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20 Mechanical Engineering Questions And Answers For Interview Pdf – 2021


Mechanical engineering questions and answers for interview pdf has been written for the candidates preparing for the interview for getting placement in the companies. These interview mechanical engineering questions and answers will help you in your job interview selection as a Mechanical engineer.

Mechanical Engineering Questions And Answers For Interview Pdf

The mechanical engineering is one of the oldest engineering branches that are being pursued by many students on a global scale. A mechanical engineering interview can be intimidating. A good idea is to practice answering questions that you may be asked. You will need to study hard for this test, as it will cover all of the basics of mechanical engineering. If you are not prepared, you run the risk of losing valuable time on the job training process.


This page gives you interview mechanical engineering questions and answers for students, frequently asked mechanical engineering questions for interviews. These questions are not arranged in any order of difficulty. Engineers mostly ask these questions to find out the level of your knowledge and whether you can reason logically.

1. Which is false statement about case hardening? Case hardening is done by | Mechanical Engineering Questions and Answers For Interview Pdf

a. Electroplating

b. Cyaniding

c. Induction hardening

d. Nitriding

e. Flame hardening

case hardening process of gears - Heat treatment of gears - strengthening gears - interview mechanical engineering questions
Case Hardening of Gears




In the case hardening process, it adds a thin layer of metal alloy to the outer surface of the metal. Thus, this process can minimize wear and tear of metals and also, it increases the strength of steels parts surface.

Some of the case hardening process are:

Flame or Induction hardening; Carburizing; Nitriding; Cyaniding; Carbonitriding; Ferritic Nitrocarburizing.

2. Gun metal contains | Interview Mechanical Engineering Questions

a. 70% copper and 30% zinc

b. 90% copper and 10% tin

c. 85-92% copper and rest tin with little lead and nickel

d. 70-78% copper and rest tin

e. 85-92% copper and rest zinc


85-92% copper and rest tin with little lead and nickel

3. Which of the following is not a casting defect | Mechanical Engineering Questions for Interview

a. Hot tear

b. Blow hole

c. Scab

d. Decarburization

e. Shift

casting defects in manufacturing - mechanical engineering questions for interviews
Casting Defects



4. Draft on pattern for casting is | Interview Mechanical Engineering Questions

a. Shrinkage allowance

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b. Identification number marked on it

c. Taper to facilitate its removal from mould

d. Increase in size of cavity due to shaking of pattern

e. For machining allowance


Taper to facilitate its removal from mould


Pattern draft is the taper placed on the pattern surfaces that are parallel to the direction in which the pattern is withdrawn from the mould (i.e perpendicular to the parting plane), to allow removal of the pattern without damaging the mould activity.

5. The increase in hardness due to cold working is called | Mechanical Engineering Questions for Interview

a. Cold hardening

b. Hot hardening

c. Work hardening

d. Age hardening

e. Induction hardening

work hardening process - material strengthening-Mechanical Engineering Questions And Answers For Interview Pdf
Work Hardening Treatment By LASER


Work hardening

6. Which one of the following types of impellers is used to handle highly solid laden liquids like concrete and slurry | Mechanical Engineering Questions and Answers For Interview PDF

a. Fully Open Impeller

b. Semi-Enclosed Impeller

c. Fully Enclosed Impeller

d. Quarter Open Impeller


a. Fully Open Impeller


Impeller types

Fully Enclosed Impeller:

In this enclosed / closed / shrouded impellers, the vanes are covered with side plates on both sides. The back plate is mounted into the shaft and the front plate is coupled by the vanes. This type of setup achieves higher efficiency and run for a prolonged period, and it’s mainly used for the supply of cold water, hot water and acids.

Semi Enclosed Impeller:

This type of vanes has only backside plate. This rugged pump will handle liquids containing fibrous material such as paper pulp, sugar molasses and sewage water etc.

Open Impeller:

This type of impellers had no plate on either side i.e. vanes are open. This type of rough duty pumps which handles abrasive liquids such as concrete (the mixture of water, sand, pebbles and clay) and slurry.

7. For the operating point of the pump, a system characteristic between the head required ‘H’ and the discharge to be maintained ‘Q’ is generally expressed as | Interview Mechanical Engineering Questions

a. Linear equation

b. Parabolic equation

c. Exponential equation

d. Cubic equation


b. Parabolic equation


Centrifugal pump performance curve, H v Q curve
Centrifugal pump characteristics curve

When selecting a pump for any industrial or personal use, it is critical to first establish the total head needed for the operation as well as the required flow rate for the application. All of this information is essential because each pump that is produced by a manufacturer has a characteristic value of head and flow at which it operates at peak efficiency.

In a pump performance curve, the relationship between differential head and operating flow rate is graphed. Pump curves are used to determine whether or not the pumps would still be the best match for the changed needs that have been identified.

