Manufacturing Flashcards
materials
1
Q
- Most solid metals and plastics that have reasonable strength at room temperature are called:
a. composite materials.
b. manufacturing materials.
c. allotropic materials.
d. engineering materials.
A
d. engineering materials.
2
Q
- “Manufacturing” refers to processing that starts with raw material in a bulk form and is concerned mainly with processing the raw material in a manner that changes its:
a. shape.
b. chemical form.
c. mechanical properties.
d. physical properties.
A
a. shape.
3
Q
- Frequently, dimensions are permitted to vary within specified limits. These variations are called:
a. variances.
b. fudge factors.
c. tolerances.
d. factors of safety.
A
c. tolerances.
4
Q
- Design engineers are responsible for establishing the function, appearance, quality, and cost of a product.
Regarding the role of nondestructive testing (NDT) in product design, which of the following is true?
a. As a group, designers (by their training and education) are adequately informed about NDT to establish NDT procedures and acceptance criteria.
b. When NDT appears necessary in a design, the designer should properly select the methods and techniques to be used by reference to NDT handbooks.
c. Designers should depend solely upon NDT personnel to establish acceptance criteria.
d. Designers should seek input from NDT personnel to ensure all required inspections can be performed.
A
d. Designers should seek input from NDT personnel to ensure all required inspections can be performed.
5
Q
Classification, Structure, and Solidification of Materials
1. In general, metals exist as:
a. amorphous solids.
b. mixtures and compounds of iron and carbon.
c. crystalline solids.
d. face-centered cubic lattices.
A
c. crystalline solids.
6
Q
- The terms “body-centered cubic,” “face-centered cubic,” and “hexagonal close-packed” all refer to the:
a. different sized grains that can exist at the same time in a metallic structure.
b. sequence of crystalline growth in a typical mild steel.
c. lattice structures that make up unit cells in a solid metallic structure.
d. change in a metallic structure as it undergoes plastic deformation.
A
c. lattice structures that make up unit cells in a solid metallic structure.
7
Q
- Which of the following materials is not typically be used in the as-cast state?
a. Aluminum.
b. Pure iron.
c. Zinc.
d. Magnesium.
A
b. Pure iron.
8
Q
- Processes called “austenitizing,” “annealing,” and “normalizing” are:
a. approximate equilibrium heat-treatment processes.
b. performed only on nonferrous metals.
c. cold-working processes.
d. age-hardening processes.
A
a. approximate equilibrium heat-treatment processes.
9
Q
- Annealing is usually performed to:
a. increase hardness.
b. increase strength.
c. remove strain hardening.
d. increase impact toughness
A
c. remove strain hardening.
10
Q
- The term precipitation hardening is often used interchangeably with the term:
a. age hardening.
b. recrystallization.
c. annealing.
d. work hardening.
A
a. age hardening.
11
Q
- In a tensile test on a cylindrical specimen, the strain measured on the specimen gauge length is used to calculate:
a. age hardening.
b. hardness.
c. the modulus of elasticity.
d. instability.
A
c. the modulus of elasticity.
12
Q
- Which of the following material properties are of most concern if corrosion resistance is essential?
a. Processing properties.
b. Mechanical properties.
c. Physical properties.
d. Electrochemical properties.
A
d. Electrochemical properties.
13
Q
- Attacks on metals by direct chemical action and/or electrolysis are called:
a. corrosion.
b. erosion.
c. austenitic transformations.
d. galvanization.
A
a. corrosion.
14
Q
- Which of the following groups prevent corrosion?
a. Anodizing, plating, and painting.
b. Insulating, jacketing, and strapping.
c. Annealing, normalizing, and hardening.
d. Ductility, enlarged grains, and increase hardness.
A
a. Anodizing, plating, and painting.
15
Q
- The process of returning ductility to a cold-worked low carbon steel is called:
a. precipitation.
b. recrystallization.
c. allotropic change.
d. austenitization.
A
b. recrystallization.
16
Q
- The primary goal of alloying for engineering materials is:
a. to introduce substitutional or interstitial impurities.
b. to increase the cost of manufacturing.
c. to create point or line defects in the crystal lattice.
d. to increase the strength of the nucleus.
