Materials And Processes #1
- 1.
Aside from increasing the integrity and safety of manufactured pieces, nondestructive testing cuts costs by:
- A.
Increasing production rates
- B.
Reducing personnel
- C.
Eliminating poor stock prior to processing
- D.
All of the above
Correct Answer
C. Eliminating poor stock prior to processingExplanation
Nondestructive testing helps in identifying any defects or flaws in the stock before it goes through the processing stage. By eliminating poor stock prior to processing, the need for rework or scrap is reduced, resulting in cost savings. This ensures that only high-quality materials are used in the manufacturing process, leading to improved integrity and safety of the final products. Additionally, nondestructive testing does not damage or destroy the tested materials, allowing for increased production rates and reducing the need for additional personnel. Therefore, the correct answer is "eliminating poor stock prior to processing."Rate this question:
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- 2.
In order to evaluate a defect an inspector must have:
- A.
knowledge of the test
- B.
A knowledge of the material tested
- C.
A knowledge of the applicable codes
- D.
All of the above
Correct Answer
D. All of the aboveExplanation
To effectively evaluate a defect, an inspector must possess knowledge of the test being conducted, as this will determine the criteria for identifying and assessing defects. Additionally, a knowledge of the material being tested is essential, as different materials may have unique defect characteristics and requirements. Finally, a knowledge of the applicable codes is necessary to ensure that the evaluation is in compliance with industry standards and regulations. Therefore, the correct answer is "all of the above" as all three factors are crucial for an inspector to accurately evaluate a defect.Rate this question:
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- 3.
It may be said that specialists in non-destructive testing must:
- A.
Be aware of the capabilities of materials to sustain deformation without forming defects.
- B.
Be knowledgeable about the materials they inspect and the defects which can form in them.
- C.
Have an exhaustive knowledge of metallurgy.
- D.
All the above answers are correct.
Correct Answer
B. Be knowledgeable about the materials they inspect and the defects which can form in them.Explanation
Specialists in non-destructive testing need to be knowledgeable about the materials they inspect and the defects that can form in them. This is important because they need to understand the characteristics and behavior of different materials in order to accurately assess their condition and identify any potential defects. By having this knowledge, they can effectively interpret test results and make informed decisions about the integrity and safety of the materials being inspected. Having an exhaustive knowledge of metallurgy and being aware of the capabilities of materials to sustain deformation without forming defects are also important, but they are not the sole requirements for specialists in non-destructive testing.Rate this question:
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- 4.
Which of the following statements is correct?
- A.
The heat-affected zone of a weld is basically a homogeneous structure.
- B.
In some areas of the weld heat-affected zone, grain size can be smaller than in the unaffected base metal.
- C.
The temperature in the heat-affected zone can sometimes exceed the temperature in the fusion zone.
- D.
Transverse cracks do not occur in the heat-affected zone.
Correct Answer
B. In some areas of the weld heat-affected zone, grain size can be smaller than in the unaffected base metal.Explanation
In some areas of the weld heat-affected zone, grain size can be smaller than in the unaffected base metal. This statement is correct because during the welding process, the heat affects the microstructure of the base metal, causing changes in the grain size. In certain regions of the heat-affected zone, the rapid heating and cooling can result in a finer grain structure compared to the unaffected base metal. This can have implications on the mechanical properties and performance of the welded joint.Rate this question:
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- 5.
Metal forming such as rolling results in:
- A.
Plastic flow of the metal.
- B.
Elongation of existing defects perpendicular to the rolling direction.
- C.
Directional properties which are always beneficial for secondary forming operations.
- D.
The flattening out of defects which makes them more easily detectable by most NDT methods.
Correct Answer
A. Plastic flow of the metal.Explanation
Metal forming processes such as rolling involve the application of force to shape a metal material. This force causes the metal to undergo plastic deformation, where the metal atoms move and rearrange themselves without returning to their original positions. This plastic flow of the metal allows it to be shaped into desired forms and sizes. The other options mentioned in the question, such as elongation of existing defects, directional properties, and the flattening out of defects, may also occur during metal forming processes, but the primary outcome is the plastic flow of the metal.Rate this question:
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- 6.
What can cause stress risers?
- A.
Punch marks
- B.
