700+ Mechanical Engineer Interview Questions and Answers

If pressure valve fails in boiler, shut down the boiler immediately and isolate it from the system.

• Shut down the boiler immediately to prevent any further damage.

• Isolate the boiler from the system to prevent any pressure build-up.

• Inspect the pressure valve to determine the cause of failure.

• Replace the pressure valve with a new one.

• Test the new pressure valve to ensure it is functioning properly before restarting the boiler.

An aeroplane consists of several basic parts that work together to enable flight.

• The wings generate lift and provide stability

• The fuselage houses the cockpit, passengers, and cargo

• The engines provide thrust to move the plane forward

• The tail section includes the horizontal stabilizer and vertical fin for directional control

• The landing gear allows the plane to take off and land

• The avionics system includes instruments and electronics for navigation and communication

The percentage of carbon presence in cast iron varies from 2.1% to 6.67% depending on the type of cast iron.

• Cast iron is classified into four types based on its carbon content: white, gray, ductile, and malleable.

• White cast iron has the highest carbon content, ranging from 2.1% to 6.67%.

• Gray cast iron has a lower carbon content, ranging from 2.5% to 4%.

• Ductile cast iron has a carbon content of 3.2% to 4.1%.

• Malleable cast iron has the lowest carbon content, ranging from 2.2% t...read more

Cooling a pipe in a chamber without coolant

• Use natural convection by placing the pipe vertically and allowing air to circulate around it

• Use a heat sink to absorb the heat from the pipe

• Use a thermoelectric cooler to create a temperature gradient and cool the pipe

• Use a phase change material to absorb the heat from the pipe

• Use a heat exchanger to transfer the heat from the pipe to a cooler fluid or gas

• Use a radiation shield to reflect the heat away from the pipe

I know software's like AutoCAD, SolidWorks, ANSYS, MATLAB, and their working algorithms.

• AutoCAD - used for 2D and 3D design and drafting

• SolidWorks - used for 3D modeling and simulation

• ANSYS - used for finite element analysis and computational fluid dynamics

• MATLAB - used for numerical computing and data analysis

Shutdown maintenance is planned maintenance while breakdown maintenance is unplanned.

• Shutdown maintenance is scheduled and planned in advance to minimize downtime.

• Breakdown maintenance is reactive and performed after a failure has occurred.

• Shutdown maintenance involves inspecting, repairing, and replacing equipment before it fails.

• Breakdown maintenance involves repairing or replacing equipment after it has failed.

• Shutdown maintenance is usually more cost-effective than breakd...read more

The procedure for pipe lines welding while route and filling involves several steps.

• Clean the area to be welded thoroughly

• Tack weld the pipes together

• Weld the root pass

• Fill the remaining gap with weld metal

• Perform post-weld heat treatment if required

• Inspect the weld for defects

The interview question covers various topics related to mechanical engineering such as thermodynamics, bearing block size calculation, belt conveyor and bucket elevator types, dial gauge and its parts, crasher types, bearing sleeve, and filler gauge.

• Thermodynamics law

• Calculation of bearing block size

• Types of belt conveyor and bucket elevator

• Dial gauge and its parts

• Crasher types

• Bearing sleeve

• Filler gauge lowest count

The highest temperature in a piston is in the combustion chamber.

• Combustion chamber is where fuel is ignited and burned

• Temperatures can reach up to 2,500 degrees Fahrenheit

• Piston crown is designed to withstand high temperatures

Vehicle parts can be classified into several categories based on their function and location.

• Engine components: pistons, crankshafts, camshafts, valves

• Transmission parts: gears, clutches, driveshafts

• Suspension components: springs, shock absorbers, control arms

• Braking system parts: brake pads, rotors, calipers

• Electrical components: alternators, starters, batteries

• Exhaust system parts: mufflers, catalytic converters, exhaust pipes

• Body and interior parts: doors, windows, seats, ...read more

Yes, I am willing to work at the Budhni plant despite its remote location.

• I am open to relocating for the job

• I have experience working in remote locations

• I am willing to adapt to the new environment and work culture

• I understand the challenges of working in a remote location and am prepared to face them

Bearings are mechanical components that reduce friction between moving parts.

• Bearings support the load and allow for smooth rotation or linear movement.

• They reduce friction and wear between moving parts.

• Bearings come in various types such as ball bearings, roller bearings, and plain bearings.

• Ball bearings use balls to separate the moving parts and are commonly used in applications like motors and wheels.

• Roller bearings use cylindrical or tapered rollers and are suitable for h...read more

Nitrogen gas is commonly used for hot/live tapping in mechanical engineering.

