L&T Energy Hydrocarbon Assistant Manager and Mechanical Engineer Interview Questions, Process, and Tips

I have designed and implemented piping systems for various industrial projects.

• Designed piping layouts for new construction projects

• Analyzed existing piping systems for efficiency and made recommendations for improvements

• Collaborated with other engineers and contractors to ensure proper installation and functionality

• Performed stress analysis on piping systems to ensure safety and reliability

There are various types of drawings used in engineering, including mechanical drawings, architectural drawings, electrical drawings, and civil drawings.

• Mechanical drawings: used to illustrate mechanical components and systems

• Architectural drawings: used to show the layout and design of buildings

• Electrical drawings: used to depict electrical systems and wiring

• Civil drawings: used for infrastructure projects like roads a

LPD and HPV play a crucial role in controlling pressure and flow in pipelines, ensuring efficient operation and preventing damage.

• LPD (Low Pressure Drop) valves help reduce pressure loss in pipelines, improving efficiency and reducing energy consumption

• HPV (High Pressure Valve) valves are used to control high pressure flow in pipelines, preventing damage and ensuring safety

• Installation in line ensures that LPD and HPV ...read more

Tests in piping are decided based on factors like material, pressure, temperature, and intended use.

• Consider the material of the piping (e.g. steel, PVC) to determine appropriate tests.

• Take into account the pressure and temperature the piping will be subjected to.

• Identify the intended use of the piping (e.g. water supply, gas distribution) to select relevant tests.

• Common tests include hydrostatic testing, pneumatic tes

Typically, multiple gauges are provided during hydro testing to monitor pressure and ensure safety.

• Multiple gauges are provided during hydro testing to monitor pressure at different points.

• Common gauges used include pressure gauges, temperature gauges, and flow meters.

• The number of gauges provided can vary depending on the size and complexity of the system being tested.

• For example, a hydro test on a large industrial pi...read more

The dropping pressure at the highest point gauge during hydro testing is due to the natural phenomenon of hydrostatic head pressure.

• Hydrostatic head pressure decreases as the height of the fluid column decreases.

• The pressure at the highest point gauge will be lower compared to the pressure at the bottom of the system.

• This drop in pressure is expected and is a normal occurrence during hydro testing.

• Factors such as eleva...read more

SS304 is a basic stainless steel alloy with 18% chromium and 8% nickel, while SS316 has 16% chromium, 10% nickel, and 2% molybdenum.

• SS304 is more commonly used for general applications due to its lower cost and good corrosion resistance.

• SS316 is preferred for applications where higher corrosion resistance is required, such as in marine environments or chemical processing plants.

• SS316 is also more resistant to pitting a...read more

SS304 contains 18% chromium and SS316 contains 16-18% chromium.

• SS304 contains 18% chromium

• SS316 contains 16-18% chromium

• Chromium content in stainless steel enhances its corrosion resistance

ER308 and ER316 filler rods are commonly used in SS304 and SS316 respectively.

• ER308 filler rod is used for welding SS304 stainless steel

• ER316 filler rod is used for welding SS316 stainless steel

A106 GRB is a specification for seamless carbon steel pipe for high-temperature service.

• A106 GRB is a grade of seamless carbon steel pipe.

• It is specifically designed for high-temperature service.

• It is commonly used in industrial applications such as oil and gas processing.

• A106 GRB pipes are known for their strength and durability.

I have worked on pipes ranging from 2 inches to 24 inches in diameter.

• Worked on various pipe sizes including 2 inches, 4 inches, 6 inches, 8 inches, 12 inches, and 24 inches

• Experience with both small and large diameter pipes

• Skilled in handling different types of pipe materials such as PVC, steel, and copper

Filler material: E9015-B9, Electrode: E9018-B9

• Filler material for P91 is typically E9015-B9

• Electrode used for welding P91 is usually E9018-B9

During fittup and welding of P91, preheating and post-weld heat treatment are crucial steps to prevent cracking and ensure proper weld quality.

• Preheating of P91 material to a specific temperature range before welding to reduce the risk of cracking

• Maintaining interpass temperature during welding to prevent rapid cooling and cracking

• Post-weld heat treatment of the welded joint to relieve residual stresses and ensure prop...read more

Filler metal and electrodes used in P5 are typically low alloy steel materials.

