Piping Pipe Welding and Fabrication 3

Question 1

What does 'weld map' refer to in pipe fabrication?

Accepted Answer

A drawing showing the location of all welds on a pipe spool with unique weld identification numbers

Answer

A weld map is a drawing that identifies and numbers every weld on a pipe spool, allowing traceability to the welder, procedure, inspection results, and PWHT records.

Question 2

Which type of weld discontinuity is typically caused by incorrect travel speed or arc length during pipe welding?

Accepted Answer

Undercut

Answer

Undercut is a groove melted into the base metal adjacent to the weld toe, usually caused by excessive current, incorrect angle, or too high travel speed.

Question 3

What is the significance of a welder's 'coupon test' in qualifying to ASME Section IX?

Accepted Answer

It produces a test weld that is mechanically tested to verify the welder can produce sound welds within specified essential variables

Answer

The coupon (qualification test) weld is destructively tested (bend tests, visual) to verify the welder produces welds with acceptable mechanical properties and soundness.

Question 4

In pipe fabrication, what does 'fit-up' mean?

Accepted Answer

The alignment and positioning of pipe components before welding

Answer

Fit-up is the process of aligning and positioning pipe, fittings, and flanges prior to tacking and welding to ensure dimensional accuracy and proper joint geometry.

Question 5

What is 'hi-lo' in pipe welding terminology?

Accepted Answer

The mismatch in inner diameter alignment between two pipe ends being joined

Answer

Hi-lo (or internal misalignment) is the offset between the inside surfaces of two pipe ends at a butt weld, which creates stress concentration and reduces weld quality.

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Piping Pipe Welding and Fabrication 3