Corrosion grooves
- C.
Corrosion pits
- D.
All the above answers
Correct Answer
D. All the above answersExplanation
Stress risers are areas of a material that are more prone to experiencing stress concentration, which can lead to cracks or fractures. Punch marks, corrosion grooves, and corrosion pits can all create stress risers. Punch marks are indentations made by a punch tool, which can create localized stress concentrations. Corrosion grooves are linear depressions caused by corrosion, which can weaken the material in those areas. Corrosion pits are small holes caused by corrosion, which can also create stress concentrations. Therefore, all of the given answers can cause stress risers.Rate this question:
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- 7.
When a metal (or alloy) cools from a liquid to a solid state, the lack of molten metal to feed the shrinkage will lead to:
- A.
Pipes, voids and cavities.
- B.
Sponge like appearance and hot tears.
- C.
None of the above.
- D.
both a) and b).
Correct Answer
D. both a) and b).Explanation
When a metal or alloy cools from a liquid to a solid state, the lack of molten metal to feed the shrinkage will result in the formation of pipes, voids, and cavities. These are caused by the contraction of the metal as it solidifies, creating empty spaces within the structure. Additionally, the rapid cooling can lead to a sponge-like appearance and the formation of hot tears, which are cracks or fractures that occur due to the internal stresses caused by the solidification process. Therefore, both options a) and b) are correct explanations for the consequences of the lack of molten metal to feed the shrinkage during cooling.Rate this question:
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- 8.
Which of the following is not a cause of undercutting?
- A.
Excessive amperage
- B.
Excessive travel speed
- C.
Excessive electrode diameter
- D.
Excessive restraint during welding
Correct Answer
D. Excessive restraint during weldingExplanation
Excessive restraint during welding is not a cause of undercutting. Undercutting occurs when the base metal is melted away from the weld, creating a groove or depression. It is typically caused by factors such as excessive amperage, excessive travel speed, or excessive electrode diameter. However, excessive restraint refers to the restriction of movement or expansion of the welded joint, which can lead to distortion or cracking, but it does not directly cause undercutting.Rate this question:
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- 9.
In general, where can you find heat treatment cracks?
- A.
At the centre of a weld
- B.
In areas of sudden change in thickness
- C.
On a cast plate
- D.
All the above answers
Correct Answer
B. In areas of sudden change in thicknessExplanation
Heat treatment cracks can occur in areas of sudden change in thickness because these areas experience uneven heating and cooling during the heat treatment process. The rapid temperature changes can cause thermal stresses, leading to the formation of cracks. This is a common phenomenon in materials with varying thicknesses, such as welds and cast plates. Therefore, the correct answer is "in areas of sudden change in thickness."Rate this question:
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- 10.
All indications found by NDT methods are:
- A.
Rejectable
- B.
Direct
- C.
Indirect
- D.
Dimensionally correct
Correct Answer
C. IndirectExplanation
The correct answer is "indirect." This means that the indications found by NDT methods are not directly observable or obvious. Instead, they require interpretation or inference based on the data obtained through these methods.Rate this question:
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- 11.
What type of material is typically used in 3D printing technology?
- A.
Wood
- B.
Plastic
- C.
Glass
- D.
Paper
Correct Answer
B. PlasticExplanation
In the context of 3D printing technology, plastic is one of the most commonly used materials. 3D printers can create objects by layering and melting plastic filament, allowing for the production of various plastic-based items. While other materials like metal, ceramics, and composites can also be used in 3D printing, plastic is widely accessible and used for a wide range of applications due to its versatility and ease of use in the 3D printing process.Rate this question:
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- 12.
In a situation where several methods of testing are necessary for complete inspection of a part, the preferred sequence would be:
- A.
Use penetrant inspection before ultrasonic inspection.
- B.
To use magnetic particle inspection before penetrant inspection.
- C.
to use ultrasonic inspection before penetrant inspection
- D.
Any of the above depending on the existing situation.