A
a. to introduce substitutional or interstitial impurities
17
Q
Properties of Materials
1. A common industrial example of atomic diffusion is:
a. carburization of low-carbon steel.
b. electron beam melting of a nickel-based super alloy.
c. structural adhesive used in a demanding application.
d. plasma cleaning operation prior to wire-bonding.
A
a. carburization of low-carbon steel.
18
Q
- Which of the following statements is true regarding th electrical conductivity of aluminum alloys?
a. Most aluminum alloys are in the range of 70% to 96% IACS.
b. Clad aluminum takes on the conductivity of the base metal.
c. Each basic wrought aluminum alloy has a conductivity distinct from any other.
d. The conductivity of an aluminum alloy is lower than that of pure aluminum.
A
d. The conductivity of an aluminum alloy is lower than that of pure aluminum.
19
Q
- Which of the following requires permanent deformation?
a. Load below the yield strength point.
b. Low-frequency dynamic loading.
c. Strain hardening.
d. Elongation within the elastic range.
A
c. Strain hardening.
20
Q
- In Figure 1, point B is called the:
a. linear-elastic region.
b. yield strength point.
c. ultimate tensile strength.
d. modulus of elasticity.
A
b. yield strength point.
21
Q
- Tensile tests are conducted on specimens from a newly developed alloy in order to determine the ultimate tensile
strength of the material. Such tests are referred to as:
a. indirect tests.
b. physical properties tests.
c. destructive tests.
d. acoustic emission tests.
A
c. destructive tests.
22
Q
- In Figure 2, which of the following ranges indicates the effect of work hardening (to its maximum) caused by plastic flow of the material during a tensile load?
a. A–B
b. B–C
c. C–D
d. D–E
A
d. D–E
23
Q
- In Figure 2, the points represented by E and F would be closer together if the material being tested were:
a. less ductile.
b. loaded in tension.
c. loaded in lap shear.
d. more ductile.
A
a. less ductile.
24
Q
- The modulus of elasticity, or Young’s modulus, is the quotient of strength divided by strain up to the:
a. yield strength.
b. tensile strength.
c. compressive strength.
d. resistance to stress.
A
a. yield strength.
25
9. Direct hardness tests provide a measure of a material’s ability to resist:
a. bending.
b. permanent deformation or penetration.
c. tensile stresses.
d. elongation.
b. permanent deformation or penetration.
26
10. What does Figure 3 indicate?
a. Endurance limit.
b. Toughness related to strength.
c. Number of fatigue cycles.
d. Creep rate at a specific temperature and load.
d. Creep rate at a specific temperature and load.
27
11. Figure 4 typifies:
a. an S-N plot.
b. a creep test curve.
c. a stress-strain diagram.
d. a true stress-strain diagram.
a. an S-N plot.
28
Production and Properties of Common Metals
1. The reduction of iron ore, by mixing with coke, limestone, and oxygen for combustion of the coke, is accomplished in:
a. a blast furnace.
b. an open-hearth furnace.
c. a bessemer converter.
d. a basic oxygen furnace.
a. a blast furnace.
29
2. In the iron- and steel making process, “pig iron” refers to:
a. the waste material that contains high concentrations of impurities and slag and is either discarded or used as a byproduct.
b. a high-carbon, low-ductility metal produced in the blast furnace that can be used to make subsequent types of iron and steel.
c. the molten metal from the blast furnace that is not usable and is poured off into a series of crude castings called “pigs.”
d. low-cost metal used in large production factories.
b. a high-carbon, low-ductility metal produced in the blast furnace that can be used to make subsequent types of iron and steel.
30
3. An undesirable by product of the steelmaking process is:
a. coke.
b. low-carbon steel.
c. low-alloy steel.
d. slag.
d. slag.
31
4. Which of the following techniques is often used to speed up the steelmaking process?
a. Adding large amounts of carbon to the molten metal.
b. Reducing the amount of scrap steel that is often added to the molten metal.
c. Adding oxygen to the molten metal.
d. Converting the old open-hearth furnaces into electric furnaces.
c. Adding oxygen to the molten metal.
