Aircraft Metals Technology Journeyman
(113).webp "Aircraft Metals Technology Journeyman - Quiz")
Volumn 1, first 100 questions
Questions and Answers
- 1.
Physical properties in metals are the properties that are
- A.
Changed by either heat treatment or cold working
- B.
Not changed by heat treatment or cold working
- C.
Changed by cold working only
- D.
Changed by heat treating only
Correct Answer
B. Not changed by heat treatment or cold workingExplanation
Physical properties in metals are not changed by heat treatment or cold working. Heat treatment involves heating and cooling the metal to alter its microstructure and improve its mechanical properties, such as hardness and strength. Cold working, on the other hand, involves deforming the metal at room temperature to increase its strength and hardness. However, these processes do not change the inherent physical properties of the metal, such as its density, melting point, electrical conductivity, and thermal conductivity. These properties remain constant regardless of heat treatment or cold working.Rate this question:
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- 2.
If a metal has a composition of 43% Fe, 1 % C, and 0.2% Ni, what type of metal is it?
- A.
Ferrous
- B.
Nonferrous
- C.
Nickel alloy
- D.
Titanium alloy
Correct Answer
A. FerrousExplanation
The metal with a composition of 43% Fe, 1% C, and 0.2% Ni is considered ferrous. This is because "ferrous" refers to metals that contain iron (Fe), and in this case, the metal has a significant amount of iron in its composition (43%). The presence of carbon (C) and nickel (Ni) does not change the fact that it is a ferrous metal.Rate this question:
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- 3.
If a metal has a composition of 15% Cr, 1% C, 0.21% Fe and 20% Ni, what type of metal is it?
- A.
Ferrous
- B.
Nonferrous
- C.
Titanium alloy
- D.
Aluminum alloy
Correct Answer
B. NonferrousExplanation
The metal in question has a composition that includes chromium (Cr), carbon (C), iron (Fe), and nickel (Ni), but does not contain any significant amount of iron. Ferrous metals are those that contain iron, while nonferrous metals are those that do not. Therefore, based on the given composition, the metal in question is nonferrous.Rate this question:
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- 4.
The difference between cast iron and cast steel is that
- A.
Cast iron contains more than 2% C
- B.
Cast steel contains more than 2% C
- C.
Cast steel has more hardening properties
- D.
Cast iron is more malleable
Correct Answer
A. Cast iron contains more than 2% CExplanation
Cast iron contains more than 2% carbon (C), which is what differentiates it from cast steel. Cast steel, on the other hand, may also contain carbon, but it does not necessarily have to contain more than 2% carbon. This difference in carbon content affects the properties of the materials. Cast iron is known for its high carbon content, which makes it brittle and less malleable compared to cast steel. Cast steel, on the other hand, may have more hardening properties due to its carbon content, but it is generally more malleable than cast iron.Rate this question:
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- 5.
The mechanical properties of a metal are determined by the
- A.
Grain structure
- B.
Alloying elements
- C.
Chemical analysis
- D.
Chemical compound
Correct Answer
A. Grain structureExplanation
The mechanical properties of a metal are determined by its grain structure. The grain structure refers to the arrangement of individual grains or crystals within the metal. The size, shape, and orientation of these grains can affect various mechanical properties such as strength, ductility, and toughness. For example, metals with a finer grain structure tend to be stronger and more resistant to deformation, while those with a larger grain structure may exhibit lower strength and increased susceptibility to fracture. Therefore, understanding and controlling the grain structure is crucial in designing and manufacturing metals with desired mechanical properties.Rate this question:
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- 6.
At room temperature, cementite grain structure
- A.
Contains a carbon content below .80%
- B.
Contains alternating layersof Fe and Fe3C
- C.
Is a mechanical mixture
- D.
Has no iron carbides
Correct Answer
C. Is a mechanical mixtureExplanation
The correct answer is "is a mechanical mixture". This means that at room temperature, the cementite grain structure is made up of a combination of different materials that are physically mixed together, rather than chemically bonded. This suggests that the structure is not a pure substance, but rather a mixture of different components.Rate this question:
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- 7.