• Nitrogen gas is inert and non-reactive, making it safe to use in hot/live tapping processes.

• It helps to create a protective atmosphere to prevent explosions or fires.

• Nitrogen gas is readily available and cost-effective.

• Other gases like argon or carbon dioxide can also be used depending on the specific requirements.

Draft in a boiler refers to the flow of air or gases through the combustion chamber and flue gas passages.

• Draft is created by a difference in pressure between the inside and outside of the boiler.

• It is necessary for proper combustion and efficient operation of the boiler.

• There are two types of draft: natural draft and forced draft.

• Natural draft is created by the buoyancy of hot gases, while forced draft is created by mechanical means such as fans or blowers.

• Draft can be measu...read more

Enthalpy is the heat content of a system, while entropy is the measure of disorder or randomness in a system.

• Enthalpy is the sum of internal energy and the product of pressure and volume.

• Entropy is the measure of the number of ways energy can be distributed in a system.

• Heat loss in entropy occurs due to the transfer of energy from a hot object to a cold object.

• Entropy always increases in a closed system, leading to a decrease in available energy.

• Enthalpy and entropy are impor...read more

I have used various types of pipes, such as steel, PVC, and CPVC, in previous fire fighting projects.

• Steel pipes are commonly used for their durability and high temperature resistance.

• PVC pipes are lightweight and easy to install, making them suitable for smaller fire fighting systems.

• CPVC pipes are used in areas where higher temperatures are expected, such as boiler rooms or mechanical rooms.

• Examples of fire fighting projects I have worked on include commercial buildings, in...read more

Petrol engines use spark ignition while diesel engines use compression ignition.

• Petrol engines use spark plugs to ignite the fuel-air mixture, while diesel engines rely on compression to ignite the fuel.

• Petrol engines have a higher power-to-weight ratio compared to diesel engines.

• Diesel engines are more fuel-efficient than petrol engines.

• Petrol engines are typically used in cars, motorcycles, and small vehicles, while diesel engines are commonly found in trucks, buses, and he...read more

The question is about mechanical piping execution, equipment used in refinery sector, alignment and installation, pump operation, ASME standards, and fabrication and erection procedures.

• Mechanical piping execution involves the installation and maintenance of piping systems in industrial settings.

• Equipment used in refinery sector includes pumps, compressors, heat exchangers, and boilers.

• Alignment and installation of piping systems is critical to ensure proper functioning and s...read more

Vernier calipers and micrometers are precision measuring tools used in mechanical engineering.

• Vernier calipers are used to measure dimensions with high accuracy, typically up to 0.02 mm.

• Micrometers are used for even more precise measurements, typically up to 0.001 mm.

• Both tools are commonly used in mechanical engineering for dimensional inspection and quality control.

• Vernier calipers have a sliding scale and a main scale, while micrometers have a screw mechanism for measureme...read more

Various methods can be used for railway/road/river crossings depending on the location and other factors.

• Bridges can be built over the crossing

• Tunnels can be dug under the crossing

• Level crossings can be used for roads

• Flyovers can be constructed for roads

• Ferries can be used for river crossings

• Aqueducts can be built for waterways

• Location, traffic volume, and safety considerations must be taken into account when choosing a method

Helical gearboxes are commonly used in the steel industry.

• Helical gearboxes are preferred in the steel industry due to their high efficiency and smooth operation.

• These gearboxes provide better load distribution and reduce noise and vibration.

• They are capable of handling heavy loads and high torque requirements.

• Helical gearboxes are commonly used in steel rolling mills, steel processing plants, and other steel manufacturing equipment.

The least count of vernier calipers is the smallest measurement that can be accurately read on the scale.

• The least count is determined by the number of divisions on the main scale and the vernier scale.

• It is calculated by dividing the smallest division on the main scale by the number of divisions on the vernier scale.

• For example, if the smallest division on the main scale is 0.1 mm and the vernier scale has 10 divisions, the least count would be 0.01 mm.

Earth is the planet where human beings live.

• Human beings live on planet Earth.

• Earth is the third planet from the Sun in our solar system.

• It is the only known planet to support life.

• Earth has a diverse range of ecosystems and environments that sustain human life.

• Examples of Earth's features include oceans, mountains, forests, and deserts.

Fans, blowers, and compressors are all devices used to move air or gas, but they differ in their pressure ratios and flow rates.

• Fans are low-pressure devices that move large volumes of air at low speeds.

• Blowers are medium-pressure devices that move moderate volumes of air at moderate speeds.

• Compressors are high-pressure devices that move small volumes of air or gas at high speeds.