32
5. Typically, the highest quality of steel is produced in:
a. an electric furnace.
b. an open-hearth furnace.
c. a bessemer furnace.
d. a basic oxygen furnace.
a. an electric furnace.
33
6. By which of the following processes is most of the world’s steel produced?
a. Bessemer converter.
b. Electric furnace.
c. Open hearth.
d. Basic oxygen furnace.
d. Basic oxygen furnace.
34
7. What percentage of carbon is found in steel?
a. Between 3 and 4%.
b. Between 2 and 3%.
c. Less than 0.2%.
d. Less than 2%.
d. Less than 2%.
35
8. A steel with 40 points of carbon contains:
a. 40% carbon.
b. 4% carbon.
c. 0.4% carbon.
d. 0.04% carbon.
c. 0.4% carbon.
36
9. Low-carbon steel contains approximately:
a. 0.6 to 2.5% carbon.
b. 0.06 to 0.25% carbon.
c. 0.5 to 1.6% carbon.
d. 5 to 16% carbon.
b. 0.06 to 0.25% carbon.
37
10. Which of the following is true relative to the comparison of the properties of aluminum-based alloys and iron-based
alloys?
a. Iron has a lower melting point than aluminum.
b. Iron can exist in several different crystalline structures, and its properties can be controlled by heat treatment.
c. Iron can be alloyed to increase its strength, whereas aluminum is strongest in its pure state.
d. Iron is preferred in load-carrying designs, but it should not be used for any deformation type of manufacturing process.
b. Iron can exist in several different crystalline structures, and its properties can be controlled by heat treatment.
38
11. Corrosion-resistant steels having relatively high percentages of nickel and chromium are called:
a. wrought iron.
b. low-alloy steels.
c. stainless steels.
d. nonferrous steels.
c. stainless steels.
39
12. Austenitic stainless steels are paramagnetic; this means that:
a. alternating current must be used when using the magnetic particle testing method.
b. the steel is very dense and, relative to other steels, difficult to penetrate with X-rays.
c. ultrasonic testing is the logical NDT method to choose because of the coarse-grained nature of paramagnetic material.
d. the material has a very low magnetic permeability.
d. the material has a very low magnetic permeability.
40
13. Which of the following is an advantage of cast steel over wrought steels?
a. Cast steels usually have higher mechanical properties than wrought steels.
b. Cast steels have more isotropic properties than wrought steels.
c. Cast steels are more corrosion-resistant than wrought steels.
d. Cast steels cannot be heat treated and are thus less expensive to produce than wrought steels.
b. Cast steels have more isotropic properties than wrought steels.
41
14. Which of the following nonferrous metals is the most important structural material?
a. Copper alloys.
b. Nickel alloys.
c. Zinc alloys.
d. Aluminum alloys.
d. Aluminum alloys.
42
15. Many metals exhibit an increase in strength caused by plastic flow beyond the elastic limit. This effect is called:
a. twinning.
b. plastic deformation.
c. work hardening.
d. age hardening.
c. work hardening.
43
16. The heat treatment of aluminum for the purpose of hardening and strengthening:
a. is not possible with aluminum alloys because they contain no carbon and cannot undergo allotropic changes.
b. can produce tensile strengths equivalent to some carbon steels.
c. requires the use of special furnaces and is rarely done as a practical application.
d. requires that iron and carbon be alloyed for the best results.
b. can produce tensile strengths equivalent to some carbon steels.
44
17. Brass and bronze are alloys of zinc, tin, and a large percentage of:
a. beryllium.
b. copper.
c. lead.
d. nickel.
b. copper.
45
18. MonelTM and InconelTM are:
a. nickel alloys.
b. steel alloys.
c. magnesium alloys.
d. aluminum alloys.
a. nickel alloys.
46
19. Which of the following metals has a density approximately two-thirds that of aluminum?
a. Magnesium.
b. Iron.
c. Copper.
d. Nickel.
a. Magnesium.
47
20. A high-strength, low-density, corrosion-resistant metal alloy of significance in the aircraft, marine, and chemical processing industries is:
a. tungsten.
b. zinc.
c. titanium.
d. magnesium.
c. titanium.
