McqMate
These multiple-choice questions (MCQs) are designed to enhance your knowledge and understanding in the following areas: Mechanical Engineering .
| 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 | |
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