joining q142

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(1) Which of the following are often manufactured as joined assemblies of two or more

component pieces?

(a) Large size products.(b) Products with a high degree of shape complexity

(c ) Products with a wide variation in required properties.

(d) All of the above.(e) a & c

(2) The ideal metallurgical bond, for which there would be no noticeable or detectable

interface, would require:(a) Perfectly smooth, flat, or matching surfaces.

(b) Surfaces that are clean and free from oxides, absorbed gases, grease, and other

contaminants.

(c) Metals with no internal impurities.(d) The joining of single crystals with identical crystallographic structure and

orientation.

(e) All of the above.

(3) Many of the problems that are inherent to welding and joining can be avoided byselecting the

(a) Proper process and considering both general and process-specific characteristicsand requirements.

(b) Proper design of the joint is extremely critical. Heating, melting, and

resolidification can produce drastic changes in the properties of base and fillermaterials.

(c) Weld metal properties can also be changed by dilution of the filler by melted

base metal, vaporization of various alloy elements, and gas-metal reactions.

(d) All of the above.(e) a & c only.

(4) To produce a high-quality weld, we will need :(a) a source of satisfactory heat and/or pressure.(b) a means of protecting or cleaning the metals to be joined.

(c) caution to avoid, or compensate for, harmful metallurgical effects.

(d) all of the above(e) a & b only.

(5) Various types of weld defects can also be produced. These include:(a) cracks in various forms.(b) cavities (both gas and shrinkage),(c) incomplete fusionbetween the weld and base metals,(d) incomplete penetration(insufficient weld depth),(e) all of the above.

( 6) Which of the following statement(s) is (are) true.

(a) One very important fact is that welding produces monolithic, or one-piece,

structures.When two pieces are welded together, they become one continuouspiece.

(b) When two pieces are welded, a crack in one piece of a multiplied structure may

not be catastrophic, because it will seldom progress beyond the single piece in

which it occurs.

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(c) Both of the above. (d) Non of the above

(7 ) Which of the following statement(s) is (are) true.(a) It is important to note that in welding a given material in small pieces may not

behave as it does in a larger size.

(b) In the form of a small Charpy bar. the material in small pieces exhibit ductilebehavior and good energy absorption at temperatures down to 25F(4C)

(c ) When small pieces are welded into a large structure, however, brittle behavior is

observed at temperatures as high as 110F (43C).(d) All of the above.

(e) a & c

( 8) Common error is to make welded structures too rigid, thereby restricting their

ability to redistribute high stresses and avoid failure.a. True b. False

(9) The grain structure in the fusion one may be:

(a) Fine or coarse,

(b) Equiaxed or dendritic,(c ) The grain structure in the fusion depends upon the type and volume of weld

metal and the rate of cooling.(d) All of the above.

(e) a & b

(10) Most electrode and filler rod compositions tend to produce fine, equiaxed grains.a. True b. False

(11) Associated with the conditions of fusion welding may be the:

a. entrapment of dissolved gases.

b. chemical segregation.c. grain size variation, grain shape problems.

d. orientation effects.

e. all of the above(12 ) In fusion welding the cooling rate would otherwise be extremely rapid unless the

following is (are) preheated

a. alloy steels.b. thicker sections.

c. high-thermal-conductivity metals, such as copper and aluminum.

d. All of above

e. a & c(13) The effects of thermal stresses can be reduced if the following suggestion(s) is

(are) , observed:

a. Total heat input to the weld should be minimized. Welds should he made withthe least amount of weld metal necessary to form the joint

b. Overwelding is not an asset, since it actually increases residual stresses and

distortion.c. Faster welding speeds reduce the welding time and also reduce the volume of

metal that is heated.

(d) All of the above. (e) a & b

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(14) Cold welding is affected by:

(a) The breakup of oxides at contacting surfaces.

(b) Applied pressure.(c) Contact between crystalline planes at interface.

(d) All of the above.

(15) Fluxes are often employed to:(a) Remove oxides.

(b) Form a shield that protects the weld from the atmosphere.

(c) Retard fast cooling.(d) All of the above.

(16) Of the following processes, which one will produce the largest HAZ:(a). Laser welding

(b) Electron beam welding

(c) Gas tungsten arc welding

(d) They are all about the same

(17) Brazing is used for:(a) The assembly of radiators and heat exchangers.

