McqMate
| 101. |
What is the function of flux in submerged arc welding? |
| A. | to completely cover the welded zone |
| B. | to prevent oxidation of joint |
| C. | to prevent spattering of molten metal |
| D. | to prevent sticking of molten metal |
| Answer» D. to prevent sticking of molten metal | |
| Explanation: flux is used to completely | |
| 102. |
If the heat transfer efficiency is 0.5 and the melting efficiency is 0.6, then the overall efficiency will be? |
| A. | 0.83 |
| B. | 0.03 |
| C. | 0.30 |
| D. | 0.12 |
| Answer» C. 0.30 | |
| Explanation: ηtotal = ηmelting * ηheat transfer, where η denotes efficiency. there are two types of efficiencies, one is melting efficiency and another is heat transfer efficiency. | |
| 103. |
The deflection of the arc in arc blow is by? |
| A. | electric field |
| B. | magnetic field |
| C. | combination of both |
| D. | hydrostatic field |
| Answer» B. magnetic field | |
| Explanation: the deflection of the arc in arc blow is by a magnetic field. electric field, hydrostatic field does not affect the deflection of the arc. | |
| 104. |
If the total efficiency is 0.35 in arc welding. Then what is the welding speed in mm/sec if the cross-sectional area is 5mm2, welding power is 2 kW and the heat required in melting the metal is 100 J/mm3. |
| A. | 1.4 |
| B. | 14 |
| C. | 1400 |
| D. | 140 |
| Answer» A. 1.4 | |
| Explanation: n = (p×total efficiency)/(q×a), where p represents power, q represents heat transfer, and a represents the cross-sectional area. | |
| 105. |
Which of the following gas welding process uses constant voltage? |
| A. | submerged arc welding |
| B. | tungsten inert gas welding |
| C. | stud welding |
| D. | gas metal arc welding |
| Answer» D. gas metal arc welding | |
| Explanation: gas metal arc welding uses constant voltage. tungsten inert gas welding does not use constant circuit voltage. | |
| 106. |
In order to prevent oxidation and retain molten metal in stud welding which of the following is used? |
| A. | ceramic rings |
| B. | metal rings |
| C. | non-metal rings |
| D. | flux |
| Answer» A. ceramic rings | |
| Explanation: in order to prevent oxidation and retain molten metal in stud welding ceramic rings are used. | |
| 107. |
Which of the following parameters control the quality of weld? |
| A. | composition of electrode |
| B. | size of electrode |
| C. | size of metal plate |
| D. | composition of metal plate |
| Answer» B. size of electrode | |
| Explanation: the parameters control the quality of weld are size of electrode and the current that produces sufficient heat to melt the base metal and minimizes electrode splatter. | |
| 108. |
Which of the following can be non-low hydrogen process? |
| A. | shielded metal arc welding |
| B. | submerged arc welding |
| C. | gas-shielded metal arc welding |
| D. | flux core arc welding |
| Answer» A. shielded metal arc welding | |
| Explanation: shielded metal arc welding can be a low hydrogen process or non-low hydrogen process, while submerged arc welding, gas-shielded metal arc welding, flux core arc welding are low hydrogen process. | |
| 109. |
Why hydrogen not used excessively for welding? |
| A. | increases welding rate |
| B. | decreases welding rate |
| C. | destroys the metal plate |
| D. | affects the weld |
| Answer» D. affects the weld | |
| Explanation: hydrogen causes weld to crack. hence most of the welding processes are low hydrogen welding process. | |
| 110. |
Which of the following is true about shielded metal arc welding? |
| A. | equipment cost is high |
| B. | cannot weld different types of metals |
| C. | cannot be used for metal sheets under 1.5mm thickness |
| D. | entire electrode can be used |
| Answer» C. cannot be used for metal sheets under 1.5mm thickness | |
| Explanation: the following are some | |
| 111. |
Which of the following is not correct about submerged arc welding? |
| A. | high deposition rate |
| B. | short set-up time |
| C. | high quality welds |
| D. | slag removal needed |
| Answer» B. short set-up time | |
| Explanation: the following are some advantages of submerged arc welding: (i) high deposition rate, (ii)high quality welds with good ductility, high impact strength, good corrosion resistance, (iii)good for welding long joints(in excess of 1m), (iv)no eye protection required. some disadvantages are : (i) long set-up time, (ii)slag removal needed, (iii)used for flat or horizontal fillets only. | |
| 112. |
Choose the correct option regarding metal- active gas welding? |
| A. | not suitable for thin metal sheets |
| B. | need to stop welding to change the consumed electrode |
| C. | equipment is not expensive |
| D. | high deposition rate |
| Answer» D. high deposition rate | |
| Explanation: gas-shielded metal arc welding is also called metal-active gas welding. the following are some advantages of gas- shielded metal arc welding : (i) suitable for metals as thin as 0.58mm, (ii)all welding positions can be used, (iii) no need to stop welding to change the consumed electrode, (iv)high deposition rates. some disadvantages are : (i)welding equipment is expensive and | |
| 113. |
What is the differentiating factor between flux core arc welding and gas-shielded metal arc welding processes? |
| A. | structure and chemical composition of electrode |
| B. | structure and chemical composition of metal plate |
| C. | time of welding |
| D. | process of welding |