When the elements of a metal are absorbed into each other, and the individual components cannot be seen, you have a
- A.
Chemical compound
- B.
Mechanical mixture
- C.
Solid solution
- D.
Pure metal
Correct Answer
C. Solid solutionExplanation
A solid solution is formed when the elements of a metal are absorbed into each other, resulting in a homogeneous mixture where the individual components cannot be distinguished. In a solid solution, the atoms of the different elements are evenly distributed throughout the material, creating a single phase. This is different from a mechanical mixture, where the components can be seen and are not uniformly distributed. A chemical compound refers to a substance formed by the chemical combination of different elements, while a pure metal refers to a material composed solely of one type of metal.Rate this question:
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- 8.
A metal's resistance to a high number of cyclic loads is known as
- A.
Compressive strength
- B.
Tensile strength
- C.
Fatigued strength
- D.
Shear strength
Correct Answer
C. Fatigued strengthExplanation
Fatigued strength refers to a metal's ability to withstand repeated cyclic loads without failure. It is a measure of the material's resistance to fatigue, which occurs when a metal is subjected to alternating stress over time. Fatigue failure can lead to cracks or fractures in the metal, making it important for materials to have a high fatigued strength to ensure durability and reliability under cyclic loading conditions. Compressive strength, tensile strength, and shear strength, on the other hand, refer to a metal's ability to withstand specific types of loads, but not necessarily cyclic ones.Rate this question:
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- 9.
What must be done to molten metal to form a cast product?
- A.
Pour it into a mold
- B.
Solution treat it
- C.
Cold work it
- D.
Anneal it
Correct Answer
A. Pour it into a moldExplanation
To form a cast product, molten metal needs to be poured into a mold. This process allows the molten metal to take the shape of the mold and solidify into the desired product. Pouring the molten metal into a mold ensures that it cools and solidifies in the desired form, resulting in a cast product.Rate this question:
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- 10.
Metal products shaped by force while in the solid state are clasified as
- A.
Machined
- B.
Wrought
- C.
Molded
- D.
Cast
Correct Answer
D. CastExplanation
Metal products shaped by force while in the solid state are classified as cast. This refers to the process of casting, where molten metal is poured into a mold and allowed to solidify. The solidified metal takes the shape of the mold and forms the desired product. Casting is commonly used to create complex shapes and is suitable for both small and large-scale production. It is different from machining, which involves removing material from a solid block, and from molding, which typically involves shaping materials in a semi-solid or liquid state. Wrought refers to metal that has been worked or shaped by hammering or rolling when it is in a solid state.Rate this question:
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- 11.
Metal that is worked after casting is considered
- A.
Machined
- B.
Wrought
- C.
Molded
- D.
Welded
Correct Answer
B. WroughtExplanation
The term "wrought" refers to metal that has been shaped or formed by hammering, rolling, or other mechanical processes after it has been cast. This process of working the metal after casting helps to improve its strength, durability, and overall quality. Therefore, "wrought" is the correct term to describe metal that has been worked after casting.Rate this question:
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- 12.
The process of pulling heated metal through a series of dies to produce a desired shape is known as
- A.
Rolling
- B.
Forging
- C.
Piercing
- D.
Drawing
Correct Answer
D. DrawingExplanation
Drawing is the correct answer because it refers to the process of pulling heated metal through a series of dies to produce a desired shape. This process is commonly used in the manufacturing industry to create long, thin objects such as wires or tubes. Rolling involves passing metal between two rollers to reduce its thickness, forging involves shaping metal by applying force, and piercing involves creating holes in metal by removing material.Rate this question:
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- 13.
What test involves the application of a slowly applied load along a sample's axis?
- A.
Shear
- B.
Static
- C.
Tensile
- D.