8. A Centrifugal pump acts as a reverse of | Mechanical Engineering Questions for Interview

a. Outward radial flow reaction turbine

b. Pelton turbine

c. Inward radial flow reaction turbine

d. Reciprocating pump


c. Inward radial flow reaction turbine


Centrifugal pump vs Reaction Turbine
Centrifugal pump vs Reaction Turbine

When water flows from outward to inward then it is known as ‘Inward Radial Flow reaction Turbine‘ as shown in figure. The water enters from the penstock enters the casing and from their it enters into stationary guide wheels. The guide vanes on guide wheel direct the water to the runner (also known as ‘forced vortex‘). The water enters at outer diameter of runner and discharge at inner diameter of the runner.

9. What is the major problem in hot extrusion? | Interview Mechanical Engineering Questions

a. Design of punch

b. Design of die

c. Wear and tear of die

d. Wear of punch


b. Design of die


Hot extrusion is the process of heating appropriate metals and alloys to the right temperature and then inserting the heated stock into the cylinder of an extrusion press to produce a finished product. Using the pressure created by a moving ram or piston, plastic metal is forced through a die that has been designed specifically for it.

In hot extrusion, one of the most difficult issues to deal with is the impact of hot metal on the equipment. To keep the dies safe, a variety of techniques are used. For each component, the die may be replaced and let to cool completely.

10. Which bond is used in grinding wheels for the very high class surface finish with close dimensional accuracy? | Mechanical Engineering Questions for Interview

a. Rubber bond

b. Vitrified bond

c. Silicate bond

d. Oxychloride bond


a. Rubber bond


Grinding Wheel Bond Types - Grinding Wheel Bonding Material - Bond Grade
Grinding Wheel Bond Types

A bonding substance holds the abrasive grains together in a grinding wheel. During the grinding process, the bonding substance does not cut. Its primary purpose is to secure the grains in different degrees of strength. Silicate, vitrified, resinoid, shellac, rubber, and metal are all common grinding wheel bonds.

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Rubber bond:

Rubber bond wheels are very robust and durable. Their primary applications are narrow cut-off wheels and drive wheels for centerless grinding machines. Additionally, they are utilized when very fine finishes on bearing surfaces are needed.

Vitrified bond:

More than 75% of all grinding wheels are made of vitrified bonds. These bonds are composed of finely powdered clay and fluxes that are completely combined with the abrasive.

Silicate bond:

When the heat produced by grinding must be kept to a minimum, silicate bonding materials are utilized. This substance easily dislodges the abrasive grains in comparison to other bonding agents. This is the most flexible bond available in a grinding wheel.

The oxychloride bond:

This is an organic bond that is utilized in grinding wheels to create very smooth finishes on components such as rolls, silverware, camshafts, and crank pins. They are generally not utilized in heavy-duty grinding activities.

11. In Die cutting operation, punching a number of holes in a sheet is called | Interview Mechanical Engineering Questions

a. Perforating

b. Parting

c. Notching

d. Lancing


a. Perforating


Sheet Metal Press Working Operations
Sheet Metal Working Operations

Shearing is a cutting process that is used to extract a blank with the desired dimensions from a big sheet of material. Punching, blanking, piercing, notching, trimming, and nibbling are all shearing processes that use a die.

Punching / Blanking:

Punching is a method of removing material from a bigger item or a sheet of sheet metal. If the tiny removed piece is discarded, the process is referred to as punching; if the small removed piece contains the usable portion and the remainder is junk, the technique is referred to as blanking.


It is a method of cutting a hole in metal. Unlike punching, piercing does not result in a slug.


It is a process that involves punching a series of evenly spaced holes in a sheet of metal. Holes of any size or form are acceptable. Typically, they encircle the whole sheet of metal.


It is a process that removes a predetermined quantity of metal from the edges.


It is the process of cutting a sheet metal lengthwise and then bending the cut part.

12. If there is no melting of the edges of the base metal a the root face or on the side face or between the weld runs, then it is | Mechanical Engineering Questions for Interview

a. Lack of penetration

b. lack of fusion

c. Burn through

d. Excessive penetration


b. Lack of fusion


Gas Welding Defects

A flaw is a defect in the weld that may cause the welded junction to fail in service. The following defects are often encountered in gas welding.

Incomplete Penetration:

Incomplete penetration occurs when the weld metal does not reach the root of the joint. The following factors contribute to this defect: insufficient penetration; excessive welding speed; low current setting; usage of a bigger diameter electrode. As a result of insufficient cleaning or gouging prior to depositing sealing run.

Lack of fusion:

Lack of fusion occurs when the edges of the base metal do not melt at the root face, side face, or between the weld runs. The following are common causes of defects: insufficient heat input; incorrect electrode and torch angle; insufficient welding current; excessive welding speed.

