National Petroleum Construction Company Pipe Fabricator Interview Questions and Answers

The pipe is injected with argon gas before welding to create an inert atmosphere.

• Before welding, the pipe is purged with argon gas to remove any oxygen and moisture that could contaminate the weld.

• This is typically done using a purge gas system that fills the pipe with argon and then vents it out before welding.

• Purging with argon helps prevent oxidation and ensures a clean, strong weld.

• Proper purging techniques are ess...read more

Metals such as stainless steel, carbon steel, and aluminum are commonly used before the welding process.

• Stainless steel is often used for its corrosion resistance and durability.

• Carbon steel is commonly used for its strength and affordability.

• Aluminum is lightweight and has good conductivity, making it suitable for certain applications.

Dimensions of the elbow of unknown degree are calculated using trigonometry and geometry.

• Calculate the centerline radius of the elbow.

• Use trigonometry to find the length of the elbow.

• Consider the angle of the elbow to determine the dimensions.

• Measure the outside diameter and wall thickness of the pipe for accurate calculations.

Isometric drawing is a 3D drawing that represents a 3D object in 2D with the use of angles and measurements.

• Isometric drawing is a type of pictorial drawing that shows three faces of an object in one view.

• It is drawn using 30-degree angles to represent the object in 3D.

• Isometric drawings are commonly used in engineering and construction to show the details of piping systems, buildings, and machinery.

• The degree of an is...read more

The center of a 24-inch pipe elbow is the point where the centerline of the pipe intersects with the centerline of the elbow.

• The center of the elbow is where the centerline of the pipe intersects with the centerline of the elbow

• The center of the elbow is important for proper installation and alignment

• The center of the elbow can be calculated using mathematical formulas or measured using specialized tools

A transformer is a device that transfers electrical energy between two or more circuits through electromagnetic induction.

• Transformers are used to increase or decrease voltage levels in electrical circuits.

• They consist of primary and secondary coils wound around a core made of ferromagnetic material.

• Step-up transformers increase voltage for long-distance power transmission, while step-down transformers decrease voltage...read more