48
Polymers, Ceramics, and Composites
1. Which of the following statements is true concerning plastics following their initial polymerization?
a. Thermoplastics can be endlessly reshaped.
b. Thermosetting plastics do not soften, but char and deteriorate when reheated.
c. All plastics are synthetic and contain no natural materials.
d. Plastics have a complex molecular structure, making it expensive to bind with other materials.
b. Thermosetting plastics do not soften, but char and deteriorate when reheated.
49
2. Based on the strength-to-weight ratio:
a. no plastic materials can compare with metals.
b. plastics, as a group, are superior in strength to most ferrous metals.
c. some plastics, including nylon, may have strengths greater than some steels.
d. plastics, being chemically inert, retain their strength longer than carbon steels in corrosive environments.
c. some plastics, including nylon, may have strengths greater than some steels.
50
3. Which of the following statements is true regarding plastics processing?
a. Unlike metals, plastics must be processed without the addition of heat.
b. All plastic molding processes use liquid-state materials introduced into the mold cavity.
c. Injection molding can be done only with
thermosetting materials.
d. Both thermoplastics and thermosetting plastics may be processed by molding, casting, and extrusion.
d. Both thermoplastics and thermosetting plastics may be processed by molding, casting, and extrusion.
51
4. Reinforced plastic molding involves the use of:
a. thermosetting plastics and fibrous reinforcement materials.
b. thermosetting plastics and metallic powder reinforcement.
c. thermoplastics and wood fiber reinforcement materials.
d. thermoplastics and metallic powder reinforcement.
a. thermosetting plastics and fibrous reinforcement materials.
52
5. The major difference between materials classified as “composites” and those classified as “mixtures” is that:
a. composites contain metallic constituents and mixtures are nonmetallic.
b. mixtures start as liquids blended together and composites start as solids.
c. mixtures are elastomeric, whereas composites are characterized as having at least one plastic component.
d. mixtures are a type of composite with random orientation and shape of the constituents.
d. mixtures are a type of composite with random orientation and shape of the constituents.
53
6. Which of the following statements is true concerning composite materials?
a. Composite materials are engineered from one or more reinforcing agents and a matrix to increase strength and reduce weight.
b. When composite materials are cured, the
constituents lose their original identity and form chemical compounds with one another.
c. A unique feature of composite materials is that their tensile strength frequently exceeds the strength of the strongest constituent.
d. Composites are usually formed into complex three-dimensional shapes with each dimension approximately equal to the other two.
a. Composite materials are engineered from one or more reinforcing agents and a matrix to increase strength and reduce weight.
54
7. Which of the following materials is typically considered when the application requires high compressive strength?
a. Glass fibers.
b. Aramid fibers.
c. Carbon fibers.
d. Ceramic fibers.
c. Carbon fibers.
55
8. Which of the following statements is true concerning honeycomb?
a. The function of a honeycomb core is to lighten, stiffen, and strengthen by utilizing the “sandwich principle.”
b. In honeycomb, the walls of the cellular core material are aligned parallel with the plane of the face sheets.
c. Honeycomb containing nonmetallic elements can be bonded by adhesives, brazing, or diffusion welding.
d. Honeycomb combining metallic and nonmetallic elements cannot be used in cryogenic service due to the permeability of the nonmetallic elements.
a. The function of a honeycomb core is to lighten, stiffen, and strengthen by utilizing the “sandwich principle.”
56
9. The mechanism of adhesion may combine mechanical interlocking with:
a. stickiness of the adhesive.
b. roughness of the adherends.
c. dynamic mechanical forces.
d. cohesion.
d. cohesion.
57
10. Which of the following tests uses a pendulum to break a specimen that is notched and supported on both ends,
with the result of measuring energy absorption?
a. Creep test.
b. Charpy test.
c. Fatigue test.
d. Transverse rupture test.
b. Charpy test.
58
Casting
1. The design of the casting is important because the quality of the finished product can be adversely affected by:
a. liquid metal pour volume, gate locations, and nonuniform casting sections.
b. mold temperature, slow post casting cooling, and magnetization.
c. riser baffles, pour cup angle, and mold parting lines.
d. alloy element segregation, change in metal phase, and sprue spacing.
a. liquid metal pour volume, gate locations, and nonuniform casting sections.