| Answer» A. structure and chemical composition of electrode | |
| Explanation: the structure and chemical composition of electrode wire is the differentiating factor between flux core arc welding and gas-shielded metal arc welding processes. unlike gas-shielded metal arc welding, flux core arc welding electrode wire is not solid and consists of thin-walled metal tube filled with flux. | |
| 114. |
Which of the following is true about flux core arc welding? |
| A. | low deposition rate |
| B. | cannot weld narrow angles |
| C. | slag removal required |
| D. | generates less volume of fumes and smoke. |
| Answer» C. slag removal required | |
| Explanation: the following are some advantages of flux core arc welding: (i)high deposition rates, (ii)can be used to groove angles as narrow as 30˚, (iii)welds in all positions can be made, (iv)has excellent weld pool control. some disadvantages are: (i) slag removal required, (ii) generates large volume of fumes and smoke. | |
| 115. |
Which of the following welding process is preferred for field application? |
| A. | shielded metal arc welding |
| B. | submerged arc welding |
| C. | gas-shielded metal arc welding |
| D. | flux core arc welding |
| Answer» A. shielded metal arc welding | |
| Explanation: submerged arc welding, gas- shielded metal arc welding, flux core arc welding, electro slag welding can be used when welding is done in fabrication shop. for field applications, shielded metal arc welding is preferred. | |
| 116. |
Which of the following is not correct about electro slag welding? |
| A. | high deposition rates |
| B. | welds flat or vertical joints only |
| C. | multiple electrodes may not be used |
| D. | complicated set-up |
| Answer» C. multiple electrodes may not be used | |
| Explanation: the following are some advantages of electro slag welding: (i) high deposition rates, (ii) multiple electrodes may be used, (iii)low distortion. some disadvantages are: (i) welds flat or vertical joints only, (ii) complicated set-up, (iii)cooling water is needed. | |
| 117. |
Which of the following process does not have high deposition rate? |
| A. | shielded metal arc welding |
| B. | electro slag welding |
| C. | gas-shielded metal arc welding |
| D. | flux core arc welding |
| Answer» A. shielded metal arc welding | |
| Explanation: flux core arc welding, gas- shielded metal arc welding, electro slag welding have high deposition rates. | |
| 118. |
Which of the following can be easily be welded from flash butt welding process? |
| A. | tin |
| B. | lead |
| C. | cast irons |
| D. | carbon steel |
| Answer» D. carbon steel | |
| Explanation: in flash butt welding process, the welding of materials like steels and other iron alloys are easy to weld, except for cast iron. the welding of materials like tin, lead, zinc and antimony cannot be welded using flash butt method. | |
| 119. |
Electrodes used in spot welding are made up of which material? |
| A. | only copper |
| B. | copper and tungsten |
| C. | copper and chromium |
| D. | copper and aluminium |
| Answer» D. copper and aluminium | |
| Explanation: the electrodes that are employed in the spot welding are required to possess a high amount of electrical and thermal conductivity. hence, they are primarily made up of copper or copper and tungsten or copper and chromium. | |
| 120. |
Which of the following method is not used in applying pressure in spot welding process? |
| A. | hand lever |
| B. | foot lever |
| C. | air pressure |
| D. | hydraulic cylinder |
| Answer» A. hand lever | |
| Explanation: none. | |
| 121. |
What is the maximum power supply needed for the working of spot welding process? |
| A. | 135 kva |
| B. | 140 kva |
| C. | 145 kva |
| D. | 150 kva |
| Answer» D. 150 kva | |
| Explanation: spot welding can be used for all types of ductile metals. it can also be employed for structures of sheet metals, and can be applied for making of boxes and cans. for its applications, the maximum power that can be needed for this process is 150 kva. | |
| 122. |
What is the minimum power supply needed for the working of spot welding process? |
| A. | 10 kva |
| B. | 14 kva |
| C. | 6 kva |
| D. | 22 kva |
| Answer» A. 10 kva | |
| Explanation: none. | |
| 123. |
Upset butt welding is majorly used in the making of automobile parts. |
| A. | true |
| B. | false |
| Answer» B. false | |
| Explanation: upset butt welding is mainly used for the manufacture of welding bars, rods, wires or tubing. for the manufacture of automobile parts, such as axles, wheels or frames, flash butt welding is extensively used. | |
| 124. |
In friction welding process, materials are joined by motion between materials. |
| A. | rectilinear |
| B. | rubbing |
| C. | translatory |
| D. | brownian |
| Answer» B. rubbing | |
| Explanation: friction welding is a solid-state joining process that produces coalescence in materials, using the heat developed between surfaces through a combination of mechanically induced rubbing motion and applied load. the resulting joint is of forged quality. | |
| 125. |
All metallic engineering materials which are can be friction welded. |
| A. | soft |
| B. | weldable |
| C. | forgeable |
| D. | metamaterials |
| Answer» C. forgeable | |
| Explanation: as a rule, all metallic | |
| 126. |
Friction welding is process. |
| A. | costly |
| B. | cost saving |
| C. | time consuming |
| D. | highly material selective |
