ME 321-Final Review- with extra

What are three ways in which a threaded fastener can fail during tightening?

(1) Stripping of the bolt or screw threads, (2) stripping of the internal fastener threads, and (3) excessive tensile load on the cross-sectional area of the bolt or screw.

Tumbling is a mass finishing process that is also known by which one of the following names: (a) barrel finishing, (b) centrifugal finishing, (c) roll finishing, (d) tumble finishing, or (e) vibratory finishing?

(a) barrel finishing,

The biggest contributors to costs in arc welding are labor and equipment; labor cost is more significant in manual welding, and equipment cost is more significant in automated and robotic welding: (a) True or (b) false?

(a) True

In electroplating, the source of the plating metal is the (a) anode or (b) cathode?

(a) anode

In diffusion, the concentration of the impregnated element in the substrate is greatest (a) at the surface or (b) just beneath the surface?

(a) at the surface

The maximum possible draft in a rolling operation depends on which two of the following parameters: (a) coefficient of friction between roll and work, (b) roll diameter, (c) roll velocity, (d) stock thickness, (e) strain, and (f) strength coefficient of the work metal?

(a) coefficient of friction between roll and work, (b) roll diameter

The cleaning fluids in ultrasonic cleaning are generally aqueous solutions containing which of the following types of chemicals: (a) acids, (b) alkaline detergents, (c) emulsified oils, or (d) trichloroethylene?

(b) alkaline detergents

Acetylene must be stored in which one of the following types of containers: (a) cylinders containing a porous substance saturated with acetate, (b) cylinders containing a porous substance saturated with acetone, (c) pressurized cylinders, (d) pressurized cylinders containing a porous substance saturated with acetate, or (e) pressurized cylinders containing a porous substance saturated with acetone?

(b) cylinders containing a porous substance saturated with acetone

Which three of the following are advantages of brazing compared to fusion welding: (a) annealing of the base parts is a by-product of the process, (b) dissimilar metals can be joined, (c) less heat and energy are required, (d) metallurgical improvements occur in the base metals, (e) multiple joints can be brazed simultaneously, (f) parts can be readily disassembled, and (g) joints are stronger than in welding?

(b) dissimilar metals can be joined, (c) less heat and energy are required, (e) multiple joints can be brazed simultaneously,

For metallurgical reasons, it is desirable to melt the weld metal with minimum energy input. Which one of the following heat sources is most consistent with this objective: (a) high power, (b) high power density, (c) low power, or (d) low power density?

(b) high power density,

The maximum value of true strain experienced by the work in open-die forging is which one of the following: (a) natural logarithm of the final height of the work over the starting height, (b) natural logarithm of the starting height of the work over the final height, (c) the final height of the work divided by the starting height, or (d) the starting height of the work divided by the final height?

(b) natural logarithm of the starting height of the work over the final height,

The true strain experienced by the work in rolling is which one of the following: (a) natural logarithm of the final thickness over the starting thickness, (b) natural logarithm of the starting thickness over the final thickness, (c) the final thickness divided by the starting thickness, or (d) the starting thickness divided by the final thickness?

(b) natural logarithm of the starting thickness over the final thickness,

Glass is distinguished from the other two categories of ceramics by the fact that it is (a) crystalline or (b) noncrystalline?

(b) noncrystalline

Which of the following mass finishing methods requires less processing time per batch: (a) tumbling or (b) vibratory finishing?

(b) vibratory finishing?

Aluminum is easy to weld because its melting temperature is relatively low: (a) True or (b) false?

(b). False:: Aluminum melts too easily for good welding.

Diffusion welding involves the application of heat and pressure, usually in a controlled atmosphere, at temperatures close to but below the melting point (about 0.9 Tm) of the metal: (a) True or (b) false?

(b). The temperatures in diffusion welding are about 0.5 Tm of the metal.