59
2. The part of the casting where the gate or riser attaches:
a. is the area used to establish reference standards for cast materials.
b. provides the best quality material because of rapid cooling in this area.
c. may provide a concentration point for discontinuities.
d. is designed to create nonuniform section thicknesses.
b. provides the best quality material because of rapid cooling in this area.
59
3. Risers, feeders, or feed heads in castings serve to provide sources of molten metal to compensate for:
a. misruns.
b. cold shuts.
c. dendritic grain growth.
d. shrinkage.
d. shrinkage.
60
4. Which of the following may cause a discontinuity even though its intended purpose is to prevent shrinkage cavities by absorbing heat from the molten metal in the center of the casting?
a. Riser.
b. Internal chill.
c. Core.
d. Chaplet.
b. Internal chill.
61
5. In a casting, shrinkage occurs:
a. only after the transformation from liquid to solid.
b. only during the transformation from liquid to solid.
c. before, during, and after the transformation from
liquid to solid.
d. only when the metal is in the liquid state.
c. before, during, and after the transformation from liquid to solid.
62
6. Large voids or porosity in a casting result from:
a. turbulent flow of the molten metal during pouring.
b. alloy element segregation.
c. molten metal boiling because of superheat.
d. gas evolution before and during solidification.
d. gas evolution before and during solidification.
63
7. During the solidification of a casting, the shrinkage that occurs:
a. may cause cavities that are enlarged by the evolution of gases.
b. may cause porosity and shrinkage cavities primarily in the outer surfaces where the metal cools first.
c. requires that the pattern used be slightly smaller than the desired dimension of the finished casting.
d. may be eliminated by investment casting.
a. may cause cavities that are enlarged by the evolution of gases.
64
8. A casting process used to produce elongated shapes by drawing solidified metal from a water-cooled mold
backed by molten metal is:
a. centrifugal casting.
b. continuous casting.
c. draw casting.
d. extrusion.
b. continuous casting.
65
9. Green sand casting molds include:
a. sand, clay, and water.
b. sand, wax, and solvent.
c. sand, refractory metals, and water.
d. sand, carbon, and green clay.
a. sand, clay, and water.
66
10. Which of the following NDT methods can be commonly used to inspect castings for unfused chaplets and to determine that all the core materials have been removed?
a. Ultrasonic testing.
b. Magnetic particle testing.
c. Radiographic testing.
d. Electromagnetic testing.
c. Radiographic testing.
67
11. Mold material in the form of inserts that exclude metal flow and thus form internal surfaces or passages in a casting are called:
a. chills.
b. chaplets.
c. cores.
d. patterns.
c. cores.
68
12. Small metal supports used to support and position cores become part of a casting by fusing with the molten metal.
Such devices are called:
a. core hangers.
b. chills.
c. risers.
d. chaplets.
d. chaplets.
69
13. Casting molds made by covering a heated metal pattern with sand that is mixed with particles of thermosetting
plastic are called:
a. green sand molds.
b. shell molds.
c. die casting molds.
d. permanent molds.
b. shell molds.
70
14. Another term for precision casting and the lost-wax process is:
a. investment casting.
b. die casting.
c. metal mold casting.
d. shell mold casting.
a. investment casting.
71
15. Permanent molds are most frequently made of:
a. ceramics.
b. fused sand and plastic.
c. metal.
d. plaster.
c. metal.
72
16. A casting process used to produce hollow products like large pipes and hollow shafts is:
a. investment casting.
b. blow casting.
c. core casting.
d. centrifugal casting.
d. centrifugal casting.
73
17. Which of the following metals has low strength and high corrosion resistance, and is used largely in die-casting
operations?
a. Zinc.
b. Aluminum.
c. Magnesium.
d. Manganese.
a. Zinc.
74
18. Which of the following is true regarding solidification of molten metal in a casting mold?
a. The metal cools at a constant rate, thus providing fine equiaxed grains throughout.
b. Cooling takes place in phases having different rates that produce different types of grain structure in different sections of the casting.
c. Solidification occurs at a constant rate, beginning at the interior of the casting and progressing outward.
d. Thick sections tend to cool more rapidly than thin sections because thin sections consist mostly of fine equiaxed grains.
b. Cooling takes place in phases having different rates that produce different types of grain structure in different sections of the casting.