(b) The repair of casting.(c) None of the above.

(d) Answers (a) and (b)(18) Oxyacetylene torch offers the following advantage (s):

(a) Can be used for cutting as well as welding.

(b) wide range of metals can be welded.(c) Inexpensive and requires little maintenance.

(d) can be controlled easily

(e) All of the above.(19) Neutral Oxyacetylene torch

(a) O2:C2H2 ratio is 1-1.15:1

(b) good for welding of copper alloys(c) harmful for welding steels

(d) all of the above(20) The hottest flame in oxyfuel welding will be

a. Carburizing flame. b. Neutral flame

a. Oxidizing flame

d. They all reach the same peak temperature

(21) A joint is considered brazed rather than soldered when performed above whichtemperature?

a. 230oC/450oF

b. 270oC/520oF

c. 450o

C/840o

Fd. 520oC/970oF

e. 840oC/1540oF

(22) Oxyfuel cutting works best on metals that:(a) oxidize readily.

(b) do not have high thermal conductivity.

(c) answers (a) and (b).(d) none of the above

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(23) With Oxyfuel cutting

(a) carbon and low alloy steels readily cut.(b) stainless steels and cast iron require special techniques.

(c) aluminium and copers are difficult to cut.

(d) all of the above.(24) In cladding:

a. Portions of one sheet is coated with a material that prevents bonding.

b. And then roll bonding with another sheet, products can be made that are bonded only in

selected regions.

c. The no-bond region is then expanded, the expanded regions can form flow channels for

fluids.

d. All of the above

e. a and b only.

(25) Oxyfuel welding of cast iron is recommended:

(a) with cast iron filler rods.(b) braze welding is recommended if there are no corrosion objections.

(c) both (a) and (b).

(d) none of the above(26) Oxyfuel welding is not recommended for:

(a) Titanium.

(b) Metal to nonmetal.

(c) both (a) and (b).(d) lead and zinc

(e) all of the above

(27) Shielded metal arc welding(SMAW) is(a) the most common of the arc welding processes.

(b) has wide versatility.

(c) requires only low cost equipments(d) all of the above

(28) Electrode coatings perform the following functions:

(a) Stabilizing the arc. (b) Removing oxides and impurities(c) Accelerating the rate of cooling. (d) Answers (a) and (b).

(29) In GTAW the best deposition rate is obtained:(a) cold filler wire .

(b) hot filler wire.(c) hot filler wire with oscillation.

(d) cold filler wire with oscillation

(e) none of the above(30) The bonding strength of a brazed joint is enhanced by :

(a) clean surfaces.

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(b) proper clearance ideal .020 to .050 thousandth of an inch

(c) good fluidity and good wetting

(d) all of the above(e) (a) & (c) only

(31) GTAW:

(a) All metals and alloys can be welded.(b) use of inert gas makes it particularly useful to reactive metals like Aluminum and

Titanium.

(c) use of inert gas makes it particularly useful to refractory metals.(d) all of the above.

(32) Gas Metal Arc Welding:

(a) is fast and economical.

(b) no frequent change of electrode as in shielded arc welding.(c) no flux no slug

(d) light weight and readily automated.

(e) all of the above.

(33) Submerged arc welding(a) for making flat butt or fillet welds in low carbon steels.

(b) with some preheat and post heat precautions medium carbon and alloy steels canbe welded.

(c) submerged arc welding is not recommended for aluminum or magnesium..

(d) all of the above.(34) In Resistance Welding the sequence is observed:

(a) Current is applied to heat junction then pressure is applied to affect weld.

(b) There should be an adjustable delay after pressure has been applies until the weld

is started, only then current is turned on and held for some time. Pressure ismaintained until the end.

(c) Holding pressure is applied first and when voltage is applied for a preset period.

Voltage is lifted pressure is increased and maintained at higher level. For a shortperiod lower voltage is applied then both are lifted once welding sets in.

(d) None of the above possible.

(35) Examples of autogenous welding include:

a. SMAW

b. GMAW

c. Laser d. SAW

(36) Examples of autogenous welding include:

e. Resistance weldingf. GMAW

g. SMAW

h. FCAW(37) Projection welding is used in the following cases:

(a) Welding sheet metal

(b) Cross Wire welding

(c) Parts where the ridges are produced by machining.

