Steel Making
Refer to the material provided and answer the questions. This quiz has to be answered before 23:59 hrs of 21st May. Each correct answer will fetch you three points. There is negative marking of one point for each wrong answer
Questions and Answers
- 1.
In the BOF(Basic Oxygen Furnace) process pure ______ at supersonic speed is blown vertically through a lance onto the surface of hot molten metal contained in a cylindrical-shaped converter.
- A.
Oxygen
- B.
Hydrogen
- C.
Neon
- D.
Carbon dioxide
Correct Answer
A. OxygenExplanation
In the BOF process, pure oxygen is blown at supersonic speed through a lance onto the surface of hot molten metal. This is done in a cylindrical-shaped converter. The purpose of blowing oxygen onto the metal is to remove impurities and increase the purity of the metal. Oxygen is used because it reacts with the impurities in the metal, forming oxides that can be easily removed. Hydrogen, neon, and carbon dioxide do not have the same reactivity and therefore cannot effectively remove impurities from the metal.Rate this question:
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- 2.
An important advantage of Bottom Blowing processes is that they operate ____________
- A.
At the equilibrium
- B.
Closer to equilibrium
- C.
Farther from the equilibrium
Correct Answer
B. Closer to equilibriumExplanation
Bottom blowing processes operate closer to equilibrium. This means that the conditions during these processes are optimized to achieve a balance between reactants and products, resulting in a more efficient and effective operation. Operating closer to equilibrium allows for better control of the reaction and minimizes the formation of unwanted byproducts. This advantage ensures that the process is more stable and yields higher quality results.Rate this question:
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- 3.
Blowing of Oxygen under vacuum is the technique used to produce ______________
- A.
High Carbon steels
- B.
Low Carbon steels
- C.
Medium Carbon steels
- D.
ULC steels
Correct Answer
D. ULC steelsExplanation
Blowing of oxygen under vacuum is a technique used to produce Ultra Low Carbon (ULC) steels. This process helps in reducing the carbon content in the steel to extremely low levels, typically below 0.01%. ULC steels are highly desirable for various applications due to their excellent formability, weldability, and resistance to embrittlement. By removing excess carbon, ULC steels exhibit improved ductility and toughness, making them suitable for industries such as automotive, construction, and manufacturing.Rate this question:
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- 4.
The reactions involving the oxidation of metalloids are highly endothermic.
- A.
True
- B.
False
Correct Answer
A. TrueExplanation
The oxidation of metalloids refers to the process of combining with oxygen, which requires the input of energy. Endothermic reactions are those that absorb heat from their surroundings. Therefore, it can be inferred that the oxidation of metalloids is highly endothermic, meaning it requires a significant amount of energy to occur.Rate this question:
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- 5.
The exit gas generated during blowing is rich in ____________
- A.
Oxygen
- B.
CO
- C.
COâ‚‚
- D.
SOâ‚‚
Correct Answer
B. COExplanation
During blowing, when a substance is heated, it undergoes a chemical reaction with oxygen in the air. This reaction produces carbon monoxide (CO) as a byproduct. Therefore, the exit gas generated during blowing is rich in CO.Rate this question:
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- 6.
The converter contents often overflow through the tap hole or get ejected through the mouth opening and this is referred to as spitting (for metal droplets) or slopping (for slag-metal emulsion).
- A.
True
- B.
False
Correct Answer
A. TrueExplanation
The statement is true because in a converter, the contents can overflow through the tap hole or get ejected through the mouth opening, leading to spitting or slopping. Spitting refers to the ejection of metal droplets, while slopping refers to the emulsion of slag and metal.Rate this question:
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- 7.
The Basic Oxygen Steelmaking (BOS) process takes this liquid iron plus recycled scrap steel, and reduces the carbon content to ___________ by blowing oxygen through the metal in a"converter".
- A.
0 to 2 percent
- B.
0 to 1.5 percent
- C.
1.5 to 2.5 percent
- D.
1 to 1.5 percent
Correct Answer
B. 0 to 1.5 percentExplanation
The Basic Oxygen Steelmaking (BOS) process involves reducing the carbon content in the liquid iron by blowing oxygen through the metal in a "converter". The correct answer is 0 to 1.5 percent because this range represents the desired carbon content after the process is completed. By blowing oxygen through the metal, the carbon reacts with the oxygen to form carbon monoxide and carbon dioxide, thereby reducing the carbon content in the iron. The BOS process is an important step in steel production as it allows for the production of high-quality steel with the desired carbon content.Rate this question:
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- 8.
Steel making process occurs at approximately ______________
- A.
1500 degrees Celsius
- B.
1600 degrees Celsius
- C.
1700 degrees Celsius
- D.
1800 degrees Celsius
Correct Answer
B. 1600 degrees CelsiusExplanation
The steel making process occurs at approximately 1600 degrees Celsius. This high temperature is necessary to melt the raw materials, such as iron ore, and to remove impurities through chemical reactions and physical processes. At this temperature, the iron becomes molten and can be further processed to remove impurities and adjust its composition to produce different types of steel.Rate this question:
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- 9.