| Answer» B. cost saving | |
| Explanation: since dissimilar materials can be joined, a significant cost savings are possible because engineers can design bimetallic parts that use expensive materials only where needed. expensive forgings and castings can be replaced with less expensive forgings welded to bar stock, tubes, plates and the like. | |
| 127. |
Friction welding produces quality joints, with a 100% weld. |
| A. | lap joint |
| B. | tee-joint |
| C. | butt joint |
| D. | edge joint |
| Answer» C. butt joint | |
| Explanation: friction welding produces forged quality joints, with a 100% butt joint weld through the contact area. furthermore, in friction welding heat affected zone is much narrower as compared to other welds, which indeed reduces the cost of post-weld heat treatments (stress relieving processes). | |
| 128. |
Which of the following is not true about friction welding? |
| A. | dissimilar metals cannot be joined |
| B. | this technique is relatively faster as compared to the other techniques |
| C. | this technique is suitable for any parts of shape or size |
| D. | sheared surfaces can also be joined by the process |
| Answer» A. dissimilar metals cannot be joined | |
| Explanation: following are the few advantages of friction welding over other techniques: | |
| 129. |
Which of the following holds true for friction welding? |
| A. | hazardous fumes are generated during the process |
| B. | argon is used as a shielding gas |
| C. | it is a power consuming process |
| D. | there are no solidification defects in the welded parts |
| Answer» D. there are no solidification defects in the welded parts | |
| Explanation: following are the few reasons to consider friction welding over other techniques: | |
| 130. |
In inertia friction welding energy of welding machine is used. |
| A. | electrical |
| B. | potential |
| C. | rotational |
| D. | frictional |
| Answer» C. rotational | |
| Explanation: inertia friction welding is a variation of friction welding in which the energy required to make the weld is supplied primarily by the stored rotational kinetic energy of the welding machine. | |
| 131. |
Weld strength in inertia friction welding is more than direct drive friction welding. |
| A. | true |
| B. | false |
| Answer» A. true | |
| Explanation: inertia friction welding has the following advantages over the direct drive friction welding process: | |
| 132. |
In direct drive friction welding, lower weld forces are generated. |
| A. | true |
| B. | false |
| Answer» A. true | |
| Explanation: following are the advantages of direct drive friction welding over inertia friction welding: | |
| 133. |
Which of the following defects occur due to flux employed and electrode coating? |
| A. | inclusion of slag |
| B. | inadequate penetration |
| C. | incomplete fusion |
| D. | porosity |
| Answer» A. inclusion of slag | |
| Explanation: slag inclusions are one of the main weld defects. if we don’t properly clean the slag from a bead, we run the risk of it becoming part of the weld when we run the next bead. a good welder will generally burn it out on the next pass, but if not, there will be a chunk of slag in the bead which leaves a weak spot. slag inclusions. | |
| 134. |
Which of the following defects occur when the deposited metal is not focused on the root of weld? |
| A. | inclusion of slag |
| B. | inadequate penetration |
| C. | incomplete fusion |
| D. | porosity |
| Answer» B. inadequate penetration | |
| Explanation: inadequate penetration defects | |
| 135. |
Which of the following defects occur due to the entrapment of gas bubbles by the freezing dendrites during the cooling of molten pad? |
| A. | inclusion of slag |
| B. | inadequate penetration |
| C. | incomplete fusion |
| D. | porosity |
| Answer» D. porosity | |
| Explanation: referred to as worm holes, these are gas pockets trapped in the weld. a couple of reasons would be from not enough shielding gas in mig, or moisture in the flux. | |
| 136. |
Which of the following defects occur due to filler material having a different rate of contraction compared to parent metal? |
| A. | undercut |
| B. | spatter |
| C. | cracking in weld metal |
| D. | cold cracking |
| Answer» C. cracking in weld metal | |
| Explanation: weld cracking occurs close to the time of fabrication. most forms of cracking result from the shrinkage strains that occur as the weld metal cools. it can be of hot cracks types. | |
| 137. |
Which of the following defects occur due to scattering of metal around the vicinity of weld? |
| A. | undercut |
| B. | spatter |
| C. | cracking in weld metal |
| D. | cold cracking |
| Answer» B. spatter | |
| Explanation: spatters are the droplets of molten material during gas welding or arc welding. a temperature difference and slag accumulation are the reason of spatter formation. welding speed is also one of the main causes of spatter. type of material used and type of welding also decide to spatter density. | |
| 138. |
Which of the following defects occur due to incorrect welding techniques? |
| A. | undercut |
| B. | hot cracking |
| C. | cracking in weld metal |
| D. | cold cracking |
| Answer» C. cracking in weld metal | |
| Explanation: cracking in weld metal defect occur due to incorrect welding techniques. sometimes cracking may not be visible by naked eyes. | |
| 139. |
Which of the following defects occur at a lower temperature? |