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(38) Successful Cold welding requires

(a) heating. (b) very clean surfaces.(c) parts to be joined need be small soft and ductile

(d) all of the above. (e) (c) and (b) only.

(39) Ultrasonic welding(a) is restricted to butt joints.

(b) is restricted to joining thin materials.

(c) best for aluminum and copper(d) all of the above

(e) (c) and (b) only

(40) Successful Diffusion welding requires.

(a) cryogenic temperature.(b) parts to be joined need be of the same metal

(c) prepared surfaces are maintained in contact under sufficient pressure

(d) all of the above. (e) (c) and (b) only.

(41) Explosive welding is used for(a) bonding of corrosion-resistance metal to heavier plate.

(b) used for dissimilar metals.(c) all of the above. (d) none of the above.

(42) When metals of different thickness or different conductivities are to be welded, they can

generally be brought to the proper temperature in a simultaneous manner by:(a) using a larger electrode or

(b) One with higher conductivity against the thicker or higher-resistance material.

(c) all of the above (d) none of the above.

(43) The following plastics can be welded(a) thermoplastics. (b) thermosetting plastics.

(c) thermoelectro plastics

(d) (a) and (b) only. (d) none of the above.(44) Plastic welding methods are divided into

(a) those which utilizes mechanical and friction to generate heat.

(b) those which involve external heat source such as hot plate.(c) those which involve addition of certain type of fillers giving rise to exothermic

reactions

(d) all of the above (e) (a) and (b) only.

(45) Which of the following is not a reason for using mechanical assembly?a. No heat affected zone in the base parts

b. Ease of assembly

c. Involves melting of the base part(46) Carbon and low alloy steel Brazing

(a) is recommended for low and medium carbon steels.

(b) difficult for high carbon steels.(c) seldom used for heat treated alloy steels

(d) All of the above. (e) (a) and (b) only

(47) The grain structure in the fusion one may be fine or coarse, equiaxed or dendritic,

depending upon the:

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(a) type and volume of weld metal.

(b) the rate of cooling.

(c) most electrode and filler rod compositions tend to produce fine, equiaxed grains.(d) all of the above is true. e. a&b only.

(48) The pool of molten metal created by fusion welding is prone to all of the problems and

defects associated with metal casting, such as(a) gas porosity, blowholes. (b) inclusions,

(b) cracks, and shrinkage.

(c) all of the above is true (e) a&b only(50) Since the amount of molten metal in fusion welding is usually small compared to the

total mass of the workpiece. rapid solidification and rapid cooling of the solidified metal

are quite common. Associated with these conditions may be the :

a. entrapment of dissolved gases. b. chemical segregation.c. grain size variation, grain shape problems. d. orientation effects.

e. all of the above.

(51) The following are among the advantages of brazing:

(a) virtually all metals can be joined.(b) ideal for dissimilar materials

(c) thinner more complex can be accomplished(d) all of the above (e) (a) & (b) only

(52) The following are among the advantages of brazing:

(a) less heating is required to affect the joint.(b) smaller heat affected zone

(c) highly adaptable to automate

(d) all of the above (e) (a) & (b) only.

(53) The following are among the disadvantages of brazing:(a) subsequent heating will adversely affect the joint.

(b) the joint is more susceptible to corrosion

(c) both of the above (d) none of the above.(54) Preheating is more common with:

a. alloy steels. b. thicker sections.

c. it is particularly important with the high-thermal-conductivity metals, such ascopper and aluminum, where the cooling rate would otherwise be extremely rapid

d. all of the above. e. a & c only

(54) Thermal Effects In Brazing And Soldering

(a) Intermetallic phases can form at the interface and alter the properties of the joint.If present in small amounts, they can enhance bonding and provide strength

reinforcement.

(b) Most intermetallic compounds, however, are quite brittle. Too muchintermetallic material can result in significant loss of both strength and ductility.

(c) Both of the above are true. (d) None of the above is true.

(55) Underwater welding is also known as submerged arc weldinga. True b. False

(56) Which of the following applies to the weld metal in gas metal arc welding:

(a) Same microstructure as base metal

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(b) Same composition as base metal

(c) Loss of alloying elements is possible

(d) Lower heat input than laser welding.(57) What potential changes can be expected in the HAZ of a cold rolled low carbon steel?

