Science Exam: Ultimate Questions! Quiz

Tool and die steel is not a structural class of steel. It is a type of steel that is specifically designed for use in tooling and die making applications. It is known for its high hardness, wear resistance, and toughness, making it suitable for cutting, shaping, and forming materials. On the other hand, low carbon, stainless steel, and medium carbon steel are all structural classes of steel that are commonly used in various construction and engineering applications.

Galvanized iron refers to iron that has been coated with zinc. This coating helps to protect the iron from corrosion and rust, as zinc is a highly resistant metal. The process of galvanization involves immersing the iron in a bath of molten zinc, allowing the zinc to bond with the iron surface. This creates a durable and long-lasting protective layer that helps to extend the lifespan of the iron. Therefore, zinc is the correct answer in this case.

Tool and die steel is not a structural class of steel. It is a type of steel specifically designed for making tools and dies for manufacturing processes. Structural classes of steel, on the other hand, are used for constructing buildings, bridges, and other load-bearing structures. Low carbon steel, high chrome alloy steel, and high strength low alloy steel are examples of structural classes of steel that are commonly used in construction.

Rusting is the correct answer because it refers to the process of corrosion specifically for iron or iron-based alloys. When iron is exposed to oxygen and water, it undergoes a chemical reaction that forms iron oxide, commonly known as rust. This process weakens the iron and leads to the formation of a reddish-brown coating on the surface. Rusting is a common issue for iron objects and can cause structural damage if left untreated.

The correct answer is "Design= ultimate stress divided by factor of safety". This equation is derived from the given relationship between design stress and factor of safety. According to the equation, the design stress is obtained by dividing the ultimate stress by the factor of safety. This means that the design stress is determined by considering the ultimate stress and applying a safety factor to ensure the structural integrity and reliability of the design.

Poisson's ratio is a measure of the ratio of lateral strain to longitudinal strain in a material. It describes how a material deforms when subjected to an applied force. Lateral strain refers to the change in width or thickness of a material, while longitudinal strain refers to the change in length. The ratio between these two strains is known as Poisson's ratio and is a fundamental property of materials.

Poisson's ratio is a property of material that relates the lateral strain to the longitudinal strain. It is a measure of the ratio of the amount of transverse or lateral strain to the amount of longitudinal strain in a material. Poisson's ratio is important in determining the deformation behavior of materials under stress and is used in various engineering applications, such as in designing structures to withstand loads and in predicting material failure.

Mercury is a liquid metal because it has a low melting point of -38.83 degrees Celsius (-37.89 degrees Fahrenheit). This allows it to exist in a liquid state at room temperature. Lead, zinc, and aluminum, on the other hand, have higher melting points and are solid at room temperature.

Torsional strength refers to a metal's ability to resist forces that cause twisting or torsion. It is a measure of the metal's ability to withstand rotational forces without deforming or breaking. This characteristic is important in applications where the metal is subjected to twisting or rotational forces, such as in shafts, gears, or springs. Torsional strength is different from modulus of elasticity, which measures a material's ability to deform under an applied force, and twisting moment, which refers to the force that causes the twisting. Elasticity, on the other hand, is a general property of materials that describes their ability to return to their original shape after being deformed.

Ferrous metals contain a relatively large amount of carbon. Carbon is an essential element in ferrous metals as it provides strength and hardness to the metal. The presence of carbon allows ferrous metals to be easily hardened and tempered, making them suitable for various applications. Additionally, carbon also improves the metal's ability to withstand wear and tear, making it more durable. Therefore, the high carbon content in ferrous metals is crucial for their mechanical properties and overall performance.

Strain is the correct answer because it refers to the unit of deformation. When an object undergoes deformation due to the application of a force, strain measures the amount of deformation that occurs. It quantifies how much an object has stretched or compressed compared to its original size. Torsion, stress, and shear are not units of deformation but rather describe different types or causes of deformation.

The structural class of steel refers to the different types of steel used in construction and engineering applications. High speed steel, low carbon, and high carbon are all examples of structural classes of steel. However, "tool and die" is not a structural class of steel. Tool and die steel is a specific type of steel used in the manufacturing of tools, dies, and molds, but it is not classified as a structural steel.