Which one of the following welding operations generates the lowest power density: (a) arc welding, (b) electron beam welding, (c) oxyfuel welding, or (d) resistance welding?

(c) oxyfuel welding,

Which two of the following are destructive as opposed to nondestructive methods used in welding inspection and testing: (a) magnetic particle tests, (b) radiographic tests, (c) shear tests, (d) tensile tests, and (e) ultrasonic tests?

(c) shear tests, (d) tensile tests

The area reduction in wire drawing is which one of the following: (a) natural logarithm of the final cross-sectional area of the work over the starting cross-sectional area, (b) natural logarithm of the starting cross-sectional area over the final cross-sectional area, (c) the difference between the starting and final cross-sectional areas divided by the starting cross-sectional area, (d) the final cross-sectional area divided by the starting cross-sectional area, or (e) the starting cross-sectional area divided by the final cross-sectional area?

(c) the difference between the starting and final cross-sectional areas divided by the starting cross-sectional area,

Which one of the following is the reason why heat transfer factors are higher in arc welding processes that use consumable electrodes than in arc welding processes that use nonconsumable electrodes: (a) temperatures in arc welding processes that use consumable electrodes are higher, (b) the flux used in arc welding processes that use consumable electrodes reduces heat transfer away from the molten metal, or (c) the heat used to melt the consumable electrode is transferred to the welding operation as molten metal?

(c) the heat used to melt the consumable electrode is transferred to the welding operation as molten metal

Vapor degreasing is a form of which one of the following: (a) acid cleaning, (b) alkaline cleaning, (c) electrolytic cleaning, (d) emulsion cleaning, or (e) solvent cleaning?

(d) solvent cleaning,

The extrusion ratio is which one of the following: (a) natural logarithm of the final cross-sectional area of the work over the starting cross-sectional area, (b) natural logarithm of the starting crosssectional area over the final cross-sectional area, (c) the final cross-sectional area divided by the starting cross-sectional area, or (d) the starting cross-sectional area divided by the final crosssectional area?

(d) the starting cross-sectional area divided by the final cross sectional area?

Mechanical plating uses mechanical energy to build a metallic coating onto a surface and is carried out using which one of the following types of equipment: (a) autoclave, (b) centrifuge, (c) spray gun, (d) tumbling barrel, (e) vacuum chamber, or (f) vibrating barrel?

(d) tumbling barrel

Ion implantation is sometimes used as a substitute for certain coating processes, where its advantages are which two of the following: (a) better corrosion protection, (b) good adhesion, (c) increased electrical conductivity, (d) increased electrical resistance, (e) no discontinuity between coating and substrate, or (f) no problems with waste disposal?

(e) no discontinuity between coating and substrate, or (f) no problems with waste disposal

Sputtering is a form of which one of the following: (a) chemical vapor deposition, (b) defect in arc welding, (c) diffusion, (d) ion implantation, or (e) physical vapor deposition?

(e) physical vapor deposition

This clear clamshell packaging

(i) I'd use PET, (ii) because it is both clear and food-safe, and (iii) I'd vacuum mold it. (iv) I'd mold it across the hinge, as shown above.

Clear plastic tubing

(i) I'd use acrylic, but that could also be polystyrene or PET, (ii) because it is clear (transparent), and (iii) I'd extrude it. (iv) The extrusion would result in the molecular alignment being along the pipe axis, as shown in the above.

Plastic bags that come on a roll

(i) I'd use polyethylene, (ii) because it is inexpensive, easily formed, and food-safe, and (iii) I'd blow mold it. (iv) For a low-strength part, the flow direction does not matter, but the blow-molding process starts with a thin sheet, which is made by extrusion, so the resulting molecular alignment would be crossways, either horizontal or vertical in the above.

Egg holder for camping

(i) I'd use polypropylene, (ii) because of the living hinge, and (iii) I'd injection mold it. (iv) The plastic should flow across the living hinge, as shown in the above.