(a) Martensitic transformation

(b) Recrystallization(c) Precipitation

(d) None of the above

(58) What potential changes can be expected in HAZ of an annealed High Carbon Steel?(a) Martensitic transformation

(b) Recrystallization

(c) Precipitation

(d) None of the above(59) The following suggestions can help reduce distortion or warping of the assembly.

a. Total heat input to the weld should be minimized. Welds should he made with

the least amount of weld metal necessary to form the joint

b. Overwelding is not an asset, since it actually increases residual stresses anddistortion.

c. Faster welding speeds reduce the welding time and also reduce the volume ofmetal that is heated.

d. all of the above e. only a &c

(60) What is a plug weld used for?a. To weld two pieces of material by melting through one of them to the other

b. To seal off the end of pipes

c. To make watertight welds

(61) Which of the following weld type(s) is used to improve the wear resistance of a metalcomponent:

a. Butt weld only

b. Butt weld and lap weld onlyc. Butt weld, lap weld, and surface bead weld

d. Lap weld and surface bead weld only

e. Surface bead weld only(62) Which are potential problems of welds:

a. Changes in properties of base and weld metal

b. Residual electric and magnetic charges due to the use of some electric (arc,

resistance) processesc. Vaporization of some alloying elements under the extreme heat of some

processes

d. All of the above. e.Only a and c(63) Which of the following is NOT a potential weld problem:

a. Metallurgical changes. b. Excessive distortion

b. Residual magnetic charges due to the use of some electric processesc. Shrinkage cavities

d. All are potential weld problems

(64) Surfacing/bead welds are often use to:

a. Replace broken chips of the surface of a part

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b. Cover the surface of a part of with a stronger material

c. Both a and b d. None of the above

(65) Groove welds are performed to assure:a. Proper edge preparation

b. Full penetration of weld

c. Metallurgical changes of weldd. Lower residual stresses on the weld

e. To eliminate cracks in welds

(66) Thermal spray coatings

a. Add little, if any, additional strength to a part, since the strength of the porous coating is

usually between one-third and one-half of its normal wrought strength.

b. The coating to provide resistance to heat, wear, erosion, and/or corrosion.

c. The coating to restore worn parts to original dimensions and specifications.

d. All of the above e. a & c only.

(67) The ideal adhesive

a. bonds to any material.

b. needs no surface preparation.

c. cures rapidly.

d. and maintains a high bond strength under all operating conditions.

e. All of the above

(68) Structural adhesives are bonding materials that can be stressed to a high percentage of

their maximum load for extended periods of time without failure.

a. True b. False

(69) The HAZ will NOT experience which of the following:

a. Transformation

b. Recrystallizationc. Incipient fusion

d. Crackinge. Embrittlement

(70) Of the following processes, which one will produce the largest HAZ:

a. Laser welding. b. Spot welding

c. Electron beam welding. d. Gas tungsten arc weldinge. They are all about the same

(71) Of the following processes, which one will produce the smallest HAZ:

a. Gas Metal arc welding. b. Spot welding

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c. Shielded metal arc welding. d. Gas tungsten arc welding

e. Submerged arc welding

(72) Which of the following can be used to limit the HAZ formation:a. Cold working the parts prior to welding

b. Post weld heat treatment

c. Pre weld heat treatmentd. All of the above. Only b and c

(73) Which of the following CANNOT be used to limit the HAZ formation:

a. Preheatingb. High heat input welding process

c. Using a fillet vs. a butt weld

d. Flux and slag additions to assist with HAZ prevention

e. All of the above can be used to limit HAZ formation.(74). The reason(s)for the commercial importance of powder metallurgy is /are

a. parts can be made to net or near net shape,

b. parts can be made with a controlled level of porosity,

c. certain metals difficult to process by other methods can be processed by PMd. PM allows the formulation of unusual alloys not easily obtained by traditional

alloying methods.e. All of the above

(75). What is (are) some of the disadvantage(s) of PM methods?

a. high tooling costs,b. metal powders are expensive,

c. difficulties in storing and handling,

d. certain limitations on part geometry imposed by the uniaxial press methods,

e. all of the above(76). The method most widely used to produce metallic powders?

a. atomization - the conversion of molten metal into droplets which solidify into

powdersb. chemical reduction - reducing metallic oxides by use of reducing agents

which combine with the oxygen to free the metals in the form of powders

c.electrolysis - use of an electrolytic cell to deposit particles of the metal onto thecathode in the cell.

d. All of the above e. (a) & (b) only

(77). The basic steps in the conventional powder metallurgy shaping process?