Correct Answer
A. Use penetrant inspection before ultrasonic inspection.Explanation
In a situation where several methods of testing are necessary for complete inspection of a part, the preferred sequence would be to use penetrant inspection before ultrasonic inspection. This is because penetrant inspection is a surface-level test that can detect surface cracks, porosity, and other defects, while ultrasonic inspection is a volumetric test that can detect internal flaws. By performing penetrant inspection first, any surface-level defects can be identified and addressed before moving on to the more comprehensive ultrasonic inspection. This ensures a more thorough inspection and increases the chances of detecting all possible defects in the part.Rate this question:
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- 13.
The inspection of a number of parts from a lot to determine the quality of the lot is called:
- A.
Lot testing
- B.
Periodic checks
- C.
Spot examination
- D.
Statistical inspection
Correct Answer
C. Spot examinationExplanation
Spot examination refers to the inspection of a number of parts from a lot to determine the quality of the entire lot. It involves randomly selecting samples from the lot and examining them for defects or other quality issues. This method is often used in manufacturing and quality control processes to ensure that the entire lot meets the required standards.Rate this question:
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- 14.
Which of the following may be considered an advantage of powder metallurgy as a manufacturing method?
- A.
Production of parts of closer tolerances
- B.
Mass production of hard-to-shape parts
- C.
Produce parts with a high strength to weight ratio
- D.
All of the above
Correct Answer
D. All of the aboveExplanation
Powder metallurgy as a manufacturing method offers several advantages. Firstly, it allows for the production of parts with closer tolerances, meaning that the final products can be made with higher precision and accuracy. Secondly, it enables the mass production of hard-to-shape parts, which would otherwise be difficult or costly to manufacture using traditional methods. Lastly, powder metallurgy can produce parts with a high strength to weight ratio, making them lightweight yet strong. Therefore, all of the mentioned advantages can be considered as benefits of powder metallurgy as a manufacturing method.Rate this question:
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- 15.
Which of the following heat treatments usually follows a hardening treatment in order to make the steel more ductile?
- A.
Annealing
- B.
Tempering
- C.
Spheroidizing
- D.
Normalizing
Correct Answer
B. TemperingExplanation
Tempering is a heat treatment process that is typically performed after hardening treatment to make the steel more ductile. During the hardening process, the steel becomes very hard but also brittle. Tempering involves reheating the hardened steel to a lower temperature and then cooling it slowly. This process helps to reduce the hardness and increase the toughness and ductility of the steel, making it less prone to cracking or breaking. Therefore, tempering is the correct answer as it is specifically used to improve the ductility of steel after hardening.Rate this question:
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- 16.
Which of the following statements is correct?
- A.
Alkaline solutions are never used to clean aluminum alloys.
- B.
Acid solutions are never used to clean aluminum alloys.
- C.
Acid solutions are usually used to clean aluminum alloys.
- D.
Alkaline solutions are usually used to clean aluminum alloys.
Correct Answer
D. Alkaline solutions are usually used to clean aluminum alloys.Explanation
Alkaline solutions are usually used to clean aluminum alloys because they are effective in removing oils, greases, and other organic contaminants from the surface of the alloy. These solutions have a high pH level, which helps to break down and dissolve the contaminants. Acid solutions, on the other hand, can corrode and damage aluminum alloys, so they are not typically used for cleaning purposes.Rate this question:
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- 17.
Suitable combinations of two different materials each with specific properties may result in a composite that:
- A.
Is better in terms of resistance to heat than either of the two components alone.
- B.
Is stronger in tension per unit weight than either of the two components alone.
- C.
Is stiffer per unit weight than either of the two components alone.
- D.
Any of the above.
Correct Answer
D. Any of the above.Explanation
When two different materials with specific properties are combined to form a composite, the resulting material can possess a combination of properties that are better than either of the individual components alone. In this case, the composite can have improved resistance to heat, increased strength in tension per unit weight, and increased stiffness per unit weight. Therefore, the correct answer is "any of the above" as the composite can have all of these properties depending on the specific combination of materials used.Rate this question:
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- 18.
Thermal conductivity of a metal is an important factor to consider in making quality weldments because:
- A.
Some metals, such as aluminum, have a low conductivity which results in weld defects due to localized heat build up.
- B.
Some metals, such as stainless steel, have a high conductivity which results in lack of fusion defects as the heat is quickly removed from the weld zone.
- C.
In some metals, such as aluminum, very high temperature gradients are produced, causing stresses during cooling.