• Fans are commonly used in HVAC systems, cooling towers, and computer cooling.

• Blowers are used in ...read more

Lubrication is necessary for smooth functioning of equipment. Different types of equipment require different lubrication methods.

• Equipment with moving parts require lubrication to reduce friction and wear.

• Oil or grease can be used as lubricants depending on the equipment.

• Lubrication intervals should be followed as per manufacturer's recommendations.

• Examples of equipment that require lubrication include engines, pumps, bearings, and gears.

A diesel generator works by converting diesel fuel into mechanical energy which is then converted into electrical energy.

• Diesel fuel is injected into the combustion chamber where it ignites and creates high pressure gases that push the piston down, creating mechanical energy.

• The mechanical energy is then converted into electrical energy through the use of an alternator.

• The alternator uses a magnetic field and a conductor to generate an electrical current.

• The electrical curren...read more

Inspection is a thorough examination or assessment of a building or equipment to ensure safety and compliance with regulations.

• Inspections involve checking for potential hazards, defects, or violations of codes and standards.

• Inspectors may use tools such as cameras, measuring devices, or testing equipment during the inspection.

• The purpose of an inspection is to identify and address any issues that could pose a risk to safety or health.

• Examples of inspections include fire safe...read more

NGK spark plugs are used in Maruti Suzuki cars.

• Maruti Suzuki uses NGK spark plugs in their cars.

• NGK is a popular brand of spark plugs known for their quality and durability.

• NGK spark plugs are designed to improve fuel efficiency and reduce emissions.

• Other car manufacturers also use NGK spark plugs in their vehicles.

Pascal's law states that pressure applied to a fluid is transmitted equally in all directions. Entropy is a measure of disorder or randomness in a system.

• Pascal's law is important in hydraulic systems, where pressure is used to transmit force.

• Entropy is a thermodynamic property that increases with the degree of disorder in a system.

• Entropy can be used to predict the direction of chemical reactions and the efficiency of energy conversion processes.

Pumps are used to transfer fluids from one place to another, while turbines convert fluid energy into mechanical energy.

• Pumps are used in various applications such as water supply, irrigation, and oil refineries.

• Turbines are commonly used in power generation plants to convert the energy of flowing water, steam, or gas into mechanical energy.

• Pumps and turbines are both types of machines that involve the movement of fluids.

• Pumps generally increase the pressure of the fluid, whi...read more

The theory of failure suitable for ductile materials is the Von Mises criterion, and for brittle materials, it is the Maximum Principal Stress theory.

• Ductile materials undergo plastic deformation before failure, so the Von Mises criterion, which considers the yield strength of the material, is suitable.

• Brittle materials fail suddenly without any plastic deformation, so the Maximum Principal Stress theory, which considers the tensile strength of the material, is suitable.

• Examp...read more

Adiabatic process is a thermodynamic process where no heat is exchanged with the surroundings. Hyperbolic process is a type of adiabatic process.

• Adiabatic process occurs when there is no heat transfer between the system and its surroundings

• Hyperbolic process is a type of adiabatic process where the pressure and volume of a gas are inversely proportional

• Adiabatic compression of a gas can cause an increase in temperature

• Adiabatic expansion of a gas can cause a decrease in tempe...read more

To identify problems in gearbox, fans, and blowers, one can perform visual inspections, listen for abnormal noises, check for vibrations, monitor temperature, and conduct performance tests.

• Perform visual inspections to check for any signs of wear, damage, or leaks.

• Listen for abnormal noises such as grinding, rattling, or whining sounds.

• Check for vibrations in the gearbox, fans, or blowers, which may indicate misalignment or imbalance.

• Monitor temperature levels to ensure they ...read more

The secondary coil resistance in Maruti Suzuki is not publicly available.

• Maruti Suzuki does not disclose the secondary coil resistance of their vehicles.

• The secondary coil resistance can vary depending on the specific model and year of the vehicle.

• It is important for a mechanical engineer to have knowledge of electrical systems in vehicles.

• Secondary coil resistance is a measure of the coil's ability to conduct electricity.

• Other factors that can affect the performance of a coi...read more

Different types of pumps include centrifugal, positive displacement, and axial flow. Sealing systems include mechanical, gland, and magnetic.

• Centrifugal pumps use a rotating impeller to create a flow of fluid. Examples include end-suction, inline, and multistage pumps.

• Positive displacement pumps move fluid by trapping a fixed amount and forcing it through the discharge. Examples include piston, diaphragm, and gear pumps.

