Visual Testing (VT) Practice Exam

A slag-type discontinuity is typically produced by which process?

1. SMAW

2. GTAW

3. GMAW

4. Brazing

The correct answer is: SMAW

A slag-type discontinuity is primarily produced during the Shielded Metal Arc Welding (SMAW) process. This welding technique involves using a consumable electrode coated with flux, which generates slag as a byproduct when the electrode melts during welding. The flux creates a protective layer that prevents oxidation and contamination, but after the welding process, the solidified slag can become trapped in the weld, leading to the discontinuity known as slag inclusion. Other welding processes listed, such as Gas Tungsten Arc Welding (GTAW) and Gas Metal Arc Welding (GMAW), do not typically produce slag-type discontinuities because they do not involve a slag-forming flux. Instead, these processes result in clean welds with fewer contaminants. Brazing, on the other hand, is a joint-filling process that uses a filler metal at a temperature above 450 °C without melting the base metals, so it does not create slag either. Therefore, SMAW's unique characteristic of generating slag during the welding process makes it the correct choice for producing slag-type discontinuities.