Certified Welder Welding Processes and Equipment 3

Question 1

What is the primary advantage of using DCEN (straight polarity) in SMAW?

Accepted Answer

Greater heat at the electrode, less at the base metal

Answer

DCEN directs more heat to the electrode end rather than the base metal, which can be useful for specific electrodes and thin materials.

Question 2

Which GMAW transfer mode produces the least spatter and is characterized by very small droplets transferred across the arc?

Accepted Answer

Spray transfer

Answer

Spray transfer uses high voltage and amperage to project tiny droplets axially across the arc with minimal spatter.

Question 3

What is the function of the contact tip in a GMAW welding gun?

Accepted Answer

It transfers welding current to the wire electrode

Answer

The contact tip conducts welding current to the continuously fed wire electrode as it passes through the tip.

Question 4

In resistance spot welding, what creates the heat needed to fuse the metal?

Accepted Answer

Electrical resistance at the interface when current flows through the parts

Answer

Resistance spot welding generates heat through the electrical resistance at the contact point between workpieces when high current is applied.

Question 5

Which shielding gas mixture is most commonly used for GMAW of carbon steel with spray transfer?

Accepted Answer

75% Argon / 25% CO2

Answer

A 75% Ar / 25% CO2 mixture (C25) is the most common blend for GMAW of carbon steel, providing good arc stability and penetration.

Certified Welder Practice Test