| A. | undercut |
| B. | hot cracking |
| C. | cracking in weld metal |
| D. | cold cracking |
| Answer» D. cold cracking | |
| Explanation: cold cracks are those that occur after the weld metal has cooled to room temperature and may be hydrogen related. | |
| 140. |
Precision forging is a type of forging operation in which the metal stocks and dies are controlled very tightly. |
| A. | true |
| B. | false |
| Answer» A. true | |
| Explanation: in precision type forging operation, the volume of the metal stock and the dies are controlled very tightly. such operations are called as precision forging which is a modern technique of forging. | |
| 141. |
In open die forging process, homogenous deformation of billet has occurred with uniform increase in its diameter. |
| A. | true |
| B. | false |
| Answer» B. false | |
| Explanation: in open die forging process, the deformation is not homogenous as bulging occurs due to the presence of friction at the interface of die and billet. this friction opposes the motion of billet; this effect is generally called as barreling effect. | |
| 142. |
Isothermal forging is also known as cold forging operation. |
| A. | true |
| B. | false |
| Answer» B. false | |
| Explanation: isothermal forging is a hot forging operation in which the metal part is maintained at some high temperature. the forging dies are also maintained at the same high temperature. in this method, the metal flows readily that reduces the amount of force required. but this process is expensive than the conventional forging and mainly used for materials like titanium and super-alloys. | |
| 143. |
The metal forging operation can be performed manually or by automation. |
| A. | true |
| B. | false |
| Answer» A. true | |
| Explanation: metal forging is a forming operation that performs hammering to shape the metal component. in forging process, the metal component is heated sufficiently, and then it is hammered by using a hammer which can be performed manually or by automation, depending on the scale of production and properties required in the forged metal component. | |
| 144. |
During roll forming, a flat strip is passed number of times through the rollers. |
| A. | true |
| B. | false |
| Answer» A. true | |
| Explanation: in roll forming, a flat strip is gradually formed to the finished shape. the forming is almost exclusively accomplished by rotating contoured rolls while the material passes through the mill. | |
| 145. |
Which of following is necessary in order to have a good set of rolls? |
| A. | short horizontal distances |
| B. | small lead-in flanges |
| C. | a smooth flow of material |
| D. | less number of forming passes |
| Answer» C. a smooth flow of material | |
| Explanation: the probability of having a good set of rolls is to follow few rules: | |
| 146. |
Which of the following is true in case of “too quick” forming (too few passes)? |
| A. | it makes the tooling and the process uneconomical |
| B. | it makes process easier |
| C. | it distorts the product |
| D. | eliminate the need of a skilled operator |
| Answer» C. it distorts the product | |
| Explanation: “too quick” forming (too few passes) will distort the product because of the unacceptable level of stresses generated in the metal. on the other hand, too many passes will make the tooling and the process uneconomical. | |
| 147. |
What is “leg length” or “leg height”? |
| A. | the maximum vertical dimension of the profile |
| B. | total length of the product |
| C. | excess length of the product |
| D. | maximum width of the section |
| Answer» A. the maximum vertical dimension of the profile | |
| Explanation: the depth of the section, also called as “leg length” or “leg height”, is the maximum vertical dimension of the profile as it exits from the last pass. sometimes it called as “depth of corrugation”. | |
| 148. |
What will be the elongation if a 1in high section is formed in four passes in a mill having a horizontal distance (between passes) of 14in? |
| A. | 0.04% |
| B. | 0.16% |
| C. | 0.63% |
| D. | 0.50% |
| Answer» A. 0.04% | |
| Explanation: here, h = 1in; number of passes | |
| 149. |
During roll forming, the strain (elongation) of the outside edge fiber of the strip must remain below the uniform engineering strain (elastic limit). |
| A. | true |
| B. | false |
| Answer» A. true | |
| Explanation: if the strain (elongation) exceeds the elastic limit, then the edge of the finished product will become permanently strained. due to which the finished product will be wavy or the product will have a bow, camber or twist. | |
| 150. |
What is camber in roll forming? |
| A. | deviation of the strip edge from a straight line in horizontal plane |
| B. | deviation of the strip edge from a straight line in vertical plane |
| C. | difference in theoretical and actual elongation of the strip |
| D. | waviness of the strip |
| Answer» A. deviation of the strip edge from a straight line in horizontal plane | |
| Explanation: camber is the deviation of the strip edge from a straight line in the | |
| 151. |
When forming “Z” sections, the product is twisted in the opposite direction to compensate the machine generated twist. |
| A. | true |
| B. | false |
| Answer» A. true | |
| Explanation: a common method used to compensate for the anticipated twist is to twist the product in the opposite direction in the mill, from pass to pass. this principle is used when forming “z” sections. in other cases, the counter-twisting is accomplished just in the last one or two passes. | |
