Flashcards in Types Of Iron And Production Methods Deck (9)
What is the name of the talcum-fine particles produced in processing plants near iron mines that crush and grind rock ore to find iron rich ______
What is the parallel recovery process called that occurs at the iron and steel plants? And how big do they fuse the particles of iron that are put into the blast furnace?
Iron rich "fines"
"Sintering" and 6mm (1/4in)
What are the 3 materials added into a blast furnaces to make iron and what do they do
Iron ore, coke and limestone
Coke is added to heat the blast furnace (byproduct of coal) and limestone operates as a fluxing agent to remove impurities from the molten iron. These impurities form a layer of slag on top of the iron.
What is another name for the insulated iron transfer cars?
What are the 4 main types of cast iron?
Grey cast iron
White cast iron
Nodular (ductile iron)
Explain what alloys are in grey cast iron and how its formed
How is it identified?
Grey cast iron has a high silicon content. Usually cooled in sand moulds. The silicon is dissolved in the iron ferrite and combined with the carbon to form graphite. It is the separation of the carbon from the iron that makes grey cast iron brittle.
Identified when broken by the dark grey flecks of graphite and the porous grain structure
How is white cast iron cooled and what is the resulting compound called? What is it generally considered and what can it be used for?
Usually cooled more rapidly than grey cast iron, usually in steel moulds. Because the cooling is rapid, the carbon does not separate from the iron. The resulting compound is called "cementite" and it is very hard and brittle. White cast iron is generally considered unweldable and has very few applications in its original state.
White cast iron is usually used on the outer surface of castings where extreme hardness and wear resistance are required.
How is Malleable iron made and what is it used for?
Malleable iron is white cast iron that has been subjected to a long annealing process (heating and cooling slowly). Thus process removes the brittleness from the casting and leaves the metal softer but with considerable toughness and strength.
The fracture of a piece of Malleable cast iron will show a white rim with a dark centre. Has a higher tensile strength than grey cast iron.
Explain how Nodular iron is made and what makes it better
Nodular iron has the ductility of Malleable cast iron, the corrosion resistance of grey cast iron and a greater tensile strength than grey cast iron.
Nodular iron is obtained by adding a small amount of magnesium to the iron at the time of melting. This causes a vigorous mixing reaction and this, along with a controlled cooling rate, causes the graphite to change from a stringer structure (like in grey cast iron) to rounded masses in the form of spheroids (balls). This structural change is the main reason for the greater ductility of nodular iron.
What is the product of a blast furnace called?