- D.
None of the above.
Correct Answer
D. None of the above. -
- 19.
Fracture is a type of material failure. Of the following, which is another type of material failure?
- A.
Fracture mechanics
- B.
Low frequency dynamic loading
- C.
Permanent deformation
- D.
Elongation within the elastic range
Correct Answer
C. Permanent deformationExplanation
Permanent deformation refers to a type of material failure where the material undergoes a non-reversible change in shape or size due to the application of stress. Unlike fracture, which involves the breaking of a material into separate pieces, permanent deformation occurs when the material is unable to return to its original form after the stress is removed. This can happen due to the material's inherent properties or the magnitude and duration of the applied stress.Rate this question:
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- 20.
To remove iron from the ore in a blast furnace, the following materials are added to the furnace to generate the desired chemical reactions:
- A.
coke, ore and oxygen.
- B.
Bauxite, ore and air.
- C.
Coke, ore, limestone and air.
- D.
Oke, ore, limestone and bauxite.
Correct Answer
C. Coke, ore, limestone and air.Explanation
In a blast furnace, coke is added as a source of carbon, which acts as a reducing agent to remove oxygen from the iron ore. The ore itself is added as a source of iron. Limestone is added to remove impurities such as silica and alumina, forming a slag that can be easily separated from the molten iron. Finally, air is added to provide oxygen for the combustion of coke, generating heat and maintaining the high temperatures required for the chemical reactions to occur. Therefore, the combination of coke, ore, limestone, and air is necessary to remove iron from the ore in a blast furnace.Rate this question:
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- 21.
The reason for putting ingots in a soaking pit is:
- A.
to control the direction of crystallization.
- B.
To homogenize the structure and composition of the ingots.
- C.
To permit slow cooling of the ingots.
- D.
To bring them to the temperature required for rolling.
Correct Answer
D. To bring them to the temperature required for rolling.Explanation
The reason for putting ingots in a soaking pit is to bring them to the temperature required for rolling. Soaking pits are used in the steel industry to heat ingots to a specific temperature before they are rolled into desired shapes. This process allows the ingots to become more malleable and easier to work with during the rolling process. By heating the ingots in a soaking pit, they can reach the optimal temperature for rolling, ensuring that the final product has the desired properties and dimensions.Rate this question:
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- 22.
An advantage of using green sand molds over dry sand molds is:
- A.
Green sand molds are stronger then dry sand molds and thus are less susceptible to damage in handling.
- B.
Surface finish of large castings are better when using green sand molds
- C.
Over-all dimensional accuracy of the mold is better with green sand.
- D.
There is less danger of hot tearing of castings when using green sand molds.
Correct Answer
D. There is less danger of hot tearing of castings when using green sand molds.Explanation
Green sand molds provide better resistance to hot tearing, which is a common defect in metal castings. Hot tearing occurs when the solidifying metal shrinks and creates internal stresses, leading to cracks and tears in the casting. Green sand molds, which contain moisture, help to dissipate the heat more evenly during the solidification process, reducing the risk of hot tearing. This advantage makes green sand molds a preferred choice in casting processes where hot tearing is a concern.Rate this question:
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- 23.
Shielded metal-arc welding is a process of joining metals which is:
- A.
Fully automated.
- B.
Semi-automated.
- C.
Carried out manually.
- D.
All of the above.
Correct Answer
C. Carried out manually.Explanation
Shielded metal-arc welding is a process of joining metals that is carried out manually. This means that the welder directly controls the welding process, including the movement of the welding electrode and the application of the shielding gas. Unlike fully automated or semi-automated welding processes, shielded metal-arc welding requires the welder to have hands-on control and skill to ensure the proper fusion of the metals being joined.Rate this question:
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- 24.
In the resistance spot welding of low-carbon steel, the heat generated is:
- A.
Concentrated between the positive electrode and the work.
- B.
Concentrated at the interface of the two plates to be welded.
- C.
Concentrated between the negative electrode and the work.
- D.
Evenly distributed in the work between the electrodes.