Elastic
Correct Answer
C. TensileExplanation
The test that involves the application of a slowly applied load along a sample's axis is called a tensile test. In this test, a sample is subjected to a gradually increasing load until it reaches its breaking point. The purpose of the test is to determine the strength and elasticity of the material being tested. By applying a load in tension, the test helps to measure the sample's ability to withstand stretching or pulling forces without breaking.Rate this question:
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- 14.
What is the weight of the minor load when testing for hardness using a Rockwell tester?
- A.
5 kg.
- B.
10 kg.
- C.
60 kg.
- D.
150 kg.
Correct Answer
B. 10 kg.Explanation
The weight of the minor load when testing for hardness using a Rockwell tester is 10 kg. This weight is used to initially penetrate the surface of the material being tested.Rate this question:
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- 15.
When a Rockwell tester is used for hardness testing, lack of surface uniformity results in
- A.
Soft spots
- B.
Hard spots
- C.
Errouneous readings
- D.
Errouneous minor load settings
Correct Answer
C. Errouneous readingsExplanation
When a Rockwell tester is used for hardness testing and there is a lack of surface uniformity, it can result in erroneous readings. This means that the hardness measurements obtained from the tester may not accurately reflect the true hardness of the material being tested. The lack of surface uniformity can cause variations in the depth of indentation made by the indenter, leading to inconsistent readings.Rate this question:
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- 16.
What scale is used on a Rockwell hardness tester for testing metals of unknown hardness?
- A.
A.
- B.
B.
- C.
C.
- D.
E.
Correct Answer
C. C.Explanation
The Rockwell hardness tester uses the C scale to test metals of unknown hardness. This scale is commonly used for softer metals such as aluminum, copper, and brass. The C scale measures the depth of penetration of a diamond cone or steel ball into the material, providing a hardness value that can be compared to a standard scale. This allows for accurate and consistent testing of metals to determine their hardness properties.Rate this question:
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- 17.
If you notice that the Brale penetrator is chipped, you should
- A.
File it
- B.
Hone it
- C.
Burnish it
- D.
Replace it
Correct Answer
D. Replace itExplanation
If the Brale penetrator is chipped, it is necessary to replace it. A chipped penetrator can affect the accuracy and reliability of measurements taken with it. Using a chipped penetrator can lead to inaccurate results and potentially damage the surface being tested. Therefore, it is important to replace the chipped penetrator to ensure accurate and reliable measurements.Rate this question:
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- 18.
What type of penetrator may you have if you get consistantly low readings with the Rockwell tester?
- A.
Flattened Brale
- B.
Chipped Brale
- C.
Flattened ball
- D.
Chipped ball
Correct Answer
B. Chipped BraleExplanation
If you consistently get low readings with the Rockwell tester, it suggests that the penetrator being used is not sharp enough to properly indent the material being tested. A chipped Brale penetrator would have a damaged tip, resulting in a less effective indentation and therefore lower readings.Rate this question:
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- 19.
The main difference between the SAE and AISI coding system is
- A.
AISI prefix identifies the chemical composition only
- B.
SAE prefix identifies the physical composition only
- C.
AISI prefix indicates the manufacturing process
- D.
SAE prefix indicates the manufacturing process
Correct Answer
C. AISI prefix indicates the manufacturing processExplanation
The given answer is incorrect. The main difference between the SAE (Society of Automotive Engineers) and AISI (American Iron and Steel Institute) coding systems is that the AISI prefix identifies the chemical composition of the material, while the SAE prefix identifies the physical composition or properties of the material. The AISI coding system is primarily used for steel and iron alloys, while the SAE coding system is used for a wider range of materials including metals, plastics, and rubber.Rate this question:
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- 20.
What metal identifictaion system uses a letter designator to seperate metals into 18 different family groupings?
- A.
AISI
- B.
JAN specifications
- C.
Federal specification numerics code
- D.
UNS
Correct Answer
D. UNSExplanation
UNS (Unified Numbering System) is a metal identification system that uses a letter designator to separate metals into 18 different family groupings. It provides a standardized method for identifying and classifying various types of metals based on their chemical composition and properties. This system is widely used in the metal industry to ensure consistency and accuracy in metal identification and classification.Rate this question:
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- 21.
