AWS Welding Inspection and Testing Certification Practice Test

Which welding process is most likely to have slag inclusions?

1. GMAW

2. SMAW

3. GTAW

4. OAW

The correct answer is: SMAW

The welding process most likely to encounter slag inclusions is Shielded Metal Arc Welding (SMAW). This is due to the characteristics of the welding process itself. In SMAW, a coated electrode produces a shielding gas and a layer of slag when it melts. The slag serves to protect the molten weld pool from atmospheric contamination during the welding process. However, if the slag is not removed properly or if the user does not maintain an appropriate technique, slag can become trapped within the weld. This can lead to slag inclusions, which are detrimental to weld quality as they can create weak spots, reduce weld strength, and lead to premature failure of welded components. Other processes, such as Gas Metal Arc Welding (GMAW) and Gas Tungsten Arc Welding (GTAW), do not typically produce slag in the same way. GMAW uses a continuous wire feed and relies on a shielding gas that does not create a slag layer, thereby minimizing the risk of inclusions. GTAW, which uses a non-consumable tungsten electrode, similarly does not generate slag. Oxygen-acetylene welding (OAW) primarily uses a flame and does not generate slag as SMAW does, further reducing the risk of slag inclusions in that process