Correct Answer
B. Concentrated at the interface of the two plates to be welded.Explanation
In resistance spot welding, the heat generated is concentrated at the interface of the two plates to be welded. This is because the welding process involves passing a high electrical current through the workpieces, creating resistance at the interface. The resistance causes the metal to heat up, melting and forming a weld. The heat is concentrated at the interface because this is where the resistance is highest, resulting in localized melting and joining of the two plates.Rate this question:
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- 25.
Which of the following is not a brazing process?
- A.
Furnace brazing
- B.
Induction brazing
- C.
Infrared brazing
- D.
Electron beam brazing
Correct Answer
C. Infrared brazingExplanation
Infrared brazing is not a brazing process because it does not involve the use of a filler material to join two metal pieces. Instead, it relies on the heat generated by infrared radiation to melt and join the base metals together. This process is commonly used for heating and drying applications, but it does not meet the criteria of a traditional brazing process.Rate this question:
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- 26.
Completely recrystallized hot rolled steel products have:
- A.
exactly the same mechanical properties in the longitudinal and transverse directions.
- B.
Superior mechanical properties in the direction of rolling.
- C.
Superior mechanical properties in the transverse direction.
- D.
Inferior mechanical properties than the original cast structure.
Correct Answer
B. Superior mechanical properties in the direction of rolling.Explanation
Completely recrystallized hot rolled steel products have superior mechanical properties in the direction of rolling. This is because during the hot rolling process, the steel undergoes plastic deformation, which aligns the grains in the direction of rolling. When the steel is subsequently recrystallized, new grains with a more uniform and refined microstructure are formed, resulting in improved mechanical properties in the direction of rolling, such as higher strength and better ductility. In contrast, the mechanical properties in the transverse direction may not be as superior since the grains are not as aligned in this direction.Rate this question:
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- 27.
Care must be taken not to splash steel on the walls of the mold when pouring to prevent formation of surface defects like:
- A.
Inclusions
- B.
Seams
- C.
Cold shots
- D.
Bursts
Correct Answer
C. Cold shotsExplanation
When pouring steel into a mold, it is important to avoid splashing the steel onto the walls of the mold. This is because splashing can lead to the formation of surface defects known as cold shots. Cold shots occur when small droplets of steel solidify before they fully fuse with the molten steel in the mold. These solidified droplets can create imperfections on the surface of the final product, affecting its quality and integrity. Therefore, care must be taken to prevent the occurrence of cold shots during the pouring process.Rate this question:
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- 28.
Bursts are caused by:
- A.
Casting at too low a temperature.
- B.
Forging metal which is either too hot or too cold.
- C.
Insufficient reduction in size is attempted in one forging operation.
- D.
None of the above.
Correct Answer
B. Forging metal which is either too hot or too cold.Explanation
Bursts occur when the metal being forged is either too hot or too cold. This can lead to uneven deformation and internal stresses within the metal, causing it to rupture or burst during the forging process. If the metal is too hot, it becomes more ductile and prone to tearing. On the other hand, if the metal is too cold, it becomes brittle and susceptible to cracking. Therefore, it is crucial to maintain the proper temperature range during forging to avoid bursts.Rate this question:
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- 29.
Slag inclusions in welds are caused by:
- A.
Wide weaving.
- B.
incomplete deslagging of a previous pass.
- C.
Moisture entrapped in the joint.
- D.
Both a) and b).
Correct Answer
D. Both a) and b).Explanation
Slag inclusions in welds can be caused by both wide weaving and incomplete deslagging of a previous pass. Wide weaving refers to excessive movement of the welding torch during the welding process, which can lead to the entrapment of slag. Incomplete deslagging of a previous pass refers to the failure to remove all the slag from the previous weld, resulting in its inclusion in subsequent welds. Both these factors contribute to the formation of slag inclusions in welds.Rate this question:
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- 30.
Of the following discontinuity categories, which one is considered most detrimental to the service life of an item?
- A.
Subsurface inclusions
- B.
Subsurface porosity and voids
- C.
Cracks open to the surface
- D.
All of the above
Correct Answer
C. Cracks open to the surfaceExplanation
Cracks open to the surface are considered the most detrimental to the service life of an item because they provide a direct pathway for external factors such as moisture, chemicals, and contaminants to enter the material, leading to accelerated degradation and potential failure of the item. Subsurface inclusions and subsurface porosity and voids may also weaken the material, but they do not pose an immediate threat like cracks open to the surface.Rate this question:
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- 31.
