Mechanical World

Types of Heavy Weight Metals: Copper (Cu):  Copper It is probably the primary engineering metal to be used. Unlike other metals, it can occur in nature within the metallic form also as an ore. It has excellent heat and electrical conductivity and resists to corrosion when alloyed with other metals. However, thanks to lower density, aluminum has higher conductivity per unit weight. Zinc (Zn):  Zinc Zinc is an inexpensive material with moderate strength. It is chemically similar to magnesium. Mechanically zinc is more ductile but not as strong. Although its metal and alloy forms are important, zinc is most commonly used to extend the life of other materials such as steel (galvanizing), rubber and plastic (as an aging inhibitor), and wood (in paint coatings). The zinc-base alloys have an important place as a die-casting metal as it has low melting point (419.5 ºC) which does not affect steel dies adversely, and hence it can be made into alloys with good ...

Light weight Metals: Light weight of certain non-ferrous metals is of special importance in aircraft and space industry. Zinc, tin and lead (with low melting points) are utilized in special applications. Tungsten, molybdenum and chromium are utilized in products that have got to resist high temp. Nickel and cobalt also are suitable as heat resistant alloys. Precious metals (with high cost) aren't only utilized in jewelry, but also in many applications requiring high electrical conductivity and corrosion resistance. The border of light and heavy metals is around 5000 kg/m3. Metals densities below 5000 kg/m3 are called light metals. The lightest metal is Lithium (density 530 kg/m3) whereas the heaviest metal is Osmium (with density of 22500 kg/m3). Steel has a density of 7800 kg/m3. Aluminum (Al):   Aluminum It is probably the most important non-ferrous metal. It has outstanding physical properties (e.g. light weight, high thermal and electrical conductivity,...

History of non-ferrous Metals:  Bronze Age The first non-ferrous metals entered man’s life ever since hoary antiquity as gold and copper, as they occur naturally during a native state. Relatively later began the assembly and use of tin and lead and their copper alloys. This period of historical development, directly associated with the assembly of metals and therefore the production of tools from them, is understood because the Bronze Age and is characterized by a rapid development of the material culture of people and important social changes in human society. Types of non-ferrous Metals: Following are the types of non-ferrous metals: 1. Lightweight non-ferrous metals – Aluminum, Magnesium, Titanium, etc. with a density of less than 4,500 kg/m3 2. Heavy weight non-ferrous metals – Lead, Copper, Nickel, Tin, Antimony, etc. with a density of more than 4,500 kg/m3 3. Precious metals – Gold, Silver and Platinum metals 4. Rare metals –These include 55 met...

Properties and Uses of Carbon Steels:     Mild Steel 1.      Mild Steel:  Carbon content between 0,1% and 0,3%. Properties:  Less ductile but harder and tougher than iron, grey colour, corrodes easily. Uses:  Girders or beams, screws, nut and bolts, nails, scaffolding, car bodies, storage units, oil drums.     Medium Carbon Steel 2. Medium Carbon Steel:  Contains between 0,3% and 0,7% carbon. Properties:  Harder and fewer ductile than low-carbon steel , tough and have a high lastingness . Use:  It's used for the manufacture of products which have to be tough and hard wearing like gears, tools, keys, etc.     High Carbon Steel 3.       High Carbon Steel:  Contains between 0,7% and 1,3% carbon. Properties: Very hard and brittle material. Uses: It's used for cutting tools and products which have to withstand wear such as guillotin...

Properties and Uses of Wrought Iron:   Wrought Iron Its most important properties are mentioned below. 1. Strength: It has a tensile strength varying between 2500 to 4000 kg/cm2. The strength are going to be greater within the longitudinal direction. The ultimate compressive strength ranges between 1500-2000 kg/cm2.   2. Physical: Wrought Iron is bluish in color, has a silky luster and fibrous structure. It is malleable, ductile, tough, and immune to corrosion.   3. Density: The metal has a density of 7.8 gm/cm3 and a melting point of 1500 centigrade. Wrought Iron shows good resistance to fatigue and sudden shock. Moreover, it can be welded with ease. Uses of Wrought Iron: Because of the above set of properties, Wrought Iron is extensively used as a material for making plates, sheets, pipes, tubes, etc. It is also used in buildings, railways, and marine industries.

1. General Properties of Cast Iron:         i.             This is hard and brittle.       ii.             This can be hardened but cannot be tempered.     iii.             This cannot be forged, welded, or riveted.    iv.             This cannot be magnetized.      v.             This does not rust easily.    vi.             It becomes soft in saltwater.   vii.             It shrinks easily. viii.             This is...

Types of Cast Iron: 4. Ductile Cast Iron:  Ductile Cast Iron It is a modified Grey Cast Iron. It is also called as nodular or spheroid graphite Cast iron or high strength forged iron. Ductile forged iron is produced by adding anybody of the weather of magnesium, calcium, cerium, bismuth, zinc, cadmium, titanium, and boron into the molten Grey forged iron. Composition of ductile Cast Iron is as follow: i. Carbon – 3.2 to 4.5%. ii. Silicon – 1 to 4%. iii. Magnesium – 0.1% to 0.8%. iv. Phosphorus – 0.1%. v. Iron – the rest % is Iron. 5. Alloy Cast Iron:   Alloy Cast Iron Alloy Cast Irons are also called as plain Cast Irons. Alloyed forged iron s are produced by adding the alloying elements to the iron within the cupola furnace itself or adding an equivalent into the molten Cast Iron taken out of the furnace. Better results are obtained when iron with alloying elements are heated in an electrical furnace or air furnace. The alloying elemen...