During the welding of a low-carbon steel pipe, the supervisor observes excessive spatter and inconsistent bead appearance despite using the correct voltage and amperage settings for the process. Upon inspection, the shielding gas regulator shows a flow rate of 5 L/min for a GMAW process. What is the most likely cause of the issue?

Question: During the welding of a low-carbon steel pipe, the supervisor observes excessive spatter and inconsistent bead appearance despite using the correct voltage and amperage settings for the process. Upon inspection, the shielding gas regulator shows a flow rate of 5 L/min for a GMAW process. What is the most likely cause of the issue?

Answer options:

• The travel speed is too slow. ✅ The shielding gas flow rate is insufficient.
• The electrode extension (stick-out) is too short.
• The base metal has excessive mill scale.

Correct answer: The shielding gas flow rate is insufficient.

Explanation: An insufficient shielding gas flow rate of 5 L/min for GMAW can lead to poor gas coverage, resulting in atmospheric contamination, excessive spatter, and an unstable arc. While other factors can affect bead appearance, inadequate shielding is a direct cause of spatter and porosity. Proper shielding gas flow for GMAW typically ranges from 10 to 20 L/min, depending on the application.