Steel making Flashcards
Puddling furnace.
Molten pig iron is poured and reaches a reverberatory furnace with coals in it. Walls are lined with oxides to protect from burning. Hot air is then added causing heated air to oxidize the impurities. C0 and C02 form which causes the mixture to form bubbles and have a boiling appearance. Slag is formed. impurities with element excess c02 are blown away through the chimney.
Early procces to produce iron. heats metal partially and below metling point
Clay crucible. Clay does not heat up as easily. Wrought iron pieces poured into the crucible and then heated for many days. heated below melting point. hot enough for carbon diffusion.
Besssemer Procccess.
Molten pig iron is poured along with a flux into cylindrical converter Air is blown up underneath. this causes the oxidation of manganese and silicon found in impurturtuties and exhaled either as gas or solid slag. Carbon Monoxide exhaled as blue gas. converts pig iron into cast iron.
What is the use of checker bricks?
To store heat used in preheating procces of open hearth in chambers underneath.
Bowing
When the bessemer conveter is turned upright and air is blown from the bottom
What elements caused the bessemer procces to be not as effective making steel
Phosphourous and sulfur
Reverberatory furnace
does not contain a firepit. Ore is not in direct contact with the fuel source. in steelmaking also called open hearth proccess
Trapping
Pour the molten metal onto something. used in bessemer process when the converter turns sideways to pour the iron out.
Open hearth furnace
Iron as well as limestone, scrap metal, and iron ore are added into the checker bricks chambers for heating. valve is then heated and then combustion air is added. Reverse air is added. metal is heated and creates a bubbling boiling motion.
What is a refractory material
Means it is resitant to the decompostion by heat and retains it’s rigidity at high temperatures. often made with oxides.
output of puddling furnace
Bar iron ( a type of very pure wrought iron). also called puddled steel.
Blast Furnace
Raw materials are inserted (limestone, iron ore, coke are inserted). Carbon dioxide is then produced. Metals are reacting with air in dipping metal producing Carbon Monoxide and impurities from the impure metal. also slag is formed from oxides.
Integrated steel process
Raw material comes in one door and the finished product comes through the other door.
Output of Blast furnace
Pig iron
Basic Oxygen Furnace
Uses liquid oxygen to produce a super sonic air flow to react with the metal. Molten metal in inserted. Gases such as C02 nadn CO are exhaled and placed into separate chambers for other uses.
Steel Mini mill.
uses steel scrap as raw material. Has EAF as main stell conversion. uses EAF. Proudces less steel and mostly alloys
Fuel Source of EAF
Carbon Electrodes and DC electric current.
Ladle Mettalurgy
they are used to refine including deoxidizing, and decarbonizing the molten metal from EAF.
Ladle Mettalurgy purposes
Remove slag and other chemical impurtutruties. Controll tempeture fro casitng operations.
Continous Casting steps
Used at end of steelmaking proccess. 1. ladle. Skip controls
Integrated steel mills
Used for the enitierity of the steel making process. Uses mostly Blast and BOF furnaces. Iron ore and coke enter the facility converted to molten pig iron in Blast furnace. Molten pig iron and scrap materials enter BOF to reduce carbon levels and produce steel. Molten material then enters ladle for refining process. Final stage is contnous casting cooling and producing thick slabs of steel
Ingot method
- Teeming: poured molten metal into ladel2. Stripping: remove ingots from ingot molds 3. Rolling: compressed ingots for desired shapes
Desired teaming procces for pouring molten metal
Bottom pouring
Ingot method Rolling
Metal sheeets are compressed between tow rollers at a high speed. Either hot or cold. Quenching is a cold method.
Contrnous castinf
Bypasses the ingot procces and produces a continuous length of steel.
CC 3 method
Curved mold
Steel micro mills
Uses EAF. Direct iron only
Steel is _ C Cast Iron is
> 2.0 % <2.0 %
Melting poitn of the steels and cast iron
S: 2700-2900 CI: 2100-2300 f
Steels properties are mostly determined by _. Cast iron properties are determined by
Alloys.
Phase Diagrams
Graphical representation of the phases present in an alloy at different conditions of temperature, pressure, or chemical composition.
Fe0c phase diagram
2d diagram of
Euctectic transormation
L CHnaged Austentite + Fe3C. 1130 C
Eucteloid Transformation
Y changes to a =Fe3c. 723 C
Peritectic point
Delta iron - Liquid + Austneite
What is the difference between Hot and Cold Roling.
Hot rolling the ingot is rolled above its recrystallization temperature( which the metal’s lattice structure changes shape). In cold rolling, it is below that and is allowed to cool at room temperature and annealed. cold rolling is used when dimensions and tolerances are more strict.
what is the preffered method of Contnonous casting
Curved method. Metal is transferred into a and then moves throughout the tube being cooled by the wall coolers. rollers are used to curve the slab into a
Stripping
Metals are reduced to proper length. cooled only partially.
Soaking
put in soaking pits. used to prevent elements from segregating from the center to the top.
How open hearth furnace is different from Bessemer process reasons
- Higher quality of steel 2. Can use lower grade charge material 3. Composition of steel can be controlled 4. As no blast of air is used, there will be no loss of iron
low, medium, high Carbon percentage
0.05-0.35, 0.35-0.50
