Fundamentals Flashcards

Which nondestructive examination (NDE) method is most effective for detecting subsurface volumetric discontinuities in a weld?

Answer: Radiographic testing (RT)

Radiographic testing uses X-rays or gamma rays to reveal internal volumetric flaws such as porosity and inclusions throughout the weld cross-section.

A weld symbol with a circle at the intersection of the reference line and arrow indicates:

Answer: A weld all around

A circle placed at the junction of the reference line and arrow on a weld symbol signifies that the weld is to be made all around the joint.

What is the primary purpose of using shielding gas in GMAW?

Answer: To protect the molten weld pool from atmospheric contamination

Shielding gas in GMAW surrounds the arc and weld pool to prevent oxygen, nitrogen, and moisture from contaminating the molten metal.

In the context of welding procedure qualification, what does 'essential variable' mean?

Answer: A variable whose change requires re-qualification of the welding procedure

An essential variable is one whose change beyond specified limits is considered to affect the mechanical properties and requires re-qualification of the WPS.

Which destructive test is used to evaluate the ductility and soundness of a weld by bending the specimen?

Answer: Guided bend test

The guided bend test bends a weld specimen around a mandrel to a specified angle, revealing lack of fusion, cracks, or porosity on the tension surface.

Electrode classification E7018 indicates a minimum tensile strength of:

Answer: 70,000 psi

The first two digits '70' in E7018 indicate a minimum tensile strength of 70,000 psi (70 ksi) for the deposited weld metal.

What is 'undercut' in a weld?

Answer: A groove melted into the base metal along the weld toe that is not filled

Undercut is a groove burned into the base metal at the toe or root of a weld that is left unfilled by weld metal.