An electric current which flows steadily in one direction is:
- A.
Direct current.
- B.
Full wave current.
- C.
Half wave current.
- D.
Alternating current.
Correct Answer
A. Direct current.Explanation
An electric current that flows steadily in one direction is called direct current. This means that the flow of electrons is constant and does not change direction. Direct current is commonly used in batteries and electronic devices that require a continuous flow of electricity. It is different from alternating current, where the flow of electrons periodically changes direction. Full wave current and half wave current are not accurate descriptions of a current that flows steadily in one direction.Rate this question:
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- 32.
In the inspection of a part, the following may justify rejection of some parts:
- A.
Inherent defects
- B.
Service defects
- C.
Processing defects
- D.
All of the above
Correct Answer
D. All of the aboveExplanation
The correct answer is "all of the above." This means that all of the mentioned reasons (inherent defects, service defects, and processing defects) can justify the rejection of some parts during the inspection. Inherent defects refer to defects that are present in the part from the beginning, service defects are defects that occur during the part's use, and processing defects are defects that occur during the manufacturing or processing of the part. Therefore, any of these defects can be valid reasons for rejecting parts during inspection.Rate this question:
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- 33.
Grain boundaries are areas of a metal micro structure:
- A.
Where high melting point constituents are concentrated.
- B.
Made up of rows of atoms arrayed in straight lines.
- C.
That are not attacked by etchants and generally stand in relief during metallographic examination.
- D.
Where low melting impurities tend to concentrate.
Correct Answer
D. Where low melting impurities tend to concentrate.Explanation
Grain boundaries in a metal microstructure refer to the interfaces between individual grains or crystalline regions. These boundaries are susceptible to the concentration of impurities, particularly those with lower melting points. Impurities tend to accumulate at grain boundaries, impacting the material's properties. This phenomenon is significant in metallurgy, influencing the material's behavior and characteristics.Rate this question:
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- 34.
Steels that contain more than 0.30 percent carbon, if welded, are prone to which type of discontinuity?
- A.
Heat-affected zone cracking
- B.
Porosity
- C.
Incomplete fusion
- D.
Slag formation
Correct Answer
A. Heat-affected zone crackingExplanation
Steels that contain more than 0.30 percent carbon are prone to heat-affected zone cracking when welded. This means that when these steels are subjected to high temperatures during the welding process, the heat-affected zone (the area surrounding the weld) can develop cracks. This is due to the high carbon content, which makes the steel more susceptible to cracking when exposed to heat.Rate this question:
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- 35.
Most manufacturing defects in a tube are:
- A.
Circumferential in direction
- B.
Axial in direction.
- C.
On the outside of the tube.
- D.
Subsurface.
Correct Answer
B. Axial in direction.Explanation
Most manufacturing defects in a tube are axial in direction. This means that the defects occur along the length of the tube, rather than around its circumference or on the outside. These defects can include cracks, splits, or other imperfections that run parallel to the axis of the tube. Axial defects are typically caused by issues during the manufacturing process, such as improper handling or inadequate material quality control.Rate this question:
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- 36.
Where is the most logical place, on a casting, to look for discontinuities?
- A.
On the top surface
- B.
On the bottom surface
- C.
At internal surfaces
- D.
At junctions between light and heavy sections
Correct Answer
D. At junctions between light and heavy sectionsExplanation
Discontinuities are most likely to occur at junctions between light and heavy sections on a casting. This is because these junctions create areas of stress concentration, where the material transitions from a thicker section to a thinner section. These stress concentrations can lead to defects such as cracks or voids, making it the most logical place to look for discontinuities.Rate this question:
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- 37.
What is the cause of cracks in the heat-affected zone?
- A.
A thermal cycle that increases hardness and reduces brittleness
- B.
A thermal cycle that reduces hardness and increases brittleness
- C.
A thermal cycle that reduces hardness and brittleness
- D.
