Non-ferrous metals and alloys do not contain significant amounts of iron. The most common non-ferrous metals used in engineering applications are copper, aluminum, tin, lead, and zinc. Nickel, Magnesium, and antimony are also used to alloy the non-ferrous metals mentioned above.
Properties and Uses of Non Ferrous Metals
Copper is a corrosion-resistant metal with an attractive reddish-brown color and is an extremely good conductor of heat and electricity. It can also be drawn into wires and beaten into sheets and plates. Therefore, it is widely used in the electrical industry for making armature coils, field coils, and current-carrying coils. wires, household utensils, etc.
But its great utility lies in the fact that it is alloyed with zinc, tin, and Nickel and produces brass, bronze, and cupro-nickel respectively, which are widely used in the engineering industry. Copper, as such, is used for many decorative elements. Not much copper is available in India. India imports at least 50-60% every year.
Metallic aluminum is difficult to extract from its main mineral called bauxite. Even then, Bauxite is available in abundance in India. It is also very resistant to corrosion (as an adherent oxide layer protects it from further oxidation). This again a very good conductor of heat and electricity (though not as good as Cu). is ductile and
Malleable and much cheaper than copper.
Therefore, it has almost replaced copper wires for the transmission of electricity. It is also used for household utensils including pressure cookers. However, since it may be converted into thin sheets, it is now widely used in the beverage cans and packaging industry. The density is about one-third that of steel, so it is also used in aircraft and helicopter frames and transportation vehicles. Aluminum forms a range of alloys with magnesium, which are harder and more resistant than pure ones.
It has an attractive silvery white color. It has very good resistance to acid corrosion. Before the advent of thin gauge tin and plastic-coated steel sheets, they were used to manufacture tin cans for storage of ghee, mustard, and other oils. Today, tin is mostly used for alloying purposes. Tin and lead combine together to give a range of soft solder. The melting point of tin is low.
Lead is a heavy metal that is light gray in color. It has good corrosion resistance and it has good flexibility. In Europe, it was widely used for roof protection. It was also used in plumbing. It can withstand sulfuric acid and be previously stored in lead-lined containers. It possesses Self-lubricating properties. That’s why it was used in lead pencils.
Small amounts of lead are sometimes added to steel and bronze to provide free-cutting properties.
Zinc has a blue-grey metallic form. It has high resistance to corrosion. Steel sheets are usually covered with a thin layer of zinc. Such zinc-coated sheet is known as galvanized Iron sheets (GI sheets). Zinc coating provides protection to steel sheets against corrosion for many years.
Zinc has a low melting point and high fluidity, making it suitable for objects produced by the die casting process. By the way, zinc is much cheaper than copper or tin; made of brass, alloy Copper and zinc are much cheaper than copper or tin bronze. Zinc is also used in flashlight batteries.
Alloy of Brass
Brass is an alloy of copper and zinc. Commercially, two types of brass are most important:
It contains up to 36% zinc and the rest is copper.
It contains 36% to 46% Zn, the rest being copper.
Alpha and beta are the names given to the different phases of brass. alpha-beta brass has both
alpha and beta phases. Increasing Zn content up to 30% increases the tensile strength and ductility of brass
Zinc. If the zinc content is increased beyond 30%, the tensile strength increases up to 45% Zn, but there is a marked decline in the elasticity of brass. The β beta phase is very hard and strong but less ductile than the α phase. The α phase has excellent cold formability and is used when parts are molded into shapes. The mechanical properties of α-phase also change with the amount of cold work done on them.
Bronze is an alloy of copper and tin, although commercial bronze may contain other elements besides
tin. In fact, alloys of copper with aluminum, silicon, and beryllium, which may not contain tin, are also known as bronze.
Tin Bronze is a beautiful golden color. As brass, both tensile strength and ductility increase with an increase in tin content. However, in bronze, no more than 10% tin is used. As a result, the brittle intermetallic compound Cu3Sn is formed. Tin content in copper increases strength, hardness, and durability to a great extent compared to zinc addition to copper.
The following varieties of tin bronze are commonly used:
(i) Phosphorus-Bronze. Tin bronze is produced by adding 0.5% phosphorus to phosphor bronze. Phosphorus increases the fluidity of molten metal and can give fine casting to be made.
(ii) Lead Bronze. Lead bronze is produced by adding lead to tin bronze. It is indeed a source of weakness, but it enhances machinability and has self-lubricating properties. Typically, the percentage of lead does not exceed 2%.
(iii) Gun metal. It contains 2% zinc, 10% tin, and 88% copper. This is a very famous creation. This brass is used for bushings, stuffing boxes, pumps, valves, etc.
(iv) Metal bell. It is a tin bronze but with a much higher percentage (20–25%) of tin.
Bronze that does not contain tin. The following bronzes do not contain tin and are known commercially:
(i) Aluminum Bronze. Composition: 14% aluminum, the rest copper. good strength and good corrosion resistance. Colour: Golden Yellow. It is often used for costume jewelry.
(ii) Silicon bronze. Composition: 1-4% silicon, the rest mainly copper. very nice owner corrosion resistance. It can be cold-worked and hardened. It is used for the installation of boilers and Marine Goods.
(iii) Manganese bronze. Composition: 40% zinc and 55-60% copper with 3-5% manganese. It is essentially a brass to which manganese has been added. It is used for the ship’s propeller.
(iv) Beryllium Bronze. Beryllium is very expensive. It is an alloy. It contains about 2% Be. It possesses very good mechanical properties and can be cold-worked and age-hardened. It is mainly used for Bellows, Bourdon Gauge Tubes, etc.
Frequently Asked Questions
Brass is an Alloy of?
Brass is an alloy of copper and zinc.
What is the difference between brass and bronze?
Both are combinations of different metals. Brass is made of copper and zinc, whereas bronze is made up of copper and tin.
Also, Read about Moulding Sand