McqMate
These multiple-choice questions (MCQs) are designed to enhance your knowledge and understanding in the following areas: Mechanical Engineering .
| 251. |
Forging is a metal forming operation in which the metal is stretched to form the desired shape of a metal part. |
| A. | true |
| B. | false |
| Answer» B. false | |
| Explanation: forging is a metal forming operation in which heated metal is beaten by a hammer to give it the desired shape. it is basically a deformation process in which the material is compressed between dies by using impact load to deform it. forging can also be used for making complex shapes of metal parts. | |
| 252. |
In general, the casted metal part is much stronger and tougher than that produced by the forging operation. |
| A. | true |
| B. | false |
| Answer» B. false | |
| Explanation: in general, forged parts are much stronger and tougher than the casted parts made from the same metal. the metal components have high strength because the hammering operation maintains its structure that makes proper alignment of grains along the profile of metal components, which leads to an increase in strength. | |
| 253. |
The open die forging process is also known as upsetting or upset forging process. |
| A. | true |
| B. | false |
| Answer» A. true | |
| Explanation: in an open die forging process, the metal billet is heated up to a very high temperature and then compressed between two flat die halves. this method is like a compression test, which is also known as upsetting or upset forging. in the process, billet is basically deformed by a decrease in its height and increase in its diameter. | |
| 254. |
Which of the following processes is mainly used for making the connecting rods? |
| A. | casting |
| B. | deep drawing |
| C. | rolling |
| D. | forging |
| Answer» D. forging | |
| Explanation: connecting rods are generally manufactured by the forging operation. in forging, a hammer is used which strikes on the heated metallic part to get into the desired shape. the properties like strength, toughness, etc are greatly enhanced by performing the forging operation. forging can be open die forging or closed die forging. | |
| 255. |
In impression die forging process, extra deformed material is produced which is called a flash. |
| A. | true |
| B. | false |
| Answer» A. true | |
| Explanation: in impression die forging process, flash can be produced which is considered as scrap material that is removed from the formed part during the finishing of a metal part. but in flash-less forging, the metal is fully prevented within the die, so no flash is produced during the process. | |
| 256. |
A cone shaped die is used in the orbital forging for the forging of metal parts. |
| A. | true |
| B. | false |
| Answer» A. true | |
| Explanation: in the orbital forging process, forming is done to the meat part by using a cone-shaped die that is simultaneously rolled and pressed into the material. the metal part is supported on a lower die, because of inclined axis of cone. in the process, only a small area of the metal surface is compressed at the stage of forming. | |
| 257. |
When an asymmetrical section is roll formed, the finished product will have |
| A. | camber |
| B. | cross-bow |
| C. | a twist |
| D. | waviness |
| Answer» C. a twist | |
| Explanation: when an asymmetrical section is a roll formed, the finished product will have a twist after leaving the last pass, even if the starting material is flat. | |
| 258. |
Which of the following is true about the extrusion process? |
| A. | structure is homogeneous |
| B. | no time is lost in changing the shape |
| C. | service life of extrusion tool is too high |
| D. | its leading end is in good shape as compared to rolling |
| Answer» B. no time is lost in changing the shape | |
| Explanation: no time is lost in changing the shape as the dies may be readily removed in the process of extrusion. | |
| 259. |
In which extrusion process the direction of flow of metal is in same direction as that of ram? |
| A. | direct |
| B. | indirect |
| C. | impact |
| D. | hydrostatic |
| Answer» A. direct | |
| Explanation: direction extrusion is a process in which the metal billet, placed in a container is forced by a ram to pass through a die. in this type, the direction of flow of metals is, in same as that of movement of ram. the punch closely fits the die cavity to prevent the backward flow of the material. | |
| 260. |
Which of the following is not used because of the problem of handling extruded metal coming out through moving ram? |
| A. | direct |
| B. | indirect |
| C. | impact |
| D. | hydrostatic |
| Answer» B. indirect | |
| Explanation: indirect extrusion method is not used because of the problem of handling extruded metal coming out through moving ram. | |
| 261. |
Which of the following is not a cold extrusion process? |
| A. | cold extrusion forging |
| B. | impact extrusion |
| C. | hydrostatic extrusion |
| D. | cold rolling |
| Answer» C. hydrostatic extrusion | |
| Explanation: cold extrusion is done at room temperature or near room temeprature. the processes, impact extrusion, hydrostatic extrusion and cold extrusion forging are the types of cold forging. the advantages of this over hot extrusion are the lack of oxidation, higher strength due to cold working, closer tolerances, and good surface finish. | |
| 262. |
The centre of the extruded product can develop cracks called as? |
| A. | centre cracking |
| B. | centre burst |
| C. | arrow headed fracture |
| D. | all of the mentioned |
| Answer» D. all of the mentioned | |
| Explanation: cracks that are developed in the centre of extruded material is known as internal cracking. these are termed as “centre cracking”, “centre burst”, “chevron cracking”, and as “arrow head cracking”. | |
| 263. |
Which of the following processes of metal forming is best suited for making products like aircraft wings and window frames? |