A thermal cycle that increases hardness and brittleness
Correct Answer
D. A thermal cycle that increases hardness and brittlenessExplanation
The cause of cracks in the heat-affected zone is a thermal cycle that increases hardness and brittleness. When the material undergoes a thermal cycle, it experiences rapid heating and cooling, which can lead to the formation of residual stresses. These residual stresses can cause cracking in the heat-affected zone, especially if the material becomes harder and more brittle due to the thermal cycle.Rate this question:
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- 38.
Elongated configurations of foreign substances aligned in the direction of working wrought metals are called:
- A.
Slag
- B.
Inclusions
- C.
Stringers
- D.
Worms
Correct Answer
C. StringersExplanation
Stringers are elongated configurations of foreign substances that are aligned in the direction of working wrought metals. They can be seen as long, narrow streaks or lines within the metal. These stringers can be caused by impurities or foreign particles that are present during the metalworking process. They can weaken the metal and affect its overall strength and integrity. Therefore, stringers are an important consideration in metallurgy and metalworking processes.Rate this question:
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- 39.
A defect which bears no relation to the direction of metal grains is:
- A.
intergranular corrosion
- B.
Grinding crack
- C.
Quenching crack
- D.
Lamellar tearing
Correct Answer
B. Grinding crackExplanation
A grinding crack is a defect that occurs during the grinding process of a metal. It is caused by excessive heat and pressure, leading to cracks in the metal surface. Unlike other defects mentioned, such as intergranular corrosion, quenching crack, and lamellar tearing, a grinding crack is not influenced by the direction of metal grains. The direction of metal grains is significant in other defects as it can affect the strength and integrity of the metal. However, in the case of a grinding crack, the defect is independent of the direction of metal grains.Rate this question:
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- 40.
Which of the following provides the NDT inspector with a brief outline of the steps to perform a test on a specific item?
- A.
Code
- B.
Standard
- C.
Procedure (instruction)
- D.
Specification
Correct Answer
C. Procedure (instruction)Explanation
A procedure (instruction) provides the NDT inspector with a brief outline of the steps to perform a test on a specific item. It serves as a guide for the inspector, detailing the necessary actions and sequence of steps to follow in order to carry out the test accurately and efficiently. Procedures ensure consistency and standardization in the testing process, allowing for reliable and repeatable results. Codes, standards, and specifications may provide additional guidelines and requirements, but a procedure is specifically designed to outline the steps for conducting a test.Rate this question:
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- 41.
The inverse quantity of electrical resistivity is:
- A.
Resistance
- B.
Conductivity
- C.
Reluctance
- D.
Reactance
Correct Answer
B. ConductivityExplanation
The inverse quantity of electrical resistivity is conductivity. Conductivity is a measure of how easily an electric current can flow through a material. It is the reciprocal of resistivity, which measures the opposition to the flow of electric current. Therefore, conductivity and resistivity are inversely related. Higher conductivity indicates a material that is a good conductor of electricity, while lower conductivity indicates a material that is a poor conductor.Rate this question:
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- 42.
Ultimately the function of any NDT inspection is to:
- A.
Find all defects in the part tested
- B.
Locate only those discontinuities deemed harmful in the object tested
- C.
Ensure all parts tested will be safe to use
- D.
Find all discontinuities that the proper use of the test method is capable of indicating
Correct Answer
D. Find all discontinuities that the proper use of the test method is capable of indicatingExplanation
The correct answer is "find all discontinuities that the proper use of the test method is capable of indicating". This means that the function of any NDT inspection is to identify and locate all the defects or discontinuities that can be detected using the appropriate testing method. It does not necessarily mean finding all defects in the part or ensuring the safety of all tested parts, but rather focusing on detecting the specific discontinuities that the chosen test method is capable of indicating.Rate this question:
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- 43.
Cold shuts are __________________ discontinuities.
- A.
Inherent
- B.
Processing
- C.
Service
- D.
Any of the above
Correct Answer
A. InherentExplanation
Cold shuts are inherent discontinuities.Rate this question:
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- 44.
A welding defect that occurs in the root pass and runs parallel with the weld is:
- A.
Incomplete fusion between beads.
- B.
Icicle.
- C.
Crater crack.
- D.
Incomplete joint penetration.