Poisson's ratio is the property of a material that relates the lateral strain to the longitudinal strain. It is a measure of the deformation that occurs perpendicular to an applied force. Poisson's ratio is defined as the negative ratio of the transverse strain to the axial strain. It is an important parameter in materials science and engineering as it helps to understand how a material will deform under different types of stress.

Cold working is a process that involves deforming the metal at room temperature, such as through rolling or hammering. This causes the metal to become stronger and harder, as the dislocations in the crystal structure of the metal are increased. Copper and its alloys can be hardened through cold working because they have a face-centered cubic crystal structure, which allows for easy dislocation movement. Patenting, case hardening, and soaking are not methods typically used to harden copper and its alloys.

Sulfur is harmful to ferrous metal in greater quantities because it can react with iron to form iron sulfide, which weakens the metal's structure and makes it more prone to corrosion. This reaction can lead to the formation of rust and ultimately degrade the metal's integrity. Therefore, an increased presence of sulfur can be detrimental to ferrous metals.

SAE 1030 is the correct answer because it is a commonly utilized and cheapest shaft material available in the market. It has a carbon content of 0.28-0.34% C, which falls within the given range.

The ultimate strength refers to the maximum stress that a material can withstand before it fails or breaks. It is determined by considering the maximum test load acting over the original area of the test specimen. This means that the ultimate strength is the highest stress intensity that the material can handle without experiencing permanent deformation or failure.

Strength refers to the ability of a material, such as metals, to withstand loads and forces without breaking down. It is a measure of the material's resistance to deformation or failure under applied stress. In other words, strength determines how much stress a material can handle before it reaches its breaking point. This property is crucial in various applications, such as construction, engineering, and manufacturing, where materials need to withstand heavy loads and forces without failure.

The process of hardening is different from the other three processes mentioned. Resistance welding, soldering, and brazing all involve joining or bonding materials together, while hardening is a heat treatment process used to increase the hardness and strength of a material. Therefore, hardening does not belong to the group of processes that involve joining or bonding materials.

Casting is the process of pouring molten metal into a mold to create a solid object. It involves melting and shaping the metal, but it does not involve joining separate pieces of metal together. Welding, soldering, and brazing, on the other hand, all involve joining separate pieces of metal together. Welding involves melting the edges of the metal pieces and fusing them together, soldering involves melting a filler metal to join the pieces, and brazing involves heating the metal pieces and using a filler metal with a lower melting point to join them.

Metals are conductive because the electrons in their outer energy levels are not tightly bound to the nuclei of their atoms. This allows the electrons to move freely within the metal, creating a flow of electric charge. This mobility of electrons is what makes metals good conductors of electricity.

Inertia is the property of matter that causes it to resist any change in its motion or state of rest. It is the tendency of an object to maintain its current state unless acted upon by an external force. This means that an object at rest will stay at rest, and an object in motion will continue moving at a constant velocity, unless a force is applied to change its state. Inertia is a fundamental concept in physics and is related to the mass of an object. The greater the mass, the greater the inertia.

Ductility is the property that characterizes a material's ability to be drawn into wire. This means that the material can be stretched and deformed without breaking, allowing it to be formed into thin wires. Thermal conductivity refers to a material's ability to conduct heat, tensile strength refers to its ability to withstand tension, and endurance limit refers to the maximum stress level that a material can endure without breaking.

Strength is the correct answer because it refers to the capacity of a metal to withstand load without breaking. It is a measure of the material's ability to resist deformation or failure under applied forces or loads. Strength is an important property in engineering and structural design, as it ensures the structural integrity and safety of the metal component. Stress, elasticity, and strain are related concepts, but they do not specifically address the metal's ability to withstand load without breaking.

The maximum stress reached during a tension test is referred to as the tensile strength. Tensile strength is a measure of the material's ability to withstand pulling forces without breaking. It represents the maximum amount of stress the material can handle before it fails under tension. This property is important in determining the suitability of a material for applications where it will be subjected to stretching or pulling forces.