Which of these is a raw material in steel making?
- A.
Iron Ore
- B.
Coke
- C.
Limestone
- D.
All of these
Correct Answer
D. All of theseExplanation
All of these options are raw materials used in steel making. Iron ore is the primary source of iron used in steel production. Coke is a fuel made from coal that is used to heat the iron ore and produce carbon monoxide, which reacts with the iron to remove impurities. Limestone is used as a fluxing agent to remove impurities from the molten iron and help in the formation of slag. Therefore, all three options are essential raw materials in the steel making process.Rate this question:
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- 10.
Bismuth is injected in deep cutting steels to improve machinability.
- A.
True
- B.
False
Correct Answer
B. FalseExplanation
Bismuth is not injected in deep cutting steels to improve machinability.Rate this question:
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- 11.
In a steel alloyed with aluminium(Al 'killed'), if the ladle top slag is ______ (high levels of FeO and MnO), then aluminium in the steel can react with 'oxygen' in the slag to form hard alumina inclusions in the steel which are detrimental to product properties.
- A.
Highly oxidized
- B.
Highly reduced
Correct Answer
A. Highly oxidizedExplanation
When the ladle top slag in a steel alloyed with aluminium is highly oxidized (with high levels of FeO and MnO), the aluminium in the steel can react with the oxygen in the slag. This reaction forms hard alumina inclusions in the steel, which are detrimental to the product properties.Rate this question:
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- 12.
During steel casting, the steelmaking ladle is emptied through a valve in the bottom of the ladle; as the ladle gradually empties, the ladle top slag coats and solidifies on the side walls of the ladle, and remains there once the ladle is empty. This is termed as ___________
- A.
Rolling
- B.
Steel making
- C.
Steel glazing
- D.
Steel brazing
Correct Answer
C. Steel glazingExplanation
During steel casting, the ladle top slag coats and solidifies on the side walls of the ladle, creating a smooth and shiny layer. This process is similar to glazing, where a glossy coating is applied to a surface. Therefore, the term "steel glazing" accurately describes this phenomenon.Rate this question:
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- 13.
In ladle stirring, Stokes' law to estimate the float rate, u of a particle. This law is applicable only for __________
- A.
Cuboidal particle
- B.
Spherical particle
- C.
Pyramidal particle
- D.
Any particle
Correct Answer
B. Spherical particleExplanation
Stokes' law is applicable only for spherical particles. This law states that the drag force acting on a particle in a fluid is directly proportional to the velocity of the particle and the viscosity of the fluid, and inversely proportional to the radius of the particle. Since the law is derived based on the assumption of a spherical shape, it is only valid for spherical particles. Other particle shapes, such as cuboidal or pyramidal, would have different drag forces and therefore cannot be accurately estimated using Stokes' law.Rate this question:
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- 14.
Vacuum treatment (generally called vacuum degassing) is a commonly used steelmaking process, used for removing ____________ from the steel.
- A.
All impurities
- B.
Dissolved gases
- C.
Sulphur
- D.
Phosphorus
Correct Answer
B. Dissolved gasesExplanation
Vacuum treatment, also known as vacuum degassing, is a steelmaking process that is used to eliminate dissolved gases from the steel. This process helps to improve the quality and purity of the steel by removing impurities in the form of gases that may be present in the steel. By creating a vacuum environment, the dissolved gases are effectively removed, resulting in a cleaner and higher-quality steel product.Rate this question:
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- 15.
Flow from the tundish to the mould is uncontrolled.
- A.
True
- B.
False
Correct Answer
B. FalseExplanation
The statement "Flow from the tundish to the mould is uncontrolled" is false. This means that the flow from the tundish to the mould is actually controlled. The tundish is a container that holds the molten metal before it is poured into the mould. In a controlled flow, the molten metal is regulated and directed into the mould in a precise manner to ensure proper filling and solidification of the desired shape.Rate this question:
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- 16.
Direct strip casting minimises the need for substantial secondary processing.
- A.
True
- B.
False
Correct Answer
B. FalseExplanation
Direct strip casting does not minimize the need for substantial secondary processing. In fact, direct strip casting is a continuous casting process that produces thin strips of metal directly from the molten metal, but it still requires secondary processing such as heat treatment, rolling, and surface treatment to achieve the desired properties and dimensions. Therefore, the statement is false.Rate this question:
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- 17.
Carbon is a major impurity in Blast Furnace metal. Explain how blowing air through the molten metal helps to remove the carbon.
- 18.
Between the ladle and the water cooled mould is a tundish. This acts as a kind of reservoir for the molten metal. Why do you think this casting reservoir of liquid metal is held in the tundish?
- 19.
Replacing ingot casting by continuous casting of steel has: (a) reduced energy consumption (b) increased productivity in the steel industry. Explain why continuous casting has benefited the industry in these ways.
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