What are all of the assembly processes?

. Bolting . Rivets . Interference fits . Snap Fit

What is electroplating process?

. Electrolytic process in which metal ions in electrolyte solution are deposited onto a cathode work part.

What is the difference between tempered glass and annealed glass?

. Tempered glass is heated to the plastic range, then cooled with air to get a differential stress in the glass. . Annealed glass= Heating to elevated temperature and holding to eliminate stresses and temperature gradients; then slow cooling to suppress stress formation

what is diffusion process?

..Alteration of surface layers of material by diffusing atoms of a different material (usually an element) into surface, usually at high temperatures. The surface still contains a high proportion of substrate material Surface treatments to increase hardness and wear resistance

What is ion implantation.

..Embedding atoms of one (or more) foreign element(s) into a substrate surface using a high-energy beam of ionized particle ..Produces a much thinner altered layer and different concentration profile than diffusion.

What is isostatic pressing? Powder injection molding? Powder rolling, extrusion forging?

..isostatic- pressed from all sides ..Powder injection molding- 50% -85% of polymer is particles of metal .. Powder is rolled into sheet and then sinntered

What is the temperature in which PM parts are sintured too? What is the bond?

.7 -.9 Tm , the bond is the reduction in surface energy. They shrink a little in the molds.

What are the basic steps of the conventional press and sinter methods for powered metals.

1. Blend the powder till Homogeneous. 2. Compact in mold 3. pre heat 4. sinter 5. Cool in controlled manner.

What are the advantages of the shape-casting process?

1. Complex part geometries are possible. 2. some casting operations are net shape processes, meaning that no further processing is needed. 3. very large parts possible 4. casting can be done with an metal that can be melted. 5. Some casting processes are suited for mass production.

What are the two predominate types of casting molds?

1. Expendable molds 2. permanent molds.

Near net shape and net shape processes are ones in which little or no additional machining is required to complete the part: (a) True or (b) false?

A) True

Which one of the following gases is the most commonly used in sputtering and ion plating: (a) argon, (b) chlorine, (c) neon, (d) nitrogen, or (e) oxygen?

A) argon

What are some of the advantages of hot working relative to cold working?

Advantages of hot working relative to cold working are (1) the shape of the work part can be significantly altered, (2) lower forces and power required, (3) metals that usually fracture in cold working can be hot-formed, (4) strength properties are generally isotropic, and (5) no strengthening of the part due to strain hardening.

What are the advantages of snap fitting?

Advantages of snap fitting include (1) the parts can be designed with self-aligning features for ease of mating, (2) no tooling is required, and (3) the method is fast.

List the main advantages and disadvantages of welding as a joining mechanism:

Advantages: Permanent, can be cost-effective, does not require other hardware, can be done on-site. Disadvantages: Permanent, can be costly in terms of labor, requires great skill, flaws may not be immediately evident.

What are the advantages and disadvantages to thixoforming?

Advantages: Complex geometries can be produced, net shape, no porosity, good mechanics of resulting microstructure, good tolerances, good surface finish Disadvantages: Feedstock must be specially prepped; cost calculations must be carefully done; can be less expensive than casting, but not necessarily.

Describe how thixoforming is accomplished. Describe the behavior of metal that we exploit to accomplish thixoforming.

An applied shear stress causes a decrease in viscosity, enabling flow.

In anodizing, the work part to be coated is which one of the following during the electrolytic process: (a) anode or (b) cathode?

Anode

The applied force in an extrusion operation is based on which of the following flow stress values: (a) average flow stress or (b) instantaneous flow stress?

Answer A), average flow stress

The bonding between metal plates in explosive cladding is caused by rapid diffusion between the plates: (a) True or (b) false?

Answer. (b). The bonding between plates results from metallurgical bonding and mechanical interlocking, not diffusion.

Strain rate sensitivity is greatest under which one of the following situations: (a) cold working, (b) hot working, or (c) warm working?

