FERROUS METALS Flashcards
In Latin, iron is known as
Ferrum
The metals which contain iron as their main constituent is known as
Ferrous metals
Important ferrous metals are
- Cast-iron
- Wrought-iron
- Steel
The metals which do not contain iron as their main constituent is known as
Non-ferrous metals
Important non-ferrous metals are
- Aluminium
- Copper
A solid naturally occurring mineral aggregate, of economic interest, from which, one or more valuable constituents may be recovered by certain treatment is termed as an
Ore
The impurities present in ore is termed as
Gangue
Iron ore contains
Compounds of iron and non metallic elements
Impurities present in iron ore are
- Carbon
- Manganese
- Phosphorus
- Silicon
- Sulphur
Location where the mines should be easily accessible and they should be linked up with surrounding towns by suitable transport facilities is considered as
Geographical location
Location where site for mines should not contain conditions which might develop complications in quarrying and mining operations is considered as
Geological location
Important commercial varieties of iron ores are
- Magnetite
- Haematite
- Limonite
- Pyrites
- Siderite
Black oxide of iron is
Magnetite (Fe3O4)
Richest ore of iron ore is
Magnetite
Percentage of iron in magnetite is
70-73%
In India magnetite is available at
Madras
Specific gravity of magnetite is
4.9-5.2
Colour of magnetite is
Black
Red oxide of iron is
Haematite (Fe2O3)
Percentage of iron in haematite is
65-70%
Specific gravity of haematite is
4.5-5.3
Colour of haematite is
Black or steel grey
In India haematite is available at
- Mysore
- Madhya Pradesh
Brown haematite is
Limonite (2Fe2O3 3H2O)
Percentage of iron in limonite is
60%
Specific gravity of limonite is
3.6 – 4
Colour of limonite are
- Brown
- Yellowish brown
- Yellow
In India, limonite is available at
Jamshedpur
Sulphide of iron is
Pyrite (FeS2)
Percentage of iron in pyrite is
45-47%
Colour of pyrite are
- Bronze yellow
- Pale brass yellow
Specific gravity of pyrite is
4.8 – 5.1
Pyrite is not used in the manufacture of iron because
Sulphur present in the ore makes it brittle
Carbonate of iron is
Siderite (FeCO3)
Siderite is also known as
Spathic iron ore
Percentage of iron in siderite is
40%
Colour of siderite is
- Pale yellow
- Brownish red
- Brownish black
In India, siderite is available at
Raniganj, West Bengal
The crude impure iron which is extracted from iron ores is known as
Pig-iron
The basic material for the manufacture of cast-iron, wrought-iron and steel is
Pig iron
Manufacturing process of pig iron involves
- Dressing
- Calcination and roasting
- Smelting
In dressing, Iron ores as obtained from mines are crushed into pieces of size of
25 mm diameter
Heating ores below its melting point in the absence or limited supply of air so that they are oxidized is
Calcination
Water and carbon dioxide are removed from ores by
Calcination
Heating ores below its melting point with excess air is termed as
Roasting
The method adopted to dissipate the volatile parts, especially Sulphur, by heat is
Roasting
The extraction of metal from its ore by a process involving heating and melting is termed as
Smelting
Smelting is carried out in a special type of furnace known as
Blast furnace
Dimensional details of blast furnace are
- 30mm-40mm thick
- 6m-8m diameter
- 30m height
Essential parts of a typical blast furnace are
- Throat
- Stack
- Cylinder
- Bosh
- Hearth
- Tuyeres
- Feeding arrangement
The part located near top portion of the furnace which is the feeding zone or mouth is
Throat
The part which extend from throat to cylinder, having a height of 18m is
Stack
Stack is also known as
Inwall
The angle of inclination of stack varies from
85 degree to 87 degree
The part which connects stack and bosh is
Cylinder
Cylinder is also known as
Barrel
The ratio of total height of furnace to diameter of cylinder should be about
4.00 to 4.50
The burning zone of furnace is
Bosh
The part located between the cylinder and hearth is
Bosh
The bosh has an inward slope and it varies from
76 degree to 80 degree
The height of bosh is about
15 to 20 per cent of the total height of blast furnace
The lowest part of furnace is
Hearth
Hearth is also known as
Crucible
Height of hearth is about
2m to 3m
The part located in the bosh portion of furnace is
Tuyere
The nozzle for a blast of air is
Tuyere
Main varieties of pig iron are
- Bessemer pig iron
- Grey pig iron
- White pig iron
- Mottled pig iron
Bessemer pig iron is obtained from
Haematite ore
Bessemer pig iron is used in the manufacture of
Steel
The pig iron produced when the furnace is provided sufficiently with fuel and the raw materials are burnt at a very high temperature is
Grey pig iron
Soft variety of pig iron mainly used for cast-iron castings is
Grey pig iron
The pig iron produced when the furnace is not provided with sufficient fuel or when the raw materials are burnt at low temperature or when ore or fuel contains a higher percentage of sulphur is
White pig iron
White pig iron is known as
Forged pig iron
Hard and strong variety of pig iron is
White pig iron
The variety of pig iron used in the manufacture of wrought-iron is
White pig iron
The type of pig iron which is strong and contains a large proportion of combined carbon is
Mottled pig iron
The variety of pig lies somewhere between grey pig and white pig is
Mottled pig
The type of pig used for heavy foundry castings is
Mottled pig iron
A material which easily breaks into pieces or which can be easily reduced to powder form is known as a
Brittle material (eg: Glass)
A material which can be drawn into fine wires is known as a
Ductile material (eg: Silver and copper)