• Axial flow pumps move fluid parallel to the axis of rota...read more

20 alternative uses of a stapler

• As a makeshift hole puncher

• To hold together a broken necklace chain

• To create a makeshift zipper pull

• To create a makeshift lock for a door

• To create a makeshift weight for a fishing line

• To create a makeshift needle for sewing

• To create a makeshift screwdriver

• To create a makeshift zipper repair tool

• To create a makeshift paper clip

• To create a makeshift zipper stopper

• To create a makeshift zipper slider

• To create a makeshift zipper puller

• To create a ma...read more

The Pacific Ocean is the largest ocean in the world.

• The Pacific Ocean covers an area of about 63 million square miles.

• It is larger than all the other oceans combined.

• It stretches from the Arctic Ocean in the north to the Southern Ocean in the south.

• The Pacific Ocean is home to numerous islands, including Hawaii and Easter Island.

To identify a problem in a running machine bearing, one can listen for abnormal noises, check for excessive vibration, monitor temperature, and inspect for wear or damage.

• Listen for abnormal noises such as grinding, squeaking, or knocking sounds.

• Check for excessive vibration in the machine or bearing housing.

• Monitor the temperature of the bearing using an infrared thermometer or thermal imaging camera.

• Inspect the bearing for signs of wear, such as pitting, scoring, or discolo...read more

The engine oil capacity varies depending on the make and model of the vehicle.

• Engine oil capacity can be found in the owner's manual or by contacting the manufacturer.

• It is important to use the correct amount of oil to ensure proper lubrication and prevent damage to the engine.

• Overfilling or underfilling the oil can lead to engine problems.

• Some vehicles may require more oil for larger engines or for towing purposes.

IDU and ODU are abbreviations used in air conditioning systems. IDU stands for Indoor Unit and ODU stands for Outdoor Unit.

• IDU is the unit that is installed inside the room or building, while ODU is installed outside.

• IDU is responsible for cooling or heating the air inside the room, while ODU is responsible for dissipating the heat outside.

• IDU is connected to ODU through refrigerant pipes and electrical cables.

• Examples of IDU include wall-mounted units, ceiling cassette units...read more

During zero break in the plant, we perform routine maintenance tasks and inspections to ensure smooth operations.

• Performing equipment checks and maintenance

• Inspecting and repairing any mechanical issues

• Calibrating and adjusting machinery

• Conducting preventive maintenance

• Updating maintenance logs and documentation

Couplings are used to connect two shafts together. The type of coupling used depends on the application.

• Flexible couplings are used to compensate for misalignment between shafts.

• Rigid couplings are used when shafts are perfectly aligned.

• Gear couplings are used for high torque applications.

• Jaw couplings are used for low to medium torque applications.

• Disc couplings are used for high-speed applications.

• Chain couplings are used for applications with large distances between shafts...read more

Expected CTC should be discussed during the interview process.

• It is important to research industry standards and company salary ranges before giving a number.

• Consider the job responsibilities, experience, and qualifications when determining expected CTC.

• Be open to negotiation and understand the company's benefits package.

• Avoid giving a specific number too early in the interview process.

• Instead, ask about the company's salary range and discuss expectations.

• Example: Based on my...read more

Duplex stainless steel is good for NaCl 2500 ppm fluid due to its high corrosion resistance and strength.

• Duplex stainless steel has a high resistance to corrosion and pitting

• It has a high strength and toughness

• Other materials like carbon steel and copper alloys may corrode in NaCl solutions

I may have theoretical knowledge only, but I am a quick learner and willing to work hard to gain practical experience.

• I am eager to learn and willing to put in extra effort to gain practical experience.

• I have a strong foundation in theoretical knowledge, which can be applied to real-world situations.

• I am a quick learner and can adapt to new situations easily.

• I am open to feedback and willing to learn from my mistakes.

• I am a team player and can work collaboratively with experi...read more

Diesel engines are commonly used in trains.

• Trains typically use diesel engines due to their high torque and fuel efficiency.

• Electric engines are also used in some trains, especially in urban areas.

• Steam engines were used in the past but are now rare.

• Hybrid engines that combine diesel and electric power are becoming more common.

• The type of engine used in a train depends on factors such as the distance it travels and the terrain it covers.

Sewage treatment plants involve chemical, mechanical, and electrical processes.

• Chemical processes involve the use of chemicals to remove contaminants from the sewage.

• Mechanical processes involve physical methods like screening, sedimentation, and filtration to remove solids and other impurities.

• Electrical processes involve the use of electrical equipment like pumps and motors to move sewage through the treatment plant.

• Examples of processes include activated sludge process, tr...read more