Answer. (b)., Hot Working

The dividing line between warm working and cold working is usually taken to be which one of the following temperatures relative to the melting point of the given metal, where Tm = the melting temperature on an absolute temperature scale: (a) 0.1Tm, (b) 0.2Tm, (c) 0.3Tm, or (d) 0.4Tm?

Answer. (c). 0.3*Tm

The property of a metal that results in increasing values of flow stress as it is deformed is which one of the following: (a) ductility, (b) hardness, (c) strain hardening, (d) tensile strength, or (e) yield strength?

Answer. (c). Strain Hardening

The tooling is called a die in all of the following bulk deformation processes except which one: (a) drawing, (b) extrusion, (c) forging, or (d) rolling?

Answer. (d).rolling?

What is a riser used for in a casting mold?

As a reservoir in the mold that serves as a source of liquid to compensate for shrinkage of the casting during solidification.

Describe windshield glass, how it is manufactured, and why it is done that way. What is the unique property of the finished product?

Automobile glass is conventional glass, with two pieces of glass on either side of a tough polymer sheet. Should this laminated glass fracture, the glass splinters are retained by the polymer sheet and the windshield remains relatively transparent..

Lubricants used in hot working are the same as those used in cold working: (a) True or (b) false?

B), False

Filler metals are never used in any of the oxyfuel gas welding processes: (a) True or (b) false?

B. False

What are the mechanical cleaning methods?

Blast Finishing-sand blasting Shot Peening- metal shot to cold form the surface Mass Finishing- In a tumbler, a vibrator barrell

What is borosilicate glass and what is its defining useful property? What is it used for?

Borosilicate glass has boron added to make it resistant to thermal shock. It is used for bakeware, and other applications that involve big temperature changes.

The part produced in a sheet metal operation is called which one of the following: (a) formed part, (b) pressed part, (c) stamping, or (d) workpiece?

C. Stamping

Is ceramic stronger in compression or tension? Why?

Ceramic is stronger in compression because it is brittle and fails via brittle fracture.

What is the difference between deep drawing and bar drawing?

Deep drawing is a sheet metal forming process used to fabricate cup-shaped parts; bar drawing is a bulk deformation process used to reduce the diameter of a cylindrical work part.

Among casting processes, which of the following can achieve closer tolerances, sand casting or die casting?

Die Casting

What are the three kinds of feedstock that can be used for thixoforming?

Either bulk billets, coarse particulates, or powders

Brazing fluxes are used to clean the part surfaces of oxides, oils, and other contaminants that would interfere with the process: (a) True or (b) false?

False (b). The part surfaces must be cleaned prior to the brazing operation using chemical and/or mechanical cleaning treatments. A flux does not substitute for these treatments.

What is the purpose of annealing glass after it is worked?

Glass is annealed to relieve internal stresses.

Is glass stronger in compression or tension? Why?

Glass is stronger in compression because it is brittle and fails via brittle fracture.

Why is electrical wire made of copper?

High electricaly conductive, conductive= (1/restivity) per unit length, and very form-able

What are ceramic refractory brick properties good for?

High melting point, high combustion point, low coefficient of thermal expansion, high heat capacity,

Describe the main advantages and disadvantages of polymer-matrix composites.

High strength-to-weight ratio (strong and lightweight). There could be a variety of acceptable answers here—high stiffness, corrosion resistance, abrasion resistance, etc.

What is the difference between infiltration and impregnation in PM?

Impregnation- when oil or other fluids are added to part pore space Infiltration- When pores are filled with molten metal to increase density

What is the difference between a shrink fit and expansion fit in assembly?

In a shrink fit, the outside part is expanded by heating to fit over the mating component. Then cooling causes an interference fit with the component. In an expansion fit, the internal part is cooled so that it can be readily inserted into the mating component. Then, upon warming to room temperature, it expands to cause an interference fit with its mating part.

