Moisture and dirt on the surface of the wire electrode is likely to cause which defect?

Moisture and dirt on the surface of the wire electrode is likely to cause which defect?

• A. Porosity.
• B. Cold Lap.
• C. Electrical Shock.
• D. Post-Weld Stress Cracking.

Answer: (A)

Moisture on the electrode surface introduces hydrogen into the weld as it heats, and hydrogen tends to form tiny gas pockets in the molten metal as it cools and solidifies. Those trapped gas pockets show up as porosity in the final weld. Dirt or oxide on the wire can also contaminate the weld surface and disrupt shielding, promoting gas entrapment and inclusions that contribute to porosity. The shielding gas is meant to keep air out, so any moisture or dirt on the electrode undermines that protection and makes porosity more likely. Other defects aren’t as directly caused by surface moisture or dirt on the electrode in this scenario.

Moisture on the electrode surface introduces hydrogen into the weld as it heats, and hydrogen tends to form tiny gas pockets in the molten metal as it cools and solidifies. Those trapped gas pockets show up as porosity in the final weld. Dirt or oxide on the wire can also contaminate the weld surface and disrupt shielding, promoting gas entrapment and inclusions that contribute to porosity. The shielding gas is meant to keep air out, so any moisture or dirt on the electrode undermines that protection and makes porosity more likely. Other defects aren’t as directly caused by surface moisture or dirt on the electrode in this scenario.