| 152. |
Which of the following is a type of extrusion process? |
| A. | direct |
| B. | indirect |
| C. | impact |
| D. | all of the mentioned |
| Answer» D. all of the mentioned | |
| Explanation: classification of extrusion processes are shown below. | |
| 153. |
In direct extrusion process at higher temperature which of the following is used to avoid friction? |
| A. | oil |
| B. | lubricants |
| C. | molten glasses |
| D. | wax |
| Answer» C. molten glasses | |
| Explanation: for steels, stainless steel, and high temperature materials, glass is a good excellent lubrication. the reasons for this are as follows. i. glass contains its viscosity at elevated temperatures, ii. has good wetting characteristics, and 3. glass acts as a thermal barrier between the billet, the container and the die, thus minimizing cooling. | |
| 154. |
In which of the following process frictional loss is eliminated at the billet container interface? |
| A. | direct |
| B. | indirect |
| C. | impact |
| D. | hydrostatic |
| Answer» D. hydrostatic | |
| Explanation: in hydrostatic extrusion process frictional loss is eliminated at the billet container interface. this elimination increases the quality of the product. | |
| 155. |
In which of the following process fluid medium is used to apply the load on the billet? |
| A. | direct |
| B. | indirect |
| C. | impact |
| D. | hydrostatic |
| Answer» D. hydrostatic | |
| Explanation: in hydrostatic extrusion process fluid medium is used to apply the load on the billet. as hydro stands for fluid and static for rest. | |
| 156. |
Extrusion is similar to? |
| A. | rolling |
| B. | forming |
| C. | welding |
| D. | casting |
| Answer» A. rolling | |
| Explanation: extrusion is similar rolling in producing constant cross-sectional shape. | |
| 157. |
Which defect arises due to high friction or high speed? |
| A. | tearing |
| B. | surface cracking |
| C. | tearing & surface cracking |
| D. | flaking |
| Answer» C. tearing & surface cracking | |
| Explanation: the defects such as, surface cracking and tearing, occurs with high friction or speed. these can also occur with stickling of billet material on die land. | |
| 158. |
Which of the following defect is also known as bamboo defect? |
| A. | blow hole |
| B. | cold shut |
| C. | surface cracking |
| D. | pipe defect |
| Answer» C. surface cracking | |
| Explanation: bamboo defects are periodic surface cracks that develop due to the extruded product sticking to the die land. | |
| 159. |
Which of the following defect tends to draw surface oxides and impurities towards the centre of billet? |
| A. | blow hole |
| B. | cold shut |
| C. | surface cracking |
| D. | pipe defect |
| Answer» D. pipe defect | |
| Explanation: pipe defect is the formation of sin hole at the end of the billet. it is associated with direct extrusion. the use of | |
| 160. |
Which of the following defect is also known as fish tailing? |
| A. | surface cracking |
| B. | pipe defect |
| C. | tearing |
| D. | internal cracking |
| Answer» B. pipe defect | |
| Explanation: in extrusion, the pipe defect is also termed as “tail pipe”, and “fish tailing”. it occurs during hot extrusion due to the presence of impurities and oxides. | |
| 161. |
For proper stretching operation, the metal sheet should be stressed above its yield strength. |
| A. | true |
| B. | false |
| Answer» A. true | |
| Explanation: in stretch forming, a metal sheet is stretched by the help of stretcher machines. for proper and complete stretching of sheet, the material is deformed plastically which is also called as permanent deformation. the metal sheet is stressed above its yield strength for successfully achieving the plastic deformation of the metal sheet. | |
| 162. |
In stretch forming, forming limit curve (FLC) is defined as a locus of all the limit strains in different strain paths of the sheet metal. |
| A. | true |
| B. | false |
| Answer» A. true | |
| Explanation: in stretch metal forming process, the forming limit curve (flc) provides quantification about the formability of sheet metal, which basically gives the details about the quality of material. the forming limit curve (flc) is generally defined as a locus of all the limit strains in different strain paths like deep drawing and biaxial stretching, of the sheet metal. | |
| 163. |
The stretch forming process is generally performed by using a hydraulic operated ram. |
| A. | true |
| B. | false |
| Answer» A. true | |
| Explanation: the stretch forming process is generally performed by using a hydraulic operated ram. in this process, first a single form block is used along with the gripping jaws, and then the metal is gripped and stretched by applying high tensile forces until it deforms plastically. and then the sheet metal is bent and rolled around a form block. | |
| 164. |
Rubber forming is a type of forming process in which polyurethane is used as a die material. |
| A. | true |
| B. | false |
| Answer» A. true | |
| Explanation: rubber forming is a type of forming process in which a polyurethane or rubber pad is commonly used as the die material instead of a rigid material. these materials are highly resistance to the abrasion and have a better fatigue life. and pressures of the order of 100 bar are typical of this process. this process is also called as guerin process. | |