The correct answer is Foundry area. The foundry area in a machine shop is where metal is melted and shaped into a new form. It is where the process of casting takes place, which involves pouring molten metal into a mold to create a specific shape. This area is specifically dedicated to the melting and casting of metals, making it the appropriate choice for the given question.

Rocking strength is not a strength property of metals. Tensile strength refers to the ability of a material to withstand tension or stretching forces. Fatigue strength is the ability of a material to resist damage under cyclic loading. Torsional strength is the ability of a material to resist twisting or torsion forces. However, rocking strength is not a commonly recognized strength property of metals.

Bronze is an alloy that is primarily composed of copper. Copper is the major component of bronze casting because it provides the base metal for the alloy. Other elements like zinc and manganese are often added to bronze to enhance its properties, such as improving its strength or corrosion resistance. However, copper remains the main component in bronze casting.

Killed steel is a type of steel that has been deoxidized with the addition of silicon. Silicon is added to the steel during the manufacturing process to remove any oxygen present, which helps improve the steel's properties. This process also helps to reduce the formation of undesirable impurities such as sulfur and phosphorus. Therefore, silicon is closely associated with killed steel.

Cold working of steel plates involves subjecting the metal to mechanical stress at temperatures below its recrystallization point. This process causes the grains of the metal to deform and align, resulting in an increase in hardness. Therefore, the correct answer is harder.

Lead iron is not a kind of cast iron. Cast iron is typically categorized into different types based on its composition and properties. Gray iron, white iron, and malleable iron are all types of cast iron that are commonly used in various industries. However, lead iron is not a recognized type of cast iron. It is possible that the term "lead iron" is a mistake or a misnomer, as lead is not typically used as an alloying element in the production of cast iron.

Compressive strength refers to the ability of a material or metal to resist being crushed. This means that it can withstand external forces or loads that are applied in a direction towards its center, without undergoing significant deformation or failure. Fatigue strength, bending strength, and torsional strength are all different types of strength properties that measure a material's resistance to specific types of loads or forces, but they do not specifically measure its ability to resist being crushed. Therefore, compressive strength is the correct answer in this case.

All of these options (manganese, silicon, and aluminum) are good deoxidizers in steel melting. Deoxidizers are added to remove oxygen from the steel, preventing the formation of unwanted oxides. Manganese reacts with oxygen to form manganese oxide, silicon reacts to form silicon oxide, and aluminum reacts to form aluminum oxide. By adding these deoxidizers, the steel can be purified and have improved mechanical properties. Therefore, all of these options are correct.

All of these elements, columbium, titanium, and aluminum, are good stabilizers in stainless steel. These elements help to prevent the formation of harmful carbides during the heating and cooling processes involved in stainless steel production. By stabilizing the steel, they improve its corrosion resistance and mechanical properties, making it more durable and suitable for various applications.

Corrosion refers to the gradual chemical reaction that occurs when a metal reacts with other substances, resulting in the conversion of the metal into an oxide or other compounds. This process is commonly observed in metals exposed to moisture or certain chemicals, leading to the formation of rust or other corrosion products.

Galvanized steel plate is coated with zinc. This coating provides protection against corrosion and extends the lifespan of the steel plate. Zinc is commonly used for galvanization due to its excellent corrosion resistance properties. It forms a protective layer on the steel surface, preventing the underlying metal from coming into contact with moisture and oxygen, which are key factors in causing rust. Zinc-coated steel plates are widely used in various industries, including construction, automotive, and manufacturing, due to their durability and resistance to corrosion.

The correct answer is "Modulus of elasticity." The modulus of elasticity is a measure of a material's stiffness and is defined as the ratio of stress to strain within the elastic region of a material's stress-strain curve. It represents how much a material will deform under a given amount of stress. The other options, such as the gage method and tensile strength, do not directly relate to the ratio of stress to strain below the proportional limit.

Hardening is the only process in the group that does not involve joining or bonding of materials. Brazing, soldering, and resistance welding all involve joining or bonding materials together using heat or pressure. Hardening, on the other hand, is a process used to increase the strength or durability of a material by heat treatment or other methods. Therefore, hardening does not belong to the group of processes that involve joining or bonding materials.

