Interview Questions with Answers

1. What happens to the diameter of a hole when a plate with a hole is heated uniformly?

- It increases.

2. Mention types of welding?

Arc welding, TIG welding, Gas metal arc welding, Flux-cored arc welding, Electro slag welding.

3. What is the difference between welding, soldering and brazing?

Welding is a fabrication or sculptural process that joins materials, usually metals or thermoplastics, by causing coalescence. This is often done by melting the workpieces and adding a filler material to form a pool of molten material (the weld pool) that cools to become a strong joint, with pressure sometimes used in conjunction with heat, or by itself, to produce the weld

Soldering is a process in which two or more metal items are joined together by melting and flowing a filler metal into the joint, the filler metal having a lower melting point than the workpiece

Brazing is a metal-joining process whereby a filler metal is heated above and distributed between two or more close-fitting parts by capillary action.

 

4. What is yield point?

The yield strength or yield point is the stress at which a material begins to deform plastically.

5. What is shear stress?

A shear stress is defined as the component of stress coplanar with a material cross section. Shear stress arises from a force vector perpendicular to the surface normal vector of the cross section.

6.  Why there are holes or slots in the disc brakes in automobiles?

- To dissipate the enormous amount of heat generated while braking

7. How does a plane take off?

- Airspeed creates lift across the wings. The wings have a curvature, or camber, that increases the distance the air has to travel over the top of wing. This creates the Bernoulli effect. The Bernoulli Principle states that pressure in air decreases as the speed of the air increases. Faster air over the top of the wing lowers the pressure, and the difference created between the top and the bottom of the wing creates lift.

8. What are the types of boiler?

- Fire tube and Water Tube

9. What is a cantilever?

- A cantilever is a beam supported on only one end. The beam carries the load to the support where it is resisted by moment and shear stress. Cantilever construction allows for overhanging structures without external bracing. Cantilevers can also be constructed with trusses or slabs.

10. How will you extinguish an electrical fire?

- CO2

11. What is overdrive?

 Overdrive is a condition where the output of the transmission is revolving faster than the engine. Gear ratio is less than one.

12. Can the gear ratio be infinity?

- Yes. Eg: Rack and pinion. 

13. What is rack and pinion arrangement? Mention its application in day to day life?

- A rack and pinion is a type of linear actuator that comprises a pair of gears which convert rotational motion into linear motion. Eg: CD drive, Steering Wheel 

14. What are left/right hand screws? Mention applications.

- Where the rotation of a shaft would cause a conventional right-handed nut to loosen rather than to tighten due to fretting induced precession. Examples include:

• The left hand pedal on a bicycle.
• The left-hand grinding wheel on a bench grinder.
• The lug nuts on the left side of some automobiles.