| A. | forging |
| B. | rolling |
| C. | drawing |
| D. | stretch forming |
| Answer» D. stretch forming | |
| Explanation: stretch forming is a sheet metal forming process in which the sheet metal is clamped at the edges and stretched by using the dies or form blocks. and no any lubrication is required significantly during the process. this method is best suited for making the products like aircraft wings, window frames, automobile door panels etc. | |
| 264. |
Stretch forming is a process which involves tensile and bending forces during the operation. |
| A. | true |
| B. | false |
| Answer» A. true | |
| Explanation: in stretch forming process, stretching of a metal sheet is basically done by holding its edges and bending it on a cylindrical block, simultaneously is known as stretch forming. this process basically involves tensile and bending forces during the operation. in this process, the materials with high ductility are mostly stretched by rigid dies. | |
| 265. |
Forming is a process that changes the shape of the metal by changing its phase. |
| A. | true |
| B. | false |
| Answer» B. false | |
| Explanation: forming is basically a term that covers many manufacturing processes. in the metal forming process, the shape of the material or metal is changed by performing an operation like hammering, squeezing, bending, pulling etc. without changing its phase. the raw materials used in the forming process remained in a single solid phase. | |
| 266. |
Rolling is a forming process in which thickness of the metal plate is decreased by increasing its length. |
| A. | true |
| B. | false |
| Answer» A. true | |
| Explanation: rolling is a metal forming process in which the metal plate is squeezed between the two hard rollers. in the operation, the thickness is decreased and the length is increased as the volume of the metal is conserved. this method is mainly used for the production of thin metal plates which can be done by performing hot rolling or cold rolling, depending on the required mechanical properties. | |
| 267. |
In stretch forming, spring-back is a very complicated problem which causes trouble in operating machines during the process. |
| A. | true |
| B. | false |
| Answer» B. false | |
| Explanation: spring-back is basically defined as a phenomenon in which the material tries to regain its original shape during elastic loading condition. but in stretch forming process, the stretching and bending operations take place simultaneously which causes permanent deformation of the sheet metal. so, this combined effect results in negligible spring-back in the metal part and hence causes no problem in the operating machines. | |
| 268. |
3 WORKING PRINCIPLE AND APPLICATIONS - HYDRO FORMING - RUBBER PAD FORMING - METAL SPINNING |
| A. | forging |
| B. | rolling |
| C. | drawing |
| D. | stretch forming |
| Answer» D. stretch forming | |
| Explanation: stretch forming is a sheet metal forming process in which the sheet metal is clamped at the edges and stretched by using the dies or form blocks. and no any lubrication is required significantly during the process. this method is best suited for making the products like aircraft wings, window frames, automobile door panels etc. | |
| 269. |
High volume rate of production can be possible by stretch sheet metal forming process. |
| A. | true |
| B. | false |
| Answer» B. false | |
| Explanation: in stretch forming, the sheet metal is fixed with stretch gripper with the support of a tool, and then operation takes place in a hydraulic stretching unit. the process consumes too much time as the stretching process takes time to strain hardens the material. so, this process includes low volume rate of production, but the process is very versatile and have economic production. | |
| 270. |
Tangential stretch forming and simple stretch forming are quite similar to each other. |
| A. | true |
| B. | false |
| Answer» B. false | |
| Explanation: tangential stretch forming is very different from simple stretch forming. however, the purpose is same. in tangential stretch forming, the metal sheet is gripped from two opposite ends. the main difference to the simple stretch forming is that the form block and gripping jaws both are movable in this process. | |
| 271. |
In electromagnetic forming, highly intense magnetic field is used for the forming process. |
| A. | true |
| B. | false |
| Answer» A. true | |
| Explanation: in electromagnetic forming, many components like capacitor bank, forming coil, field shaper, conductive material etc. are used to create intense magnetic fields. this magnetic is generally produced by the discharge of capacitors into a coil, which lasts only for a few microseconds. then further processing is done to perform the metal forming. | |
| 272. |
The magnetic field interacts with metal to generate heat in the metal which causes forming process. |
| A. | true |
| B. | false |
| Answer» B. false | |
| Explanation: in the electromagnetic forming process, eddy currents are induced in a conductive material that is placed near to the coil. then it interacts with a magnetic field to cause mutual repulsion between the metal and the forming coil. this force of repulsion is mainly responsible for inducing stresses in the metal beyond its yield strength which results in plastic deformation of metal. | |
| 273. |
Electromagnetic forming cannot be used for materials of poor electrical conductivity. |
| A. | true |
| B. | false |
| Answer» B. false | |
| Explanation: the electromagnetic forming method uses a high intense magnetic field to deform the material. this process is primarily used for the forming of good conducting materials like copper, aluminum, silver etc. | |
| 274. |
The efficiency of electromagnetic forming mainly depends on the resistivity of material being formed. |