A shaper machine is capable of flattening surfaces on a horizontal, vertical, or angular plane. It uses a cutting tool that moves in a reciprocating motion to remove material and create a flat surface. This machine is commonly used for shaping and finishing metal or wood surfaces. A drilling machine is used for creating holes, a power saw is used for cutting materials, and a lathe machine is used for shaping and turning cylindrical objects. Therefore, the shaper machine is the correct answer for the given question.

Ferrous metals contain a relatively large amount of carbon. Carbon is a common alloying element in ferrous metals, such as steel, which enhances their mechanical properties. The addition of carbon increases the hardness, strength, and wear resistance of ferrous metals, making them suitable for various applications in industries like construction, automotive, and manufacturing. Carbon also improves the machinability and heat-treatability of ferrous metals, allowing for easier shaping and customization of the material's properties.

Deformation refers to the changes in shape or geometry of a body caused by the application of a force. Strain is a measure of this deformation, indicating the extent to which the body has been distorted or stretched. It is a measure of the relative change in shape or size of the body due to the applied force. Therefore, strain is the correct term to describe the changes in shape or geometry of a body caused by the action of a force.

The given options are all associated with the grade of steel except SAE 74XX. The other options, SAE 43XX, SAE 13 XX, and SAE 10XX, are all examples of steel grade designations. The SAE 74XX is not a recognized steel grade designation, making it the correct answer.

A minimum chromium content of 8% is required for a high corrosion resistant stainless steel. Chromium is a key element in stainless steel that provides corrosion resistance by forming a passive oxide layer on the surface of the steel. The higher the chromium content, the better the corrosion resistance. Therefore, a minimum of 8% chromium ensures that the stainless steel has a high level of corrosion resistance.

The correct answer states that brass is composed of copper and zinc, while bronze is composed of copper and tin. This explanation accurately describes the main difference between brass and bronze, which is the composition of the two alloys. Brass is a combination of copper and zinc, while bronze is a combination of copper and tin.

Killed steel is a type of steel that has been deoxidized using elements such as silicon, manganese, phosphorus, or sulfur. These elements help to remove oxygen and other impurities from the steel during the manufacturing process, resulting in a more uniform and refined steel product. Therefore, the correct answer is silicon, as it is one of the elements commonly used in the production of killed steel.

Babbit is a type of metal alloy that is commonly used as a bearing material in machinery. It has excellent lubricating properties, which means it can assist in the lubrication process or even act as a lubricant itself. Babbit alloys typically consist of tin, copper, and antimony, which provide low friction and wear resistance. This makes babbit an ideal choice for applications where lubrication is crucial, such as in engine bearings, bushings, and other rotating parts.

Stainless steel is obtained principally by the use of chromium as an alloying element. Chromium is added to steel in varying amounts to enhance its corrosion resistance and durability. It forms a thin, protective oxide layer on the surface of the steel, preventing it from rusting or staining. Additionally, chromium also improves the steel's heat resistance, strength, and hardness. Nickel is sometimes added to stainless steel as well, but chromium is the primary alloying element responsible for its stainless properties. Carbon and tungsten are not typically used as alloying elements in stainless steel production.

Grease is considered a semi-solid lubricant because it is a mixture of oil and a thickening agent, usually a soap or a metallic soap. This combination creates a semi-solid consistency that allows the grease to adhere to surfaces and provide lubrication. Grease is commonly used in applications where high viscosity and resistance to water and contaminants are required. Therefore, it can be categorized as a semi-solid lubricant along with lube oil and graphite.

Plasticity refers to the property of a material, specifically metal in this case, to undergo significant deformation without rupturing or breaking. It is the ability of a metal to change shape permanently under applied stress without losing its integrity. This property is highly desirable in engineering and manufacturing processes as it allows for the shaping and forming of metals into various desired shapes and structures. Ductility and malleability are related properties but specifically refer to the ability of a metal to be stretched or hammered into thin sheets respectively. Therefore, plasticity encompasses both ductility and malleability, making "plasticity" the correct answer.

The melting point refers to the temperature at which a solid substance, such as an alloy, changes into a liquid state. Therefore, the correct answer is "Melting point" because it indicates the temperature at which the alloy will become liquid and flow.