(a) powder preparation (b) pressing, (c) sintering. (d) all of the preceding(78). The technical difference between mixing and blending in powder metallurgy?

(a) Mixing refers to the combining of metal powders of different chemistries

(b) while blending means combining particles of the same chemistry but differentsizes.

(c) both of the above

(d) none of the above(79) Which of the following most closely typifies the sintering temperatures in PM?

(a) 0.5mpt, (b) 0.8 mpt, (c) 1.0 mpt (d) 1.1 mpt.

(80). The typical steps in the sintering cycle in PM are

a. preheat, in which lubricants and binders are burned off,

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b. sintering,

c. post press

d. cool downe a, b & d

(81). Infiltration in PM when used is to

a. is to precipitate a nonporous structure,b. is to improved toughness and strength.

c. Both of the above

d. None of the above(82). As particle size increases, interparticle friction

(a) increases, (b) decreases.

(83). Impregnation refers to which of the following (may be more than one)?

a. soaking oil by capillary action into the pores of a PM part,b. putting polymers into the pores of a PM part, or

c. filling the pores of the PM part with a molten metal.

d. a & b

e. a & c(84). In cold isostatic pressing, the mold is most typically made of which of the following?

(a) rubber, (b) sheet metal, (c) tool steel, (d) textile, (e) thermosetting polymer.(85). Which of the following processes combines pressing and sintering of the metal powders

(may be more than one

(a) hot pressing,(b) spark sintering,

(c) hot isostatic pressing.

(d) all of the above

(86). Which of the following design features would be difficult or impossible to achieve byconventional uniaxial pressing and sintering ?

a. holes along the direction of pressing

b. threaded holesc. outside rounded corners,

d. all of the above e. b & c

(87) 60% to 70% of commercial metal powder is produced in the USA are of the followingtype:

(a) slow rate cooling of molten metal

(b) cooling rate of 102 Co/sec

(c ) cooling rate 106 Co/sec(d) none of the above

(88). Metal powder form is:

a. Higher in cost than solid form.b. Adaptable to mass production

c. Expensive dies.

d. All of the above. e. None of the above.(89). Particle sizedistribution has a considerable influence in determining

a. Flowability. b. Apparent density.

c. Final porosity of the product. d. Final strength

e. All of the above.

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(90). The Isostatic process has the following advantages:

a. Uniform density and strength. b. Low cost of equipment.

c. Higher green compact strength.d. All of the above. e. None of the above.

(91). Powder metallurgy products include:

a. Cemented carbides, porous bearing, and metallic powders.b. Gears and Pump Rotors, motor brushes.

c. Magnets, contact parts.

d. All of the above. e. None of the above.(92). If cooling rate approaches 106 Co metals can solidify without becoming crystalline.

Such structures enjoy:

a. Modest strength

b. Improved corrosion resistancec. 60% to 70% of Powder metals in the USA are of this type

d. (a) & (b) e. (b) & (c)

(93). Powder metallurgy is most economics for

a. small batch size production. b. medium batch size productionc. large batch size

d. any of the above.(93) Which of the following could not be descried as a products made by powder metal:

a. gears, cams. b. balls for ball point pens.

c. brake pads.d. all of the above. e. none of the above.

(94) When cooling is slow (such as in gas atomization) and surface tension is high,

a. smooth-surface spheres can form before solidification.

b. with more rapid cooling of water atomization, irregular shapes tend to beproduced.

c. both of the above. d. none of the above.

(95) Which of the following statement(s) is true ?a. increasing the cooling rate of an atomized liquid can result in the formation of an

ultra-fine or microcrystalline grain size.

b. where a large percentage of the atoms are located in grain boundary regions,giving unusual properties such as high diffusivity, expanded alloy possibilities,

and good formability.