| A. | true |
| B. | false |
| Answer» A. true | |
| Explanation: the electromagnetic forming method uses a capacitor and forming coil to create intense magnetic field. the efficiency of the magnetic pulse mainly depends on the resistivity of the material being formed. for better output, the resistivity of the material must be less than 15 micro-ohm-centimeters. | |
| 275. |
The joints made by an electromagnetic forming process are much stronger than the parent material. |
| A. | true |
| B. | false |
| Answer» A. true | |
| Explanation: in the electromagnetic forming process, the joints made are much stronger than the parent material. this process also allows increased ductility for several alloys because of the lack of stresses and friction which normally encountered with the process. this method is widely used for a high rate of production. | |
| 276. |
What is the minimum pressure required in a compression molding process? |
| A. | 0.5 mpa |
| B. | 1 mpa |
| C. | 1.5 mpa |
| D. | 2 mpa |
| Answer» A. 0.5 mpa | |
| Explanation: processing of thermosetting plastics is classified as, compression molding and transfer molding. the minimum pressure that is required for the complete operation of compression molding is 0.5 mpa. | |
| 277. |
What is the minimum curing time required in a compression molding process? |
| A. | 0.4 minutes |
| B. | 0.5 minutes |
| C. | 0.6 minutes |
| D. | 0.7 minutes |
| Answer» B. 0.5 minutes | |
| Explanation: the minimum curing time that is required for the complete operation of compression molding is 0.5 minutes. | |
| 278. |
What is the maximum pressure required in a transfer molding process? |
| A. | 80 mpa |
| B. | 90 mpa |
| C. | 100 mpa |
| D. | 120 mpa |
| Answer» C. 100 mpa | |
| Explanation: processing of thermosetting plastics is classified as, compression molding and transfer molding. the maximum pressure that is required for the complete operation of transfer molding is 100 mpa. | |
| 279. |
Thermosetting materials are the polymeric materials which get soften on heating with or without pressure. |
| A. | true |
| B. | false |
| Answer» B. false | |
| Explanation: thermosetting materials are the polymeric materials that get permanent hardness once the heat is given to the material. these are the polymers which require heat and pressure to mould them into shape. these polymers cannot be re-softened once they are set and hardened by heat. | |
| 280. |
Polyurethanes plastics can be made in flexible foams even after belonging to thermosetting polymers. |
| A. | true |
| B. | false |
| C. | topic 5.2 injection moulding - plunger and screw machines |
| Answer» A. true | |
| Explanation: polyurethane plastics are belonged to the thermosetting plastics or polymers. polyurethane is the only polymer that can be formed in both rigid and flexible foams. the flexible polyurethane foam is generally used in the manufacturing of mattresses, carpets and furniture. and the rigid polyurethane foam is used in making of chairs and mirror frames. | |
| 281. |
Thermosetting plastics like epoxies can be used for filament wound rocket motor casings in missiles by combining with glass fibers. |
| A. | true |
| B. | false |
| Answer» A. true | |
| Explanation: epoxies can be used in various ways. in adding with glass fibers, it is capable of making composites that are of high strength and heat resistant. these composites are basically used for making motor casings in missiles, aircraft parts, fixtures etc. | |
| 282. |
Mechanical properties of any plastics are mainly dependent on the temperature, force and time of load applied. |
| A. | true |
| B. | false |
| Answer» A. true | |
| Explanation: mechanical properties relate to movement or breakage of the polymer due to some mechanical variation such as application of load. mechanical properties are mainly dependent on the temperature, force or load applied, and the duration of time the force is applied. it can also be affected by ultra-violet radiation when used outside. | |
| 283. |
Where does the granular molding material get loaded into? |
| A. | barrel |
| B. | hopper |
| C. | pellets |
| D. | split |
| Answer» B. hopper | |
| Explanation: in a ram or plunger type injection molding system, the granular molding material has to be first loaded into a hopper, after which, with the help of a feeding device it gets metered out inside a cylinder. | |
| 284. |
There is a varied pressure provided in the solidification unit of injection molding process. |
| A. | true |
| B. | false |
| Answer» B. false | |
| Explanation: injection molding is considered to be one of the most widely used methods. in this method, there are dies that eject the solidified component, before which it is kept under constant pressure. | |
| 285. |
Which of the following is not an application of blow molding process? |
| A. | toy bodies |
| B. | door liners |
| C. | bottles |
| D. | pipes |
| Answer» B. door liners | |
| Explanation: among the following, only door liners is not an application of blow molding process. internal door liners are made using thermoforming process, while toy bodies, bottles and pipes are made using blow molding process. | |
| 286. |
The heater in the vacuum forming process is heated up to 90°C. |
| A. | true |
| B. | false |
| Answer» A. true | |
| Explanation: in vacuum forming process, there is a clamp that has to be used for holding the plastic sheets. there is a heater employed for heating the mold cavity. the | |
| 287. |
The initial cost in blow molding is low. |
| A. | true |
| B. | false |
| Answer» A. true | |
| Explanation: in blow molding, there is a mold cavity present inside the soft plastic, into which, the air with high amount of pressure has to be blown. the capital required for mold initially is quite less, making it a little inexpensive process. | |
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