Burn through:

The main cause of burn through is excessive heat. Additionally, having an excessively wide root hole at the weld joint may result in burn through. If burn through occurs, reducing the voltage or wire feed speed may assist in resolving the issue.

Excessive penetration:

Metal flows onto the base metal’s surface without fusing it. The following are common causes of defects: improper welding technique; excessive welding current; and the use of big electrodes.

13. Internal gears are manufactured by | Interview Mechanical Engineering Questions

a. Hobbing

b. Shaping with pinion cutter

c. Shaping with rack cutter

d. Milling


b. Shaping with pinion cutter


Gear shaping:

It is a process of internal gear generation. The cutter is just a gear with cutting edges attached. The tool is rotated at the necessary feed rate in relation to the gear being produced, and each tooth gap in the manufactured gear is formed by a single full cutter tooth. This technique enables the production of cluster gears, internal gears, racks, and other components that are not possible to make via gear hobbing.

Gear hobbing:

It is a continuous generating process in which the evenly spaced cutting edges of the hob create the teeth sides of the continuously moving workpiece. The primary benefit of this technique is its flexibility in producing a number of gear types, such as spur, helical, worm wheel, and spline. The primary benefit of this technique is the increased gear manufacturing rate achieved via continuous indexing.

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Gear milling:

It is one of the earliest and most well-known metal removal processes used in the manufacture of gears. This procedure necessitates the use of a milling machine. Currently, this technique is only utilized to produce gears with a very low need for dimensional precision.

Gear forming:

When cutting gear shapes, the cutting tool’s cutting edge has the same shape as the gap between the gear teeth. Milling and broaching are two machining processes that may be used to create cut gear teeth.

Thus, internal gears are formed using a pinion cutter. External gears are often formed by honing, milling, and shaping using a rack cutter.

Hobbing, milling and a rack cutter shaping machine do not have enough space to move on internal surfaces for cutting.

14. In submerged arc welding, the arc is struck between | Mechanical Engineering Questions for Interview

a. Consumable coated electrode and work piece

b. Non-consumable electrode and workpiece

c. Consumable bare electrode and work piece

d. Tungsten electrodes and work piece


c. Consumable bare electrodes and work piece


Submerged arc welding is a type of arc welding process in which heat is created between bare consumable electrode wire and the work item through an arc. The arc and weld zone are fully encased in a covering of granular, fusible flux that melts and seals the weld pool against ambient air. The molten flux interacts with the molten metal, producing slag that enhances its characteristics and subsequently floats on top of the molten metal, shielding it from ambient gas contamination and slowing the cooling rate.

15. When setting up a mechanical drawing in AutoCAD the drafter should set the units to | Interview Mechanical Engineering Questions

a. Metric

b. Decimal

c. Fractionjal

d. Architectural


b. Decimal

16. The property by virtue of which sand mould is capable of withstanding a high temperature of the molten metal without fusing is known as | Mechanical Engineering Questions for Interview

a. Porosity

b. Adhesiveness

c. Cohesiveness

d. Refractoriness


d. Refractoriness

17. In tool signature, nose radius is indicated | Interview Mechanical Engineering Questions

a. In the middle

b. In the beginning

c. Not indicated

d. At the end


d. At the end


18. Plastic can be welded by the following process | Mechanical Engineering Questions for Interview

a. TIG Welding

b. MIG Welding

c. Electron beam welding

d. Ultrasonic welding


d. Ultrasonic Welding


Ultrasonic welding is a technique suitable for joining both similar and dissimilar metal workpiece or welding a piece of metal to a metalized substrate such as ceramics or glass. The weld formation is caused by the application of external pressure and ultrasonic vibrations.

19. In a fusion welding process | Interview Mechanical Engineering Questions

a. only heat is used

b. only pressure is used

c. combination of heat and pressure is used

d. none of these


a. only heat is used


Fusion welding is defined as melting together and joining metals by means of heat. It uses heat to melt the base metals and may add a filler metal. The thermal energy required for these operations is usually supplied by chemical or electrical means. Filler may or may not be used.

20. For welding metals less than 5 mm thick, following method of gas welding would give best results | Mechanical Engineering Questions for Interview

a. Forehand

b. Backhand

c. Straight hand

d. Inclined hand


a. Forehand


For welding metals less than 5 mm thick, fore hand method of gas welding would give best results.

Conclusion of Mechanical Engineering Questions And Answers For Interview Pdf:

If you are looking for some good Mechanical Engineering questions for Interview PDF, then you have come to the right place. Here we have given the list of Mechanical Engineering Questions and Answers for interview PDF for freshers as well as experienced candidates. You can download it or just read this interview question pdf which will help you to crack your next interview easily.

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