(96) Which of the following statement(s) is(are) true ?a. In powder products, the final chemistry is often obtained by combining pure

metal or nonmetal powders , rather than starting with prealloyed materials.

b. It is most likely that the starting material will be a mixture of various grades or sizesof powder, powder of different compositions, along with addition of lubricants or

binders.

c. both of the above. d. none of the above.(97) Blending is restricted to particles of the same composition but of different particle sizes

to control porosity.

a. true b. false.

(98) Which of the following statement(s) is(are) true ?

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a. Lubricants such as graphite and stearic acid improve the flow characteristics and

compressibility at the expense of green strength.

b. Binders produce the reverse effect.c. both of the above. d. none of the above.

(99) Density distribution in the green compact is dependent on :

a. how pressure is appliedb. the direction of the applied pressure.


(100) For canning in Hot Isostatics the following have been used:a. Sheet metal b. glass c. ceramics.

d. all of the above. e. none of the above

101 In friction welding, no special preparation of the joint is necessary.a. True b. False

102 Autogenous welding uses a filler material.a. True b. False

103 In resistance Butt-welding there may be some upsetting of the joint

a. True b. False

104 MIG is faster than TIG.

a. True b. False

105 Electroslag is most suitable for welding of sheet metala. True b. False

106 It is not safe to store Acetylene (on its own) at pressure much higher than 15 psi.

a. True b. False

107. Oxidizing flame has the widest application in oxyacetylene welding.

a. True b. False

108 Reducing oxyacetylene torch is used in welding of Monel Metal, nickel and certain alloy

of steels.a. True b. False

109 Reducing flame has three regions instead of the two in neutral and oxidizing.

a. True b. False

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110. Since the penetration depth is limited, bead welds are used primarily for(a) joining thin sheets of metal,

(b) building up surfaces, and

(c) depositing hard-facing (wear-resistant) materials.(d) All of the above.

(e) a & c

111. The specific type of groove usually depends upona. the thickness of the joint,

b. the welding process to be employed,

c. the position of the work


112. Silver brazing alloys are used for joining

(a) various ferrous metals.

(b) non ferrous materials.(c) non ferrous except aluminum and magnesium

(d) (a) and (b) only(e) (a) and (c) only

113. gold based brazing alloys are used for joining

(a) iron. (b) nickel. (c) cobalt

(d) all of the above (e) (a) and (c) only

114. Compared to a base metal a brazed joint has:

(a) lower melting point.

(b) lower strength.(c) different composition from base metal.


115. Oxyhydrogen flame adjustment is much easier than that of oxyacetylene torch.

a. True b. False

116. Aluminum is spot weldable to

(a) Tin plate.

(b) Zinc.

(c) Brass(d) (a) and (b)

(e) all of the above

117. Steel is spot weldable to(a) Brass.

(b) Tin plate.

(c) Zinc(d) all of the above

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(e) (a) and (b) only.

118. The primary limitation/s to the use of resistance welding is /are:

a. the high initial cost of the equipment,

b. limitations to the type of joints that can be made,

c. skilled maintenance personnel are required to service the control

equipment, and

d. some materials require special surface preparation prior to welding.


119. Because of the rapid heat inputs, short welding times, and rapid quenching

by both the base metal and the electrodes,

a. The cooling rates in spot welds can be extremely high.

b. In medium-and high-carbon steels, martensite can readily form.

c. A post-weld heating is generally required to temper the weld.

d. All of the above

e. a and b only

120. Coalescence is produced in cold welding

a. by only the application of pressure.

b. No heating is used,

c. the weld resulting from localized pressures that produce 30 to 50% cold

deformation. .

d. All of the above

e. a and b only

121. In cladding:

f. Portions of one sheet is coated with a material that prevents bonding.

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g. And then roll bonding with another sheet, products can be made that are

bonded only in selected regions.

h. The no-bond region is then expanded, the expanded regions can form flow

channels for fluids.

i. All of the above

j. a and b only.

122. Inertia welding differs from friction welding in that

a. the moving piece is attached to a rotating flywheel. The flywheel is brought

to speed, separated from the driving motor, and the rotating assembly is

pressed against the stationary

member.

b. The kinetic energy is converted to heat during the deceleration..

c. Both of the above.

d. None of the above

123. In the friction and inertia welding processes, surface impurities tend to

be displaced radially into a small upset flash that can be removed after

welding, if desired.

a. True b. False

124. Friction and inertia welding is restricted to:

a. joining round bars or tubes of the same size,

b. connecting bars or tubes to flat surfaces.

c. The ends of the workpieces must be cut true and be fairly smooth.

d. All of the above

e. a and b only.