How do brazing and soldering differ from the solid-state welding processes?

In brazing and soldering, a filler metal is added, whereas in solid state welding no filler metal is added.

How does increasing temperature affect the parameters in the flow curve equation?

Increasing temperature decreases both K and n in the flow curve equation.

What is the effect of increased workpiece temperature on the strain rate sensitivity exponent?

Increasing workpiece temperature increases the strain rate sensitivity exponent.

Among casting processes, which of the following provides the better surface finish, sand casting or investment casting?

Investment casting.

Why is aluminum used in aircraft frames?

It is strong, lightweight, and resistant to fatigue. ( Visual crack propagation. also)

What is centrifugal spraying used for?

It is used for the formation of thin fibers to make insulation.

Why is Pyrex good for bake wear?

Low coefficient of thermal expansion; high resistance to thermal shock ; decent thermal conductivity(although not as good as metal)

Describe the main advantages and disadvantages of powder metallurgy, as compared against casting or forming of metals.

Main advantages: Mixtures can be made that cannot be formed by other means; lubricants, corrosion inhibitors, etc can be impregnated in the metal. Other advantages: Can get good detail, net shape. Disadvantages: Cost

What are some of the methods used to apply adhesives in industrial production operations?

Methods include (1) manual brushing, (2) use of manual rollers, (3) silk screening, (4) use of flow guns, (5) spraying, (6) automatic dispensers, and (7) roll coating.

What is the Gas atomization process?

Molten metal is sprayed in a stream of high velocity gas, ( like siphon on paint gun), this creates the small particles.

Plastic bottle

Note that there is NO nubby mark in the middle of the bottom. (i) I'd use polyethylene, (ii) because it is both inexpensive and food-safe, and (iii) I'd blow mold it. (iv) For a low-strength part, the flow direction does not matter, but the blow molding process starts with a thin sheet, which is made by extrusion, so the resulting molecular alignment would be vertical, as in the upper photo.

These plastic bottles

Note the nubby mark in the center of the bottom. Bottom of some of them: (i) I'd use PET, (ii) because it is both clear and food-safe, and (iii) I'd injection blow mold it. (iv) The bottle blank is injection molded first and then blown to the shape of the bottle, so the predominant alignment may be either vertical or circumferential, as shown in the first two bottles above.

Which are some of the unique properties of glass? How is it distinguished from the other categories of ceramic?

Optically clear, chemically inert, hard, brittle... (there could be many answers)

What are some of the reasons why assemblies must be sometimes disassembled?

Reasons why assemblies must be sometimes disassembled include (1) for maintenance and repair service, (2) to replace worn-out components, and (3) to make adjustments.

Describe the rolling process.

Rolling is a compression bulk deformation process in which the thickness of a slab or plate is reduced by two opposing cylindrical tools called rolls, which rotate so as to draw the work into the gap between them and squeeze it.

Explain why rubber is vulcanized, and what happens during that process.

Rubber gets stronger, more flexible, and more durable after vulcanization. During this process, carbon chains get crosslinked.

Identify some of the general principles and guidelines that apply specifically to automated assembly.

Some of the principles and guidelines that apply specifically to automated assembly include the following: (1) Use modularity in product design. Each module to be produced on a single assembly system should have a maximum of 12 or 13 parts and should be designed around a base part to which other components are added. (2) Reduce the need for multiple components to be handled at once. (3) Limit the required directions of access. The ideal is for all components to be added vertically from above. (4) Use only high quality components. Poor quality components cause jams in feeding and assembly mechanisms. (5) Use snap fit assembly to eliminate the need for threaded fasteners.

What is thermal spraying?

Spraying molten coating materials onto substrate, where they solidify and adhere to surface

What is sticking friction in metalworking?

Sticking friction is when the work surface adheres to the surface of the tool rather than slides against it; it occurs when the friction stress is greater than the shear flow stress of the metal. It is generally associated with hot working.