75
19. The term used to describe a discontinuity in a casting that occurs when molten metal interfaces with already
solidified metal with failure to fuse at the interface is:
a. hot tear.
b. cold shut.
c. inclusion.
d. segregation.
b. cold shut.
76
Metal Forming
1. The advantages of deformation of metals as a manufacturing process are:
a. consistent duplication, fast production, low cost for high volumes.
b. low tooling cost, less NDT, doesn’t require heat treatment.
c. easier to recycle, better grain structure, doesn’t require special materials.
d. more labor, only makes simple shapes, holds finishes well.
a. consistent duplication, fast production, low cost for high volumes.
77
2. Which of the following would have the least ductility?
a. Cold-rolled steel plate.
b. Hot-rolled steel plate.
c. Cast iron.
d. Hot-rolled aluminum plate.
c. Cast iron.
78
3. Forged products invariably exhibit:
a. high susceptibility to corrosion.
b. lower strength than their cast counterparts.
c. directional properties.
d. poor weldability.
c. directional properties.
79
4. The manufacturing process used most to form metals into three-dimensional shapes is:
a. casting.
b. machining.
c. welding.
d. forging.
d. forging.
80
5. Which of the following product forms is generally selected for high strength and controlled property directionality?
a. Castings.
b. Forgings.
c. Extrusions.
d. Hot-rolled flat stock.
b. Forgings
81
6. NDT is often used on products intended for secondary operations to:
a. ensure that further operations are not performed on material that contains discontinuities that could cause rejection of the manufactured part.
b. determine that discontinuities do not exist in the material that could damage the rolling mills and other equipment.
c. determine the ductility of the material after the rolling operation is complete.
d. accurately determine the compressive strength of the material after it passes through the rolling mill.
a. ensure that further operations are not performed on material that contains discontinuities that could cause rejection of the manufactured part.
82
7. An NDT method best suited to locating discontinuities caused by inclusions rolled into steel plate is:
a. radiographic testing.
b. ultrasonic testing.
c. visual testing.
d. magnetic particle testing.
b. ultrasonic testing.
83
8. Slabs, blooms, and billets are:
a. the shapes that the ingot is rolled into prior to a variety of secondary operations.
b. the three consecutive stages that the metal goes through during the production of products such as angle iron and channel iron.
c. types of discontinuities that occur during the hot rolling of steel.
d. the three different shapes produced during typical cold-rolling operations.
a. the shapes that the ingot is rolled into prior to a variety of secondary operations.
84
9. Before cold-finishing operations can be done on hot rolled materials, cleaning is often done by immersing the hot-rolled material in acid baths in a process called:
a. degreasing.
b. descaling.
c. pickling.
d. anodizing.
c. pickling.
85
10. During the steelmaking process, a large number of discontinuities such as slag, porosity, and shrinkage cavities exist in the top of the ingot. These discontinuities are:
a. mostly eliminated in subsequent hot working due to the pressure that “welds” the void shut.
b. located with NDT at later stages of production.
c. almost nonexistent with modern steelmaking processes.
d. removed by cropping up to one-third off the top of the ingot.
d. removed by cropping up to one-third off the top of the ingot.
86
11. Discontinuities with their origin in the original ingot can be reduced in severity by the closing and welding of voids and the breaking up and elongation of inclusions by
which of the following processes?
a. Cold working.
b. Hot rolling.
c. Heat treatment.
d. Welding.
b. Hot rolling.
87
12. Cold-rolling sheet steel usually begins with a material that:
a. has been completely inspected with an automated radiographic system.
b. has been previously hot rolled to dimensions close to the size of the finished product.
c. has less ductility and greater hardness than typical hot-rolled steel.
d. will have a lower yield and tensile strength after cold working.
b. has been previously hot rolled to dimensions close to the size of the finished product.