• Filler metal: Low alloy steel filler metals are commonly used in welding P5 materials.

• Electrodes: Low hydrogen electrodes are preferred for welding P5 due to their high strength and crack resistance.

• Examples: ER80S-D2 filler metal, E8018-B2 electrode

Preheat temperature and cycles are important factors in mechanical engineering processes.

• Preheat temperature refers to the temperature at which a material or component is heated before further processing.

• Preheat cycles are the number of times a material or component is heated and cooled before the final processing step.

• Preheating helps reduce thermal shock, improve weld quality, and prevent cracking in materials.

• Exampl...read more

Postheat temperature and cycles refer to the temperature and number of heating and cooling cycles applied to a material after welding to relieve stress and prevent cracking.

• Postheat temperature is typically around 200-400 degrees Fahrenheit for carbon steels

• Postheat cycles involve heating the material to the specified temperature and holding it for a specific amount of time before allowing it to cool slowly

• Postheat tre...read more

Concentric reducers are preferred for cost-effective reduction in pipe size, while eccentric reducers are used when maintaining the same level is important.

• Concentric reducers are used when the center lines of the larger and smaller pipes are to be aligned.

• Eccentric reducers are used when maintaining the same level is important, such as in drainage systems.

• Concentric reducers are more cost-effective compared to eccentr...read more

ECC reducer should be used in pump suction line to reduce turbulence and improve pump efficiency.

• ECC reducer helps in reducing turbulence in the pump suction line

• It helps in improving pump efficiency by reducing pressure drop

• It prevents cavitation in the pump which can damage the pump over time

The voltage of light used in confined spaces varies depending on the specific lighting fixture and safety regulations.

• The voltage of light used in confined spaces can range from 12 volts for low voltage lighting to 120-277 volts for standard lighting fixtures.

• In some cases, special low voltage lighting may be required for safety reasons in confined spaces.

• It is important to follow safety regulations and guidelines when...read more

I recently led a team in designing and implementing a new automated assembly line for a manufacturing company.

• Managed a team of engineers and technicians to develop project timeline and budget

• Designed layout of assembly line to optimize efficiency and productivity

• Implemented automated machinery and conducted testing to ensure functionality

• Collaborated with production staff to train on new equipment and processes

Support is typically provided up to 50 feet in a 1.5 inch line.

• Support is usually provided every 6-8 feet in a 1.5 inch line to prevent sagging or stress on the line.

• Support can be in the form of clamps, brackets, or hangers depending on the specific installation requirements.

• Proper support ensures the line remains secure and stable, preventing leaks or damage.

• For example, in a industrial setting, a 1.5 inch steam line...read more

JSA stands for Job Safety Analysis. It is used to identify and control hazards in the workplace.

• JSA is a systematic process for identifying potential hazards in a job task or process.

• It involves breaking down the task into steps, identifying potential hazards at each step, and implementing controls to mitigate those hazards.

• JSA helps in preventing accidents and injuries by ensuring that workers are aware of the risks a...read more

The first steps in taking responsibility for piping involve conducting a thorough assessment, creating a plan, and ensuring compliance with regulations.

• Conduct a thorough assessment of the current piping system to identify any issues or areas for improvement

• Create a detailed plan outlining the necessary steps to address any identified issues and improve the piping system

• Ensure compliance with relevant regulations and s...read more

The amount of welding done by a welder in a shop and field varies depending on the project and requirements.

• The amount of welding done by a welder can range from a few inches for small projects to several feet for larger projects.

• In a shop setting, a welder may typically work on smaller pieces requiring less welding compared to field work which may involve larger structures.

• Factors such as the type of welding process u...read more

To cross check piping missing components, use piping and instrumentation diagrams (P&IDs), conduct physical inspections, compare with design specifications, and use 3D modeling software.

• Refer to piping and instrumentation diagrams (P&IDs) to identify all components in the piping system

• Conduct physical inspections of the piping system to visually check for missing components

• Compare the actual piping layout with the desi...read more

Yes, S316 fittings can be used in S304 applications.

• S316 fittings can be used in S304 applications due to their similar corrosion resistance properties.

• Both S316 and S304 are austenitic stainless steels, so they are compatible for most applications.

• However, it is important to consider the specific requirements of the application before using S316 fittings in S304 systems.