Fundamentals Tech Flashcards

Which type of weld discontinuity is described as a groove melted into the base metal adjacent to the weld toe?

Answer: Undercut

Undercut is a groove or channel melted into the base metal at the weld toe, reducing the effective throat and creating a stress concentration.

What is the significance of the 'A number' classification in AWS filler metal standards?

Answer: Classifies deposited weld metal chemical composition

The A-number system classifies deposited weld metal according to chemical composition, primarily used for stainless steel and alloy filler metals.

During visual inspection, a CWI finds a crater crack at the end of a weld. What is the most likely cause?

Answer: Improper termination of the arc without filling the crater

Crater cracks form when the arc is extinguished abruptly, leaving an unfilled, rapidly cooling crater that cracks as it shrinks.

Which AWS electrode classification represents a low-hydrogen SMAW electrode?

Answer: E7018

E7018 is a low-hydrogen electrode (indicated by the '8' suffix), requiring controlled storage to prevent moisture absorption.

What is the function of the flux coating on an SMAW electrode?

Answer: To provide shielding gas, deoxidizers, and slag for weld protection

The flux coating generates shielding gases to protect the molten weld pool, provides deoxidizers, and forms a slag blanket that protects the solidifying weld.

When checking a fillet weld with a fillet weld gauge, what dimension is being verified?

Answer: Leg size and throat dimension

A fillet weld gauge measures the leg size and can also be used to estimate the theoretical throat of a fillet weld.

Which of the following is an example of a 'planar' weld discontinuity?

Answer: Lack of fusion

Lack of fusion is a planar discontinuity because it lies in a plane — the unfused interface between weld metal and base metal — making it most severe under loading.