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125. Ultrasonic welding is restricted to:

a. the joining of thin materials, such as sheet, foil, and wire.

b. the attaching of thin sheets to heavier structural materials.


d. None of the above.

126. Concerning Ultrasonic Welding which of the following is true:

a. Ultrasonic welding can be used to join a number of metals and dissimilar

metal combinations (even metals to nonmetals).

b. Since temperatures are low, the process is an attractive one for heat-

sensitive materials.

c. The equipment is simple and reliable, and only moderate operator skill is

required.

d. Surface preparation and energy requirements are less than for competing

processes.

e. All of the above

126. Diffusion welding is a solid state bonding that occurs when properly

prepared surfaces are maintained in contact:

a. under pressure and

b. time at elevated temperature.

c. Quality of the bond is highly dependent upon surface preparation.

d. All of the above

e. a and b only

130. In electroslag welding heat is derived from the passage of electrical

current through a liquid slag. Resistance heating within the slag causes the

temperature increase.

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a. True b. False

131. Electroslag welding:

a. is most commonly used to vertical or circumferential joints because of theneed to contain the pool of

molten slag.

b. The process is particularly attractive for the joining of thick plates (up to 36-

inches thick).


d. None of the above.

131. Thermal spray coatings

e. add little, if any, additional strength to a part, since the strength of the

porous coating is usually between one-third and one-half of its normal

wrought strength.Applications, therefore, generally look to the coating toprovide.

f. resistance to heat, wear, erosion, and/or corrosion.

g. or to restore worn parts to original dimensions and specifications.

131. The ideal adhesive

f. bonds to any material.

g. needs no surface preparation.

h. cures rapidly.

i. and maintains a high bond strength under all operating conditions.

j. All of the above

132. Structural adhesives are bonding materials that can be stressed to a

high percentage of their maximum load for extended periods of time

without failure.

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133. True b. False

134. Curing of the structural adhesives can be performed by the use of:

a. heat

b. radiation or light (photoinitiation)

c. Moisture

d. Activators ,catalysts, multiple-component reactions or combinations thereof.

e. All of the above

135.Possible additives to epoxy adhesives include:

a. accelerators (to speed the cure rate)

b. plasticizers (to add flexibility, peel resistance or impact resistance).

c. fillers (to add bulk and reduce cost).

d. All of the above

e. a and b only

136. Silicone Adhesives enjoy the following attributes:

a. The silicone adhesives form low-strength joints, but can withstand

considerable expansion or contraction.

b. Flexibility and sealing ability are other attractive properties.

c. Numerous materials can be bonded, and the bonds resist moisture, hot

water, oxidation, and weathering, and retain their flexibility at low

temperatures.

d. All of the above

e. b and c only.

137. On joints bonded by adhesives

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a. The stress state in a bonded joint can be tension, shear, cleavage, or peel.

b. Since most adhesives are much weaker in peel and cleavage, joints should

be either shear or tension.

c. Looking further, the shear strengths are greater than the tensile strengths,

so the best adhesive joint would be one in which the stress state is pure

shear.

d. All of the above

e. a and c only.

138. With discrete fasteners, the stress distribution is extremely non

uniform, with much of the load concentrated on the fasteners. With

adhesive joints, the load is distributed uniformly over the entire area of thejoint.

a. True b. False

139. The most common causes for the failure of mechanically fastened

joints relate to:

a. joint preparation.

b. fastener installation

c. both of above

d. none of the above.

140. Fastener areas of concern:

a. Hole manufacture and alignment,

b. Installation with too much or too little preload,

c. misalignment of surfaces.

d. insufficient area under load-bearing heads, vibrations that can lead to

further loosening of the joint (and fastener fatigue)


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(141) Welding can be accomplished by the use of:a. Heat only

b. Pressure only

c. Both heat and pressure combined

d. All of the above

(142) Underwater cutting torches uses hydrogen for preheating flame because:

(a) Hydrogen provides more uniform heating.

(b) Hydrogen provides more intense heating.

(c) Acetylene gas is not safe to use under the high pressure.(d) None of the above.

joining q142

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