What is "tempered" glass and why is glass tempered?

Tempered glass is heat-treated to put the outer surfaces into compression and the interior into tension. Glass is tempered so that if it breaks, it crumbles into small, relatively harmless pieces instead of shattering into dangerous, stabby shards.

What are some of the methods used to cure adhesives?

The curing methods include (1) chemical reaction between two components of the adhesive (e.g., epoxies), (2) heating of the adhesive, (3) use of ultraviolet light, and (4) application of pressure.

What happens to a ceramic material as it is sintered?

The individual particles bond together.

Why is a car frame made out of steel?

The steel is strong, though, form-able; but still can resist high impacts.

What is it meant by the term castability what factors if depend on?

The term castability refers to the ease with which a cast part can be produced. It depends on (1) the part design, (2) the metal used for the casting, and (3) the proper selection of casting process to economically satisfy production requirements.

What are ceramic insulators good for?

They are good for thermal and electrical insulation.

Why are thermo-plastics good for single-use consumer products such as soda bottles.?

They are inexpensive, light weight, easy to manufacture in mass.

why are thermoset plastics good for pot handles?

They do not melt, low thermal conductivity.

What is torque-turn tightening?

Torque-turn tightening involves the tightening of the threaded fastener to a certain low torque level, and then advancing the fastener by a specified additional amount of turn (e.g., a quarter turn).

What is the difference between traditional ceramics and new ceramics?

Traditional ceramics use natural clays and water; new ceramics use synthesized materials and may use a different liquid.

Electroless plating can be used on both metallic and nonmetallic substrates: (a) True or (b) false?

True

Explain why carbon black is added to rubber to make tires.

UV protection, increased strength.

What is annealing?

When glass/metal is heated until they are red hot and then cooled slowly.

What is the water atomization process?

When molten metal is falling through air and then sprayed with high velocity water which breaks up the metal and rapidly cools the metal.

Which three of the following are classified as fusion welding processes: (a) arc welding, (b) diffusion welding, (c) friction welding, (d) electron-beam welding, (e) resistance welding, and (f) ultrasonic welding?

a) arc welding (d) electron-beam welding (e) resistance welding

What is the difference between alloy and pure metal solidification?

alloys solidify at different temps. Have a liquidus and solidus . Pure metals solidify at same temp. they only have one point of liquid or solid.

As the arc-on time in arc welding increases, the cost of electric power in the welding operation becomes (a) less significant or (b) more significant?

b) more significant?

Define casting as a manufacturing process?

casting is a manufacturing process in which metal flows by gravity or other force into a mold where it solidifies in the shape of the mold cavity.

Wave soldering is used in the production of which one of the following products and/or assemblies: (a) beach balls, (b) children's toys, (c) plumbing fixtures, (d) printed circuit board assemblies, (e) surfboards, or (f) twisted wires?

d) printed circuit board assemblies,

Steel car bodies are commonly conversion coated with which one of the following thin films in preparation for painting: (a) carbonate, (b) chromate, (c) nitride, (d) oxide, (e) phosphate, (f)silicate, and (g) sulfate?

e. Phosphate

What is a common feature of a solidification processes?

starting material is either liquid or in a highly plastic condition. And the part is created by solidification of the material.

Why is titanium used in rocket components?

strong, lightweight, high strength to weight ratio

why is Pyrex good for chemistry labs?

the same as bake wear plus, low reactivity, optically clear, low coefficient of thermal expansion, easy to clean because non porous.

What are all the joining processes?

welding, brazing, soldering, and adhesive bonding

What are the Chemical cleaning Processes?

• Alkaline cleaning-most widely used - alkaline solution (NaOH) • Emulsion cleaning- soaps • Solvent cleaning- dissolves soils • Acid cleaning- Acids are sprayed on • Ultrasonic cleaning- Cavitation on part