When classifying heat treating furnaces, one variable is the
- A.
Air condition
- B.
Furnace load
- C.
Type of pyrometer
- D.
Type of thermocouple
Correct Answer
A. Air conditionExplanation
The variable that is being referred to when classifying heat treating furnaces is the air condition. This means that the classification of these furnaces depends on the specific air conditions that are used in the process of heat treatment. The air condition plays a crucial role in determining the temperature and atmosphere within the furnace, which in turn affects the quality and properties of the heat-treated material.Rate this question:
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- 22.
Circulating air furnaces are limited to operations that require
- A.
Carburizing atmospheres
- B.
Reactive atmospheres
- C.
High temperatures
- D.
Low temperatures
Correct Answer
D. Low temperaturesExplanation
Circulating air furnaces are designed specifically for operations that require low temperatures. These furnaces are capable of circulating cool air throughout the system, allowing for efficient cooling and maintaining a controlled low temperature environment. They are not suitable for operations that require high temperatures, carburizing atmospheres, or reactive atmospheres.Rate this question:
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- 23.
When heat treating, using a reactive atmosphere results in chemical
- A.
Inertness
- B.
Blending
- C.
Reduction
- D.
Movement
Correct Answer
B. BlendingExplanation
When heat treating, using a reactive atmosphere can result in blending. This means that the reactive atmosphere combines with the material being treated, causing a chemical reaction. This blending process can lead to desired changes in the material's properties, such as improved hardness or increased strength. Reactive atmospheres are often used in heat treatment processes to achieve specific outcomes by altering the chemical composition of the material.Rate this question:
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- 24.
What is the primary benefit of an oxidizing reactive atmosphere?
- A.
Reduces reactivity
- B.
Increases inertness
- C.
Aids in hardening
- D.
Lowers cost
Correct Answer
D. Lowers costExplanation
An oxidizing reactive atmosphere can lower cost because it reduces the reactivity of materials, which can prevent unwanted reactions and reduce the amount of waste or byproducts produced. This can lead to more efficient and cost-effective processes, as well as lower maintenance and cleanup costs. Additionally, by decreasing reactivity, an oxidizing reactive atmosphere can also increase the inertness of materials, making them more stable and less prone to degradation or corrosion. This can further contribute to cost savings by extending the lifespan of materials and reducing the need for replacements or repairs.Rate this question:
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- 25.
Would you use a nitrogen atmosphere for hardening stainless steel? why?
- A.
Yes, aids in chemical properties
- B.
Yes, to case-harden high carbon steels
- C.
No, may result in surface blistering
- D.
No, produces undesirable properties in metals
Correct Answer
D. No, produces undesirable properties in metalsExplanation
Using a nitrogen atmosphere for hardening stainless steel would not be recommended because it produces undesirable properties in metals. Nitrogen can cause surface blistering, which is not desirable in the hardening process. Additionally, nitrogen may introduce impurities or alter the chemical composition of the steel, leading to negative effects on its overall properties. Therefore, it is best to avoid using a nitrogen atmosphere for hardening stainless steel.Rate this question:
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- 26.
The choice of heating element depends on the furnace
- A.
Function and atmosphere
- B.
load and atmosphere
- C.
Load and function
- D.
Size and function
Correct Answer
A. Function and atmosphereExplanation
The choice of heating element depends on the function and atmosphere of the furnace. The function refers to the specific purpose or process that the furnace is designed for, such as melting, annealing, or heat treating. Different functions require different heating elements with varying temperature capabilities and heat distribution properties. The atmosphere refers to the gas or environment inside the furnace, which can be inert, oxidizing, or reducing. The choice of heating element also depends on the compatibility with the atmosphere to ensure optimal performance and longevity.Rate this question:
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- 27.
Which furnace component protects the heating elements from damamge and serves as the floor to the furnace?
- A.
Baffles
- B.