| 165. |
The metal forging operation can only be performed by manual means. |
| A. | true |
| B. | false |
| Answer» B. false | |
| Explanation: metal forging is a forming operation which usually performs hammering process to shape the metal part. in the forging process, the metal part is heated sufficiently, and then it is hammered by using a hammer which can be performed by manual means or by automation, depending on the scale of production. | |
| 166. |
Which of the following metal forming processes performs squeezing out of material through a hole? |
| A. | forging |
| B. | rolling |
| C. | drawing |
| D. | extrusion |
| Answer» D. extrusion | |
| Explanation: extrusion process is a type of metal forming process, in which the material is forced or squeezed out through a hole called die. this process is very similar to squeezing out the toothpaste from the tube. this process is mainly used for metals that are ductile in nature like copper, steel, | |
| 167. |
Metal forming is a process in which the metal is deformed plastically to get into the desired shape. |
| A. | true |
| B. | false |
| Answer» A. true | |
| Explanation: in general, the metal forming is a large set of manufacturing processes in which the metal is deformed plastically to get into the shape of the die geometry. the tools like dies and punches are mostly used in the processes for the deformation of the material. for the plastic deformation, stresses beyond the yield strength of the material is required. | |
| 168. |
Which of the following processes is not the type of bulk forming process in the metal forming? |
| A. | bending |
| B. | rolling |
| C. | forging |
| D. | extrusion |
| Answer» A. bending | |
| Explanation: bulk forming is a deformation process which results in a massive shape change of the material. the ratio of surface area to volume of the material is relatively small. it includes processes like forging, extrusion and rolling. but the bending process is a part of sheet metal forming which has surface area to volume ratio relatively high. | |
| 169. |
Which of the following manufacturing processes is mainly considered for producing the components of very high strength? |
| A. | casting |
| B. | forging |
| C. | extrusion |
| D. | rolling |
| Answer» B. forging | |
| Explanation: forging is a deformation process in which the material is compressed | |
| 170. |
In metal forging process, the gravity drop hammers are operated by a ram using steam or pressurized air. |
| A. | true |
| B. | false |
| Answer» B. false | |
| Explanation: in the metal forming process, drop hammers are mainly of two types which are gravity drop hammer and power drop hammer. gravity drop hammers are the tools which achieve their energy by the falling weight of a heavy ram. the force mainly depends on the height of the drop and the weight of the ram. and power drop hammers are in which a ram is accelerated by the steam or pressurized air. | |
| 171. |
Which of the following metal forming processes is best suitable for making the wires? |
| A. | forging |
| B. | extrusion |
| C. | drawing |
| D. | rolling |
| Answer» C. drawing | |
| Explanation: drawing is a metal forming process which is widely used for making the wires from round bars of metal. this process is similar to extrusion process, except that instead of pressure on the metal mass, in drawing, the wire is pulled from one side of the metallic round bar which results into the formation of thin wires. this process is only suitable for ductile materials. | |
| 172. |
Stretch forming is a sheet metal forming operation in which shearing is taking place to deform the material. |
| A. | true |
| B. | false |
| Answer» B. false | |
| Explanation: stretch forming is a type of sheet metal forming process in which the metallic sheet is intentionally stretched and bent simultaneously to produce different shapes of the stretched sheet metal. the metal sheet is generally held by jaws at the ends. | |
| 173. |
Metal used for electroforming process absorbs energy from the magnetic field to get deform. |
| A. | true |
| B. | false |
| Answer» A. true | |
| Explanation: in the electromagnetic forming process, the conductivity of the metal and the eddy currents which makes contact with magnetic field creates a net pressure on the surface of the metal. then the metal surface moves inward due to the effect of this pressure, this mainly occurs due to the transfer of energy from the magnetic field to the metal. | |
| 174. |
In the electromagnetic forming process, the forming pulse is kept longer to optimize the use of energy. |
| A. | true |
| B. | false |
| Answer» B. false | |
| Explanation: in the electromagnetic forming process, the metal absorbs energy from the magnetic field to get deformed. to utilize most of this energy to forming operation, and to reduce the energy loss due to resistance heating, the forming pulse is kept short for better optimization of energy produced by the magnetic field. in general, pulse has duration of between 10 and 100 second. | |
| 175. |
Which of the following methods of forming is not the part of electromagnetic forming? |
| A. | compression |
| B. | expansion |
| C. | shearing |
| D. | counter forming |
| Answer» C. shearing | |
