strength, hardenability, and resistance to heat.
Molybdenum is used mainly as an alloy. Heating elements, switches, contacts, thermocouplers, welding electrodes, and cathode ray tubes are made of molybdenum.
Molybdenum can be swaged, rolled, drawn, or machined.
Molybdenum can only be welded by atomic hydrogen arc, or butt welded by resistance heating in vacuum. It is attacked by nitric acid, hot sulfuric acid, and hot hydrochloric acid.
Pure molybdenum has a tensile strength of 100,000 psi (689,500 kPa) (sheet) and 30,000 Psi (206,850 kPa) (wire); Brinell hardness number of 160 to 185; specific gravity of 10.2; meting point of 4800°F (2649°C); retains hardness and strength at high temperatures; and is corrosion resistant.
Nickel is a hard, malleable, ductile metal. As an alloy, it will increase ductility, has no effect on grain size, lowers the critical point for heat treatment, aids fatigue strength, and increases impact values in low temperature operations. Both nickel and nickel alloys are machinable and are readily welded by gas and arc methods.
Nickel is used in making alloys of both ferrous and nonferrous metal. Chemical and food processing equipment, electrical resistance heating elements, ornamental trim, and parts that must withstand elevated temperatures are all produced from nickel-containing metal. Alloyed with chromium, it is used in the making of stainless steel.
Nickel alloys are readily welded by either the gas or arc methods. Nickel alloys can be machined, forged, cast, and easily formed.
Nickel oxidizes very slowly in the presence of moisture or corrosive gases.
Pure nickel has tensile strength of 46,000 psi (317,170 kPa); Brinell hardness number 220; specific gravity of 8.9; and melting point of 2650°F (1454°C). Nickel alloys have Brinell hardness number of 140 to 230. Monel-forged nickel has tensile strength of 100,000 psi (689,500 kPa), and high strength and toughness at high temperatures.
Monel metal is a nickel alloy of silver-white color containing about 67.00 percent nickel, 29.00 to 80.00 percent copper, 1.40 percent iron, 1.00 percent manganese, 0.10 percent silicon, and 0.15 percent carbon.
In appearance, it resembles untarnished nickel.
After use, or after contact with chemical solutions, the silver-white color takes on a yellow tinge, and some of the luster is lost. It has a very high corrosion resistance and can be welded.
- Appearance: Pure nickel has a grayish white color.
- Fracture: The fracture surface of nickel is smooth and fine grained.
- Spark test: In a spark test, nickel produces a very small amount of short, orange streaks which are generally wavy.
Tin is a very soft, malleable, somewhat ductile, corrosion resistant metal having low tensile strength and high crystalline structure. It is used in coating metals to prevent corrosion.
The major application of tin is in coating steel. It serves as the best container for preserving perishable focal. Tin, in the form of foil, is often used in wrapping food products. A second major use of tin is as an alloying element. Tin is alloyed with copper to produce tin brass and bronze, with lead to produce solder, and with antimony and lead to form babbitt.
Tin can be die cast, cold worked (extruded), machined, and soldered.
Tin is not weldable.
Pure tin has tensile strength of 2800 psi (19,306 kPa); specific gravity of 7.29; melting point of 450°F (232°C); and is corrosion resistant. Babbitt alloy tin has tensile strength of 10,000 psi (68,950 kPa) and Brinell hardness number of 30.
- Appearance: Tin is silvery white in color.
- Fracture test: The fracture surface of tin is silvery white and fairly smooth.
- Spark test: Tin gives off no sparks in a spark test.
- Torch test:Tin melts at 450°F (232°C), and will boil under the torch.
Titanium is a soft, silvery-white, medium-strength metal with good corrosion resistance. It has a high strength-to-weight ratio, and its tensile strength increases as the temperature decreases.
Titanium has low impact and creep strengths, as well as seizing tendencies, at temperatures above 800°F (427°C).
Titanium is a metal of the tin group which occurs naturally as titanium oxide or in other oxide forms. The free element is separated by heating the oxide with aluminum or by the electrolysis of the solution in calcium chloride.