A material which cannot be cut by a sharp tool is known as a
Hard material (eg: Diamond)
A material which can be beaten into thin sheets or leaves is known as a
Malleable material (eg: Gold)
A material which can be easily cut by a sharp weapon is known as a
Soft material (eg: Lead)
A material which does not easily break under a hammer is known as a
Tough material (eg: Basalt)
Remelting pig-iron with coke and limestone gives
Cast iron
The remelting pig-iron with coke and limestone is done in
Cupola furnace
Cupola furnace is cylindrical in shape with diameter and height
- 1m
- 5m respectively
Molten cast-iron is led into moulds of required shapes to form
Cast-iron castings
Percentage of carbon in cast iron is
2-4%
Various impurities present in cast iron are
- Manganese
- Phosphorus
- Silicon
- Sulphur
Varieties of cast iron are
- Grey cast iron
- White cast iron
- Mottled cast iron
- Chilled cast iron
- Malleable cast iron
- Toughened cast iron
Grey cast iron is prepared from
Grey pig iron
Grey cast iron is
Soft and weak in strength and is grey in colour
Grey cast iron is used extensively in making
Castings
The colour of white cast iron is
Silvery white
White cast iron is
Hard
An intermediate variety between grey cast-iron and white cast-iron is
Mottled cast iron
Mottled cast iron is used for
Small castings
The variety of cast iron used to provide wearing surface to castings are
Chilled cast iron
Making some portion of cast-iron hard and other portion soft is
Chilling
Cast-iron is so adjusted that it becomes malleable by extracting a portion of carbon from cast-iron in
Malleable cast iron
Malleable cast iron is used for
- Railway equipment
- Automobiles
- Pipe fittings
- Agricultural implements
- Door fastenings
- Hinges
The variety of cast-iron is obtained by melting cast-iron with wrought-iron scrap is
Toughened cast iron
The proportion of wrought-iron scrap is about
1/4 to 1/7th of weight of cast-iron
Melting temperature of cast iron is about
1250 degree Celsius
Tensile and compressive strengths of cast-iron of average quality are respectively
- 1500 kg/cm2
- 6000 kg/cm2
Various types of casting are
- Centrifugal casting
- Chilled casting
- Die casting
- Hollow casting
- Sand casting
- Vertical sand casting
The type of casting, molten metal is poured into moulds which are kept rotating is
Centrifugal casting
Centrifugal casting is used to prepare
Pipes
The type of casting in which outer surface is made hard by sudden cooling or chilling and the inner surface remains comparatively soft is
Chilled casting
The type of castings adopted to produce wearing surface as in case of tyres and axle holes of railway carriage wheels is
Chilled casting
The type of casting in which molten metal is poured into metal moulds under pressure is
Die casting
The castings which are cheap, smooth and compact is
Die casting
The type of casting in which the mould is made as usual and a solid core is suspended in the middle of mould to form cavity is
Hollow casting
Hollow casting is used for preparing
- Hollow columns
- Pipes
- Piles
The type of casting in which sand mould and solid core are held in a vertical position is
Vertical sand casting
Vertical sand casting is used to prepare cast-iron pipes for
Carrying water under pressure
Major defects in casting are
- Cold short
- Drawing
- Holes
- Honey combing
- Lifts and shifts
- Scabbing
- Swelling
The defect formed at the junction where two streams of molten metal meet is
Cold short
The defect formed when the metal becomes solid before the mould is completely filled up is
Drawing
If vent holes are insufficient, air and gases become entrapped and it ultimately results in porous casting with holes. Such defect is known as
Holes
The defect occurring due to the fusing of surface sand is termed as
Honeycombing
The external defects of casting due to misplacement of core is
Lifts and shifts
The defect in which scales are seen on the casting due to heavy sand which sticks to casing is
Scabbing
The defect occurring when mould is not properly rammed is
Swelling
The percentage of carbon content in wrought iron is
Not more than 0.15%
The operations involved in the manufacture of wrought iron are
- Refining
- Puddling
- Shingling
- Rolling
Pig-iron is melted and a strong current of air is directed over it. It is then stirred, oxidized and suddenly cooled to obtain
Refined pig iron
Conversion of pig-iron into wrought-iron by stirring in a molten state is known as
Puddling
Puddling is carried out in
Reverberatory furnace
The purified iron becomes thick and it assumes the form of white spongy iron balls. These are known as
Puddle balls
Weight of each puddle ball is about
50kg to 70 kg
The operation in which the slag contained in puddle balls is removed by forging the balls under a power hammer or by passing the balls through squeezing machine is
Shingling
The material obtained at the end of shingling is known as
Bloom
The process in which the bloom is passed through grooved rollers is termed as
Rolling
The bloom is passed through grooved rollers and flat bars of size about
- 4 m
- 10 cm
- 25 mm
The process of manufacturing of wrought iron is
Aston’s process
Melting point of wrought iron is
1500 degree Celsius
Specific gravity of wrought iron is
7.8
Ultimate compressive strength and ultimate tensile strength are
- 2000 kg/cm2
- 4000 kg/cm2
When the amount of phosphorus is excess in wrought iron, the defect occurred is
Cold short
When the amount of sulphur is excess in wrought iron, the defect occurred is
Red short
Wrought iron is used for
- Rivets
- Chains
- Ornamental iron work
- Railway couplings
- Water and steam pipes
- Raw material for manufacturing steel
- Bolts and nuts etc.