| Explanation: in the electromagnetic forming process, electromagnetic formation mainly used for three forming methods which can be compression, expansion, and counter forming. for compression, a tubular metal is compressed by a coil, usually against a grooved tube. and shearing is a different | |
| 176. |
The process of electromagnetic forming does not require any kind of lubrication. |
| A. | true |
| B. | false |
| Answer» A. true | |
| Explanation: in most of the forming processes, tool contacts with the specimen to get the desired output. but in the case of electromagnetic forming, the magnetic field is used to apply the pressure on the surface of a metal, which normally does not require any kind of lubrication. and it leaves no any tool marks on the metal surface. | |
| 177. |
Which of the following is the main advantage of using the electromagnetic forming process? |
| A. | high speed |
| B. | low maintenance |
| C. | applicable to all materials |
| D. | no spring-back |
| Answer» D. no spring-back | |
| Explanation: in the electromagnetic forming process, the metal is loaded and achieve plastic region, which results in plastic or permanent deformation, so that the spring- back associated with the mechanical forming process is completely eliminated because no any mechanical contact is present during the process of metal forming. | |
| 178. |
What is the maximum pressure required in a compression molding process? |
| A. | 35 mpa |
| B. | 40 mpa |
| C. | 45 mpa |
| D. | 50 mpa |
| Answer» D. 50 mpa | |
| Explanation: the maximum pressure that is required for the complete operation of compression molding is 50 mpa. | |
| 179. |
In compression molding, the curing time does not depend on which of the following factors? |
| A. | material |
| B. | curing temperature |
| C. | geometry |
| D. | thickness |
| Answer» B. curing temperature | |
| Explanation: when there has to be molding done for thermosetting materials, mainly compression molding is preferred. while doing this, curing has to be done. the time needed for curing depends on the material used, geometry and thickness of the material. | |
| 180. |
What is the maximum curing time required in a compression molding process? |
| A. | 2 minutes |
| B. | 3 minutes |
| C. | 4 minutes |
| D. | 5 minutes |
| Answer» D. 5 minutes | |
| Explanation: the maximum curing time that is required for the complete operation of compression molding is 5 minutes. | |
| 181. |
What is the minimum pressure required in a transfer molding process? |
| A. | 20 mpa |
| B. | 40 mpa |
| C. | 50 mpa |
| D. | 70 mpa |
| Answer» A. 20 mpa | |
| Explanation: the maximum pressure that is required for the complete operation of transfer molding is 20 mpa. | |
| 182. |
Speed of production in transfer molding is higher than that of compression molding? |
| A. | true |
| B. | false |
| Answer» A. true | |
| Explanation: it is counted among one of the advantages of transfer molding over compression molding that the speed of production is quite higher. not just that, but the maintenance in transfer molding too is lower than compression molding. | |
| 183. |
Thermosetting plastics are generally used for making products of high strength and rigidness. |
| A. | true |
| B. | false |
| Answer» A. true | |
| Explanation: thermosetting polymers basically involve cross-linked molecular structure and thus it is ideal for making products which demand rigidity and strength. due to cross linking in thermosetting polymers, these are made hard, tough, and cannot be re-moulded as thermoplastic polymers. | |
| 184. |
Which of the following types of molecular structure present in thermosetting polymers? |
| A. | linear polymers |
| B. | branched polymers |
| C. | cross-linked polymers |
| D. | network polymers |
| Answer» C. cross-linked polymers | |
| Explanation: cross-linked polymers are described by adjacent linear chains that are brought one to another at several locations by covalent bonds. cross linking is completed by a non-reversible chemical reaction. often, cross-linking is finished by additive atoms which are covalently bonded to the chains in the thermosetting polymers. | |
| 185. |
Polyethylene, polypropylene and polyvinyl chloride (PVC) are the main example of thermosetting polymers. |
| A. | true |
| B. | false |
| Answer» B. false | |
| Explanation: polyethylene, polypropylene and polyvinyl chloride (pvc) are basically examples of thermoplastics material. and thermosetting material’s example includes polyurethanes, polyesters, epoxy resins and phenol resins which are used for manufacturing of aircraft parts, tires and auto parts. | |
| 186. |
Polyurethane plastics are highly reactive to chemical compounds due to lack of elasticity in these plastics. |
| A. | true |
| B. | false |
| Answer» B. false | |
| Explanation: polyurethane plastics come in the category of thermosetting plastics. in this type of plastics, elasticity is generally very high. due to this property of high elasticity, it can be used in decorative and protective coatings. the high elasticity also makes these polyurethane polymers highly resistant to any chemical attack. | |
| 187. |
Phenolic plastics can also be used as binder for holding plies of wood in making of plywood. |
| A. | true |
| B. | false |
| Answer» A. true | |
| Explanation: phenolic plastics or polymers are belongs to thermosetting plastics. these are the special type of resins which can be used in potting compounds, casting resins, and laminating resins. they can also be used in making of electrical equipment. phenolic plastics are very popular binders for holding plies of wood in manufacturing of plywood. | |