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13. Which of the following statements is true concerning deformation processes?
a. Hot working usually follows cold working.
b. Hot working must be followed by heat treatment.
c. Cold working usually follows hot working.
d. Cold working renders brittle material more ductile.
c. Cold working usually follows hot working.
89
14. Machinability and fatigue resistance are improved in most metals that have been:
a. hot worked.
b. cold worked.
c. heat treated.
d. cast.
b. cold worked.
90
15. The manufacturing process performed principally on flat products and bars that improves hardness, strength, surface finish, and dimensional accuracy is:
a. cold rolling.
b. hot rolling.
c. forging.
d. sintering.
a. cold rolling.
91
16. Most seamless tubing made without welds is processed by:
a. casting.
b. piercing.
c. cold rolling.
d. brazing.
b. piercing.
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17. With flat products such as cold-rolled strip and sheet, ultrasonic and radiation gauges may be used to provide an accurate measurement of:
a. strain rate.
b. surface roughness.
c. thermal properties.
d. thickness.
d. thickness.
93
18. Most steel pipe is produced by forming and:
a. drawing.
b. welding.
c. forging.
d. pressing.
b. welding.
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19. A process that requires the use of large, powerful equipment that forms ductile material into a wide variety of long-length, uniform, cross-sectional shapes best describes:
a. forging.
b. powder metallurgy.
c. extrusion.
d. die casting.
c. extrusion.
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20. Among other factors, the advantageous effects of recrystallization depend upon the:
a. rate of heating.
b. temperature at which deformation takes place.
c. presence of carbon in excess of 25% for steels.
d. presence of silicon in excess of 0.1% for steels.
b. temperature at which deformation takes place.
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21. In drawing and deep drawing, the final shape often can be completed in a series of draws, each successively deeper.
What process performed between draws might effectively reduce the number of draws required?
a. Recrystallization.
b. Pickling.
c. Etching.
d. Hardening heat treatment.
a. Recrystallization.
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22. Spinning can be used to form:
a. spherical deep-drawn shapes.
b. cemented carbide cutting tools.
c. rectangular sheet metal tanks.
d. solid spheres.
a. spherical deep-drawn shapes.
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23. Deep drawing, blanking, punching, and shearing are operations most commonly applied to:
a. castings.
b. slabs or blooms.
c. extracted ore.
d. sheet metal.
d. sheet metal.
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24. Most new developments in sheet-metal forming typically use nonconventional energy sources. What is a common
feature of these processes?
a. The use of lasers for controlled heat input.
b. The use of cryogenics to super-cool the metal prior to forming.
c. The use of energy sources that release large amounts of energy in a very short time.
d. The use of large autoclaves that contain both the tooling and the metal being formed.
c. The use of energy sources that release large amounts of energy in a very short time.
100
25. Chemical catalysts, filter elements, and bearings are commonly made by:
a. powder metallurgy.
b. galvannealing.
c. vacuum metallization.
d. hot isostatic pressing.
a. powder metallurgy.
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26. Powder metallurgy provides two unique advantages in metals processing. One is the capability to produce shapes
and objects of refractory metals that are extremely difficult or impractical to melt; the other is to:
a. economically produce metals with extremely low melting temperatures.
b. produce metal shapes with controlled porosity.
c. produce metals that can be easily machined by electrochemical processes.
d. produce metals that are corrosion resistant.
b. produce metal shapes with controlled porosity.
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27. A major purpose of pressing the metal powders during powder metallurgy processing is to:
a. squeeze out excess moisture.
b. further refine the grains.
c. compact the powders into mechanical and atomic closeness.
d. decrease the contact area.
c. compact the powders into mechanical and atomic closeness.
103
28. Powder metallurgy sintering:
a. is performed above the material’s melting temperature.
b. allows parts to be hot worked, heat treated, or machined afterward.
c. results in a maximum of 70% theoretical density.
d. leaves parts in a fragile state subject to handling damage.
b. allows parts to be hot worked, heat treated, or machined afterward.
104
29. In the powder metallurgy process, sintering is:
a. in most cases a fully solid-state process.
b. never a fully solid-state process.
c. principally done at room temperature.
d. always done at elevated temperature and high pressure.
a. in most cases a fully solid-state process.