Grid rack
- C.
Insulation
- D.
Hearth plate
Correct Answer
D. Hearth plateExplanation
The hearth plate is the correct answer because it serves as the floor to the furnace and protects the heating elements from damage. It acts as a barrier between the heating elements and the rest of the furnace, preventing any direct contact and potential damage. The hearth plate also helps to distribute heat evenly throughout the furnace, ensuring efficient heating.Rate this question:
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- 28.
To maintain an atmosphere around the thermocouple equal tot hatt of theair at room temperature, heat-treating furnaces require
- A.
Pyrometers
- B.
Extension leads
- C.
Protective tubes
- D.
Inert atmospheres
Correct Answer
C. Protective tubesExplanation
Heat-treating furnaces require protective tubes to maintain an atmosphere around the thermocouple equal to that of the air at room temperature. Protective tubes act as a barrier, preventing the thermocouple from coming into direct contact with the high temperatures and corrosive gases inside the furnace. This helps to protect the thermocouple from damage and ensures accurate temperature measurements. Without protective tubes, the thermocouple would be exposed to the harsh conditions inside the furnace, leading to inaccurate readings and potential failure of the thermocouple.Rate this question:
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- 29.
What type is the most accurate pyrometer used today on heat-treating furnaces?
- A.
Millivoltmeter
- B.
Potentiometer
- C.
Thermocouple
- D.
Electronic
Correct Answer
C. ThermocoupleExplanation
A thermocouple is the most accurate pyrometer used today on heat-treating furnaces. A thermocouple is a device that consists of two different metals joined together at one end. When there is a temperature difference between the two ends, it creates a voltage that can be measured. This voltage is proportional to the temperature, allowing the thermocouple to accurately measure the heat in the furnace. Other options like a millivoltmeter, potentiometer, or electronic devices may have their applications, but a thermocouple is specifically designed for accurate temperature measurement in high-temperature environments like heat-treating furnaces.Rate this question:
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- 30.
An oxidized thermocouple results in
- A.
Contaminated oven atmospheres
- B.
Incorrect temperature readings
- C.
Excessive heat loss
- D.
Stress on the leads
Correct Answer
B. Incorrect temperature readingsExplanation
When a thermocouple is oxidized, it means that its surface has reacted with oxygen in the air, forming a layer of oxide. This oxide layer can interfere with the accurate measurement of temperature, causing incorrect temperature readings. The oxide layer acts as an insulator, reducing the thermocouple's ability to accurately sense and transmit temperature changes. Therefore, an oxidized thermocouple can lead to inaccurate temperature readings.Rate this question:
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- 31.
The amount of hardness or softness you can achieve for carbon and low alloy steels is dictated by the
- A.
Soaking time
- B.
Carbon content
- C.
Quench medium
- D.
Treatment process
Correct Answer
B. Carbon contentExplanation
The amount of hardness or softness that can be achieved for carbon and low alloy steels is determined by the carbon content. Carbon is the main alloying element in these steels and it influences their mechanical properties, including hardness. Higher carbon content generally leads to higher hardness, while lower carbon content results in lower hardness. Therefore, the carbon content plays a crucial role in determining the hardness or softness of these steels.Rate this question:
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- 32.
When three atoms of iron and one atom of carbon chemically unite, the resulting compound is known as
- A.
Fe3C
- B.
FeE3
- C.
Fe3
- D.
FC3
Correct Answer
A. Fe3CExplanation
When three atoms of iron and one atom of carbon chemically unite, they form a compound known as Fe3C. This compound is also called iron carbide or cementite. It is a hard and brittle compound that is commonly found in steel alloys. The Fe3C compound has a crystal structure that consists of iron atoms surrounded by carbon atoms. It is an important component in the microstructure of steel and contributes to its strength and hardness.Rate this question:
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- 33.
To prevent excessive grain growth when heat treating carbon and alloy steel, you must soak
- A.
Only long enough at the critical point
- B.
Only long enough to ensure uniform heating
- C.