Its most important compound is titanium dioxide, which is used widely in welding electrode coatings. It is used as a stabilizer in stainless steel so that carbon will not be separated during the welding operation.
It is also used as an additive in alloying aluminum, copper, magnesium, steel, and nickel; making powder for fireworks; and in manufacturing turbine blades, aircraft firewalls, engine nacelles, frame assemblies, ammunition tracks, and mortar base plates.
Titanium can be machined at low speeds and fast feeds; formal, spot-and seam-welded, and fusion welded using inert gas.
Titanium has low impact strength and low creep strength at high temperatures (above 800°F (427°C)).
It can only be cast into simple shapes, and any gas welding process cannot weld it because of its high attraction for oxygen. Oxidation causes this metal to become quite brittle.
The inert gas welding process is recommended to reduce contamination of the weld metal.
Pure titanium has a tensile strength of 100,000 psi; Brinell hardness number of 200; specific gravity of 4.5; melting point of 3300°F (1851°C); and good corrosion resistance.
Alloy titanium has a Brinell hardness number of 340; tensile strength of 150,000 psi; and a high strength/weight ratio (twice that of aluminum alloy at 400°F (204°C)).
Related: How to Weld Titanium
Titanium is a soft, shiny, silvery-white metal that burns in the air and is the only element that burns in nitrogen.
Titanium alloys look like steel and can be distinguished from steel by a copper sulfate solution.
The solution will not react with titanium but will leave a coating of copper on steel.
The sparks given off are large, brilliant white, and of medium length.
Tungsten is a hard, heavy, nonmagnetic metal that will melt at approximately 6150°F (3400°C).
Tungsten is used in making light bulb filaments, phonograph needles and as an alloying agent in the production of high-speed steel, armor plate, and projectiles.
It is also used as an alloying agent in non-consumable welding electrodes, armor plate, die and tool steels, and hard metal carbide cutting tools.
Tungsten can be cold and hot drawn.
Tungsten is hard to machine, requires high temperatures for melting, and is produced by powered metallurgy (sintering process).
Tungsten has a melting point of 6170 ± 35°F (3410 ± 19°C); is ductile; has tensile strength of 105,000 psi (723,975 kPa); a specific gravity of 19.32; thermal conductivity of 0.397; a Brinell hardness number of 38; and is a dull white color.
Tungsten is steel gray in color.
Spark test: Tungsten produces a very small volume of short, straight, orange streaks in a spark test.
Zinc is a medium low strength metal having a very low melting point.
It is easy to machine, but coarse-grain zinc should be heated to approximately 180°F (82°C) to avoid cleavage of crystals.
Zinc can be soldered or welded if properly cleaned and the heat input closely controlled.
- Galvanizing metal is the largest use of zinc and is done by dipping the part in molten zinc or by electroplating it. Examples of items made in this way are galvanized pipe, tubing, sheet metal, wire, nails, and bolts. Zinc is also used as an alloying element in producing alloys such as brass and bronze. Those alloys that are made up primarily of zinc itself.
- Typical parts made with zinc alloy are die castings, toys, ornaments, building equipment, carburetor and fuel pump bodies, instrument panels, wet and dry batteries, fuse plugs, pipe organ pipes, munitions, cooking utensils, and flux. Other forms of zinc include zinc oxide and zinc sulfide, widely used in paint and rubber, and zinc dust, which is used in the manufacture of explosives and chemical agents.
Zinc can be cast, cold worked (extruded), machined, and welded.
Do not use zinc die castings in continuous contact with steam.
Zinc has a tensile strength of 12,000 psi (82,740 kPa) (cast) and 27,000 psi (186,165 kPa) (rolled); a specific gravity of 7.1; a melting point of 790°F (421°C); is corrosion resistant; and is brittle at 220°F (104°C).
Both zinc and zinc alloys are blue-white in color when polished, and oxidize to gray.
Zinc Metal Tests
Fracture test: Zinc fractures appear somewhat granular.
Spark test: Zinc and zinc alloys give off no sparks in a spark test.