Correct Answer
D. Incomplete joint penetration.Explanation
Incomplete joint penetration refers to a welding defect where the weld does not fully penetrate the joint, leaving a gap or void. This defect occurs in the root pass and runs parallel with the weld. In contrast, incomplete fusion between beads refers to a defect where the individual weld beads do not fuse together properly. An icicle is a term used to describe a defect where excess filler metal protrudes from the weld. A crater crack refers to a crack that forms at the end of a weld. Therefore, the correct answer is incomplete joint penetration.Rate this question:
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- 45.
A stress corrosion crack is a defect of:
- A.
Casting
- B.
Welding
- C.
Metal forming
- D.
Service
Correct Answer
D. ServiceExplanation
A stress corrosion crack is a defect that occurs in a metal due to the combined action of corrosion and applied stress in a service environment. This means that the crack is not a result of casting, welding, or metal forming processes, but rather it develops over time during the service life of the metal. The corrosive environment, along with the presence of stress, leads to the formation and propagation of the crack. Therefore, the correct answer is service.Rate this question:
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- 46.
Which of the following factors can have a negative influence on some nondestructive tests?
- A.
Grain size
- B.
Grain orientation
- C.
Grain boundary composition
- D.
All of the above
Correct Answer
D. All of the aboveExplanation
All of the factors listed - grain size, grain orientation, and grain boundary composition - can have a negative influence on some nondestructive tests. These factors can affect the ability of the tests to accurately detect and analyze flaws or defects in materials. For example, variations in grain size or orientation can impact the propagation of ultrasonic waves, making it difficult to detect flaws. Similarly, differences in grain boundary composition can affect the magnetic properties of a material, making it challenging to perform magnetic particle testing. Therefore, all of these factors can negatively impact the effectiveness of nondestructive tests.Rate this question:
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- 47.
In which of the following welding processes is filler metal never added?
- A.
Brazing
- B.
Soldering
- C.
Arc welding
- D.
Spot welding
Correct Answer
D. Spot weldingExplanation
In spot welding, the process involves applying pressure and heat to two or more metal surfaces to join them together. Filler metal is not added in this process because the heat generated by an electric current passing through the metal surfaces causes them to melt and fuse together. Therefore, spot welding does not require the use of filler metal.Rate this question:
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- 48.
A generally smooth indentation on a cast surface resulting from the meeting of two streams of metal coming from different directions and failing to fuse is called a:
- A.
Stringer
- B.
Hot tear
- C.
Cold shut
- D.
Lap
Correct Answer
C. Cold shutExplanation
A cold shut is a generally smooth indentation on a cast surface that occurs when two streams of metal coming from different directions fail to fuse together. This happens when there is insufficient fluidity or poor gating design, causing the metal to solidify before proper fusion occurs. Cold shuts can weaken the cast and lead to structural defects.Rate this question:
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- 49.
Improper cleaning or insufficient preheating of a weldment, or moisture on the base metal or the filler metal could cause:
- A.
Crater cracks
- B.
Porosity
- C.
Undercutting
- D.
Excessive penetration
Correct Answer
B. PorosityExplanation
Porosity in a weldment can occur due to improper cleaning or insufficient preheating of the weldment. When the base metal or filler metal is not properly cleaned, contaminants such as dirt, oil, or rust can be trapped in the weld, leading to porosity. Similarly, if the weldment is not preheated adequately, moisture can be present on the base metal or filler metal, which can vaporize during the welding process and cause porosity. Therefore, porosity is a common defect that can be attributed to these factors.Rate this question:
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- 50.
Which of the following statements best differentiates between a defect and a discontinuity?
- A.
Discontinuities can propagate and become defects.
- B.
The terms are interchangeable.
- C.
All defects will lead to failure if undetected; discontinuities can be harmless.
- D.
Discontinuities are external natural boundaries only; defects are internal flaws originating from errors in processing.
Correct Answer
A. Discontinuities can propagate and become defects.Explanation
Discontinuities can propagate and become defects, whereas defects refer to internal flaws that may or may not have originated from errors in processing. This means that a discontinuity is a potential precursor to a defect, as it has the ability to develop and transform into a more significant issue. On the other hand, defects can arise from various sources, not just external natural boundaries, and can have different levels of severity. Therefore, this statement best explains the difference between a defect and a discontinuity.Rate this question:
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Jan 30, 2024Quiz Edited by
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