Slightly less than required to ensure uniform heating
- D.
Slightly longer than required to ensure uniform heating
Correct Answer
B. Only long enough to ensure uniform heatingExplanation
To prevent excessive grain growth when heat treating carbon and alloy steel, it is necessary to soak the material only long enough to ensure uniform heating. This means that the material should be heated for the minimum amount of time required to reach a uniform temperature throughout. If the soaking time is too short, the material may not be heated evenly, leading to uneven grain growth. On the other hand, if the soaking time is too long, there is a risk of excessive grain growth, which can negatively impact the mechanical properties of the steel. Therefore, the correct approach is to soak the material only for the required duration to achieve uniform heating.Rate this question:
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- 34.
To prevent cracking when cold working metal
- A.
Slightly stress relieve or partially anneal it
- B.
Ensureit is at maximum depth hardness
- C.
Remove impurities from the grains
- D.
Temper it to remove strain
Correct Answer
A. Slightly stress relieve or partially anneal itExplanation
To prevent cracking when cold working metal, it is necessary to slightly stress relieve or partially anneal it. This process helps to reduce the internal stresses that build up during cold working, which can lead to cracking or failure of the metal. By applying controlled heat treatment, the metal is allowed to relax and redistribute the internal stresses, making it less prone to cracking and improving its overall strength and ductility.Rate this question:
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- 35.
What is an adverse effect of hardening steels?
- A.
Lowered corrosion resistance
- B.
Excessive grain growth
- C.
Malleabliity increases
- D.
Brittleness increases
Correct Answer
D. Brittleness increasesExplanation
Hardening steels can lead to an increase in brittleness. This occurs because the hardening process involves heating the steel to high temperatures and then rapidly cooling it, which can cause the formation of hard but brittle martensite. This increase in brittleness makes the steel more prone to fractures and less able to withstand impacts or deformations without breaking.Rate this question:
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- 36.
Metal parts with uneven cross sections require
- A.
Slow quenching
- B.
Quick quenching
- C.
Faster heating rates
- D.
Slower heating rates
Correct Answer
D. Slower heating ratesExplanation
Metal parts with uneven cross sections require slower heating rates because uneven cross sections can cause thermal stresses during the heating process. Slower heating rates allow for a more uniform temperature distribution throughout the part, reducing the likelihood of thermal stresses and potential deformation or cracking. By heating the part slowly, the temperature can gradually equalize, minimizing the temperature gradients and ensuring a more controlled and uniform heating process. This helps to maintain the structural integrity of the metal part and prevent any undesirable effects that may occur due to rapid or uneven heating.Rate this question:
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- 37.
When a steel part of unequal cross section is heat treated, the soaking period is determined by the
- A.
Mechanical properties of the part
- B.
Physical properties of the part
- C.
Heaviest cross section
- D.
Lightest cross section
Correct Answer
C. Heaviest cross sectionExplanation
The soaking period during heat treatment of a steel part of unequal cross section is determined by the heaviest cross section. This is because the heaviest cross section takes the longest time to reach the desired temperature throughout its entire thickness. Soaking is necessary to ensure that the entire part reaches a uniform temperature, allowing for proper transformation and achieving the desired mechanical properties.Rate this question:
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- 38.
Decalescence occurs when heated steel
- A.
Transforms at 1450^F
- B.
Transforms at the Ar1 point
- C.
Absorbs heat without a rise in temperature
- D.
Dissipates heat without a decrease in temperature
Correct Answer
C. Absorbs heat without a rise in temperatureExplanation
Decalescence refers to a phenomenon in which heated steel absorbs heat without a corresponding increase in temperature. This means that even though heat is being transferred to the steel, its temperature remains constant. This can occur when the steel undergoes a phase transformation at a specific temperature, such as the Ar1 point mentioned in the options. During this transformation, the absorbed heat is utilized to change the internal structure of the steel rather than raising its temperature. Therefore, the correct answer is that decalescence occurs when heated steel absorbs heat without a rise in temperature.Rate this question:
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- 39.
