Mechanical World

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 guillotine, springs, etc.     Stainless Steel 4.       Stainless steel: are iron and ch

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 weak in tension and strong in compression.     ix.             This is not suitable for shock and impact loads.       x.             It has a specific gravity of 7.5, and it has a melting point of 1250°C.     xi.             It has good machinability property. Uses of Cast Iron:          i.             Used for water and gas pipes.        ii.             It is used in manufacturing of cisterns, sewer and drain pipes, manhole covers and fittings.      iii.             Used for rail chairs, carriage wheels, etc.      iv.             U

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 elements used a

Types of Cast Iron: Following are the common types of Cast Iron used in engineering materials. 1. Grey Cast Iron:   Gray Cast Iron Grey forged iron is produced by melting the foundry iron or grey iron within the cupola furnace. It shows grey color when fractured. The grey color is due to the presence of free graphite. The composition of Grey Cast Iron is: i.           Iron – 92 percent. ii.          Carbon – 3 to 3.5 percent (as graphite). iii.         Carbon – 0.5 percent (combined). iv.         Silicon – 1 to 2.75 percent. v.          Manganese – 1 percent. vi.         Phosphorus – 0.5 to 1 percent. vii.        Sulfur – 0.02 to 0.15 percent. 2. White Cast Iron:   White Cast Iron It is white in color as there's no free graphite. In white Cast Iron, the entire carbon is in combined state. i.e., in the form of cementite, also known as Iron carbide. White Cast Iron is produced by melting the low phosphorus Pig Iron along with the Steel scraps

Types of Ferrous Metals: Following are the 4 common types of Ferrous Metals: 1. Pig Iron 2. Wrought Iron 3. Cast Iron 4. Steel 1. Pig Iron:  Pig Iron Pig Iron is that the first or basic form during which Iron is ready because the metal from its ores. It is, therefore, impure and crude and requires subsequent processing to develop Cast, Wrought Iron, and Steel, which are the common Ferrous Metals used in construction and industries. 2. Wrought Iron:   Wrought Iron It is the purest form of Iron, containing all impurities below a limit of 0.5 percent. And carbon is included in these impurities, its proportion being generally less than 0.12 percent. Besides, Wrought Iron always contains a small proportion of slag in the silicate component. The source material for the manufacture of Wrought Iron is Pig Iron. 3. Cast Iron:  Cast Iron Cast Iron is derived from the Pig Iron. Pig Iron, due to its impurities, is weak and hence very difficult to shape

Types of metals: Metals are often divided into two main groups: ferrous metals are those which contain iron and non-ferrous metals that are those which contain no iron. Ferrous Metals:   Ferrous Metals Pure Iron is of little use as an engineering material because it's too soft and ductile. When iron cools and changes from a liquid to a solid, most of the atoms within the metal pack, tightly together in orderly layers. Some, however, Become misaligned, creating areas of weaknesses called dislocations. When a bit of iron is anesthetize stress, layers of atoms in these areas slip over each other and therefore the metal deforms. This begins to elucidate the ductility of sentimental iron. By adding carbon to the iron however, we will produce a variety of alloys with quite different properties. We call these the carbon steels. An alloy may be a mixture of two or more chemical elements and therefore the primary element may be a metal. Non-Ferrous metals:   Non-F

Types of chips: Following are the three common types of chip from a single point tool:  1.   Continuous Chips : Continuous chips are formed by the continual plastic deformation of metal without fracture ahead of the leading edge of the tool and is made by the graceful flow of the chip up the tool face. MS steel and copper are considered to be most desirable materials for obtaining continuous chips. The chips obtained have same thickness throughout. This type of chip is the most desirable. Since its stable cutting, leading to generally good surface finish. On the opposite hand these chips are difficult to handle and dispose off. Continuous chips tend to be formed when the subsequent condition exist: • Ductile material • High cutting speed • Small chip thickness • Large rack angle 2. Discontinuous or Segmental chip: This type of chips are made by a series of rupture occurring approximately perpendicular to the tool place face each chip