Steel Making

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.

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.

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.

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.

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.

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.

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.

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.

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.

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.

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.

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.

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.

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.

Bismuth is not injected in deep cutting steels to improve machinability.

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.