For a given type of steel, the time that a material remains in decalescence is based on the
- A.
Transformation temperature
- B.
Mechanical properties
- C.
Physical properties
- D.
Metal's mass
Correct Answer
D. Metal's massExplanation
The time that a material remains in decalescence, which is the period during which the material is cooling and undergoing a phase transformation, is based on the metal's mass. The larger the mass of the metal, the longer it takes for the material to cool down and complete the phase transformation. Therefore, the mass of the metal directly affects the duration of decalescence.Rate this question:
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- 40.
During the heat treating process, when the part has a sudden liberation of heat without a drop in temperature, it is called
- A.
Recalescence
- B.
Decalescence
- C.
Amalgamation point
- D.
Transformation point
Correct Answer
A. RecalescenceExplanation
Recalescence refers to the phenomenon in the heat treating process where there is a sudden liberation of heat without a drop in temperature. This can occur when the material undergoes a phase transformation, such as during the solidification of a molten metal or the crystallization of an alloy. The sudden release of heat during recalescence can have important implications for the heat treatment process, as it can affect the microstructure and properties of the material being treated.Rate this question:
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- 41.
During the heat treating of low alloy steel, upon slow cooling to the A1 point, transformation occurs
- A.
At slightly higher temperatures than when heating
- B.
At slightly lower temperatures than when heating
- C.
Upon austenization
- D.
At 1333 degrees F
Correct Answer
B. At slightly lower temperatures than when heatingExplanation
During the heat treating of low alloy steel, the transformation occurs at slightly lower temperatures than when heating. This is because during the slow cooling process, the steel undergoes a phase change from austenite to ferrite and/or pearlite. This transformation occurs at a lower temperature compared to when the steel is being heated, where the austenite phase is formed.Rate this question:
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- 42.
During the heat treating of low alloy steel, upon fast cooling to tthe Ar1 point, transformation occurs
- A.
At 1333 degrees F
- B.
Upon austenization
- C.
At temperatures far below the heating temperatures
- D.
At temperatures far above the heating temperatures
Correct Answer
C. At temperatures far below the heating temperaturesExplanation
During the heat treating of low alloy steel, transformation occurs at temperatures far below the heating temperatures. This means that the transformation takes place at a lower temperature than the temperature at which the steel was heated. This is a common phenomenon in heat treating processes, where the steel is heated to a high temperature to achieve certain desired properties, and then cooled rapidly to induce the transformation at a lower temperature.Rate this question:
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- 43.
When heat treating a part of uneven cross section, what is the quenching procedure?
- A.
Immerse both sections simultaneously.
- B.
Immerse heavier section first
- C.
Immerse lighter section first
- D.
There is no set procedure
Correct Answer
B. Immerse heavier section firstExplanation
When heat treating a part of uneven cross section, it is important to immerse the heavier section first during the quenching procedure. This is because the heavier section will retain heat for a longer period of time, and by immersing it first, it ensures that both sections cool down at a similar rate. If the lighter section is immersed first, it may cool down too quickly, causing uneven cooling and potentially leading to distortion or other issues in the part. By immersing the heavier section first, it allows for more uniform cooling and helps to prevent any potential problems.Rate this question:
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- 44.
When quenching a heat-treated part in a liquid medium, the purpose for agitation is to
- A.
Minimize warpage
- B.
Prevent hard spots
- C.
Cause steam pockets to form
- D.
Maintain cantact with the quenchant
Correct Answer
D. Maintain cantact with the quenchantExplanation
Agitation is necessary during the quenching process to maintain contact between the part being quenched and the quenchant (liquid medium). This ensures that the heat is transferred evenly and efficiently from the part to the quenchant, allowing for a uniform cooling rate. By maintaining contact with the quenchant, the part is able to achieve the desired hardness and avoid the formation of hard spots or warpage. Additionally, agitation helps to prevent the formation of steam pockets, which could hinder the quenching process.Rate this question:
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- 45.