| 188. |
Thermosetting plastics can be used for manufacturing of windshield for airplane. |
| A. | true |
| B. | false |
| Answer» B. false | |
| Explanation: for the manufacturing of windshield for airplane, poly-acrylics plastics are used which basically belongs to the group of thermoplastics. poly-acrylics are transparent, high tough in nature and can be easily shaped in any form. due to such properties of this material, it is widely used for making of windshields for airplane. | |
| 189. |
How is the die used in injection molding cooled? |
| A. | oil |
| B. | air |
| C. | water |
| D. | contact with cold surface |
| Answer» C. water | |
| Explanation: when it comes to molding of polymers in thermoplastics, injection molding process is the most common of the methods. in this method, whenever the die has to be cooled, there is water used to cool it. | |
| 190. |
How does the piston in the clamping unit move? |
| A. | hydraulic energy |
| B. | pneumatic energy |
| C. | heat energy |
| D. | suction |
| Answer» A. hydraulic energy | |
| Explanation: there is a clamping unit employed for holding the two halves together and for the opening and closing of the mold. a moving piston is provided which operates the power press. this piston works on hydraulic energy. | |
| 191. |
Which of the following material is not made by injection molding? |
| A. | nuts |
| B. | tubes |
| C. | car handles |
| D. | electrical fittings |
| Answer» B. tubes | |
| Explanation: injection molding is one of the most widely used method of molding among molding with polymers. there are various applications of this method such as nuts, bolts, cups, car handles, electrical fitting parts, but not tubes and rods. | |
| 192. |
What is the minimum pressure allowed to be given to the injection molding process? |
| A. | 90 mpa |
| B. | 100 mpa |
| C. | 140 mpa |
| D. | 170 mpa |
| Answer» B. 100 mpa | |
| Explanation: none. | |
| 193. |
The barrel is used for the opening and closing of the mold. |
| A. | true |
| B. | false |
| Answer» B. false | |
| Explanation: a barrel is an instrument that is placed near the nozzle, and it plays no role in the opening and closing of the mold. there is a clamping unit employed for holding the two halves together and for the opening and closing of the mold. | |
| 194. |
In blow molding, to inflate soft plastic, which medium is used? |
| A. | air |
| B. | water |
| C. | oil |
| D. | alcohol |
| Answer» A. air | |
| Explanation: blow molding process is typically used for the blowing process of hollow plastics. while blow molding, the plastic has to be inflated, in order to do so, air has to be blown inside with a high amount of pressure. | |
| 195. |
Which of the following plastics is not used in blow molding? |
| A. | terephthalate |
| B. | polypropylene |
| C. | polythene |
| D. | pvc |
| Answer» A. terephthalate | |
| Explanation: for blowing processes, there are certain plastics only which are properly suited for the operation, while any other | |
| 196. |
What is the minimum air pressure required in the blow molding process? |
| A. | 350 kpa |
| B. | 400 kpa |
| C. | 450 kpa |
| D. | 500 kpa |
| Answer» B. 400 kpa | |
| Explanation: in the blow molding process, there is some amount of pressure that has to be given to the air for blowing the bottles. the amount of pressure to be given depends on the material. the minimum pressure that can be given in this process is 400 kpa. | |
| 197. |
What can be the maximum pressure to be given to plastic for blow molding process? |
| A. | 700 kpa |
| B. | 750 kpa |
| C. | 800 kpa |
| D. | 850 kpa |
| Answer» C. 800 kpa | |
| Explanation: air with an extreme amount of pressure, when is needed, it might mean the material is thicker and denser. the amount of pressure that can be provided depends totally on the material. the maximum pressure that can be provided in blow molding process is 800 kpa. | |
| 198. |
Which of the following is not a type of blow molding process? |
| A. | injection blow molding |
| B. | extrusion blow molding |
| C. | multi-smaller blow molding |
| D. | multi-larger blow molding |
| Answer» C. multi-smaller blow molding | |
| Explanation: blow molding basically is a process of inflation of air under pressure into the plastics inside the mold cavity. there are only three known types of blow molding, | |
| 199. |
What is the minimum thickness required by the plastic for vacuum forming? |
| A. | 0.125 mm |
| B. | 0.25 mm |
| C. | 0.375 mm |
| D. | 0.5 mm |
| Answer» A. 0.125 mm | |
| Explanation: vacuum forming is one of the classifications of thermoforming processes. around its circumference, a clamp is attached or we need to know the minimum thickness. the minimum thickness that can be allowed for this operation is 0.125 mm. | |
| 200. |
What is the maximum thickness that can be allowed for a plastics sheet in a vacuum forming process? |
| A. | 3 mm |
| B. | 3.1 mm |
| C. | 3.2 mm |
| D. | 3.3 mm |
| Answer» C. 3.2 mm | |
| Explanation: vacuum forming process is one of the important processes that are employed in thermoforming processes. the maximum thickness of the plastic sheet has to be noted, as a clamp is to be fitted around the plastic | |
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