When quenching a heat-treated part in a liquid medium, stirring ahould be
- A.
Induced to prevent warpage
- B.
Minimized to prevent warpage
- C.
Induced to create steam pockets
- D.
Minimized to create steam pockets
Correct Answer
B. Minimized to prevent warpageExplanation
When quenching a heat-treated part in a liquid medium, minimizing stirring is necessary to prevent warpage. Stirring can cause uneven cooling, leading to internal stresses and distortion in the part. By minimizing stirring, the heat is evenly distributed, reducing the risk of warpage and ensuring the part maintains its desired shape and dimensions.Rate this question:
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- 46.
When annealing steel parts, the cooling rate depends on the
- A.
Internal stress of the part
- B.
Composition of the metal
- C.
Transformation point
- D.
Mass of the part
Correct Answer
B. Composition of the metalExplanation
The cooling rate during annealing steel parts depends on the composition of the metal. Different metals have different thermal properties, such as their specific heat capacity and thermal conductivity, which affect how quickly they can dissipate heat. Therefore, the composition of the metal determines how fast or slow the steel part will cool down during the annealing process.Rate this question:
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- 47.
Which type of steel has the highest normalizing temperature?
- A.
Eutectoid
- B.
Hypoeutectoid
- C.
Hypereutectoid
- D.
Hypersaturated
Correct Answer
C. HypereutectoidExplanation
The highest normalizing temperature is found in hypereutectoid steel. Hypereutectoid steel contains a higher percentage of carbon than the eutectoid and hypoeutectoid steels. Normalizing is a heat treatment process that involves heating the steel above its critical temperature and then cooling it in still air. This process helps to refine the grain structure and improve the mechanical properties of the steel. Since hypereutectoid steel has a higher carbon content, it requires a higher temperature to achieve the desired grain refinement and transformation.Rate this question:
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- 48.
What is required to achieve hardness in ferrous metals?
- A.
Soaking time must be based on the alloying element
- B.
The material must contain sufficeint carbon content
- C.
The material must be heated to slightly below Ac1
- D.
All elements must go into solid austenitic solution
Correct Answer
B. The material must contain sufficeint carbon contentExplanation
To achieve hardness in ferrous metals, it is necessary for the material to have sufficient carbon content. Carbon is a key element in the formation of different phases in steel, such as martensite, which contributes to hardness. The presence of carbon allows for the transformation of the material's microstructure during heat treatment, resulting in increased hardness. Without sufficient carbon content, the material will not be able to achieve the desired level of hardness.Rate this question:
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- 49.
As the percentage of carbon increases in steels, the hardening temperature
- A.
Increases
- B.
Decreases
- C.
Increases then stabilizes
- D.
Decreases then stabilizes
Correct Answer
B. DecreasesExplanation
As the percentage of carbon increases in steels, the hardening temperature decreases. This is because carbon is a strong carbide former and it increases the hardenability of steel. As the carbon content increases, the steel can achieve the desired hardness at lower temperatures, reducing the need for high heat treatment temperatures. However, after a certain point, increasing the carbon content further does not significantly affect the hardenability, and the hardening temperature stabilizes. Therefore, the correct answer is decreases.Rate this question:
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- 50.
To prevent the formation of pearlite when hardening carbon steel, cool it below 1000 degrees F in less than
- A.
1/4 second
- B.
1/2 second
- C.
1 second
- D.
2 seconds
Correct Answer
C. 1 secondExplanation
To prevent the formation of pearlite when hardening carbon steel, it is necessary to cool it rapidly. Cooling the steel below 1000 degrees F in less than 1 second ensures that there is not enough time for the pearlite structure to form. Pearlite is a mixture of ferrite and cementite that forms during slow cooling, and it can reduce the hardness and strength of the steel. By cooling the steel rapidly, the formation of pearlite is avoided, resulting in a harder and stronger material.Rate this question:
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Nov 09, 2023Quiz Edited by
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Mar 02, 2009Quiz Created by
A1cspyder
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