What is one of the primary causes of porosity in GTAW?

What is one of the primary causes of porosity in GTAW?

• A. Oxygen pickup
• B. Hydrogen pickup
• C. Moisture contamination
• D. Excessive heat

Answer: (B)

Hydrogen pickup is a primary cause of porosity in Gas Tungsten Arc Welding (GTAW) due to the nature of the welding process and the materials involved. During GTAW, if the welding atmosphere is contaminated with hydrogen, it can dissolve into the molten weld pool. As the weld cools and solidifies, the hydrogen can come out of solution and form gas pockets, leading to porosity. Control of hydrogen is crucial, especially when welding materials that are sensitive to hydrogen, such as stainless steels and high-strength steels. The presence of hydrogen can result from various sources, including surface contaminants like oils and grease or even the base material if it has absorbed moisture. Understanding the impact of hydrogen on weld quality helps welders take the necessary precautions, such as ensuring the material is clean and dry before welding. It emphasizes the importance of the welding environment and the composition of the filler material, which should be chosen carefully to minimize hydrogen content.

Hydrogen pickup is a primary cause of porosity in Gas Tungsten Arc Welding (GTAW) due to the nature of the welding process and the materials involved. During GTAW, if the welding atmosphere is contaminated with hydrogen, it can dissolve into the molten weld pool. As the weld cools and solidifies, the hydrogen can come out of solution and form gas pockets, leading to porosity.

Control of hydrogen is crucial, especially when welding materials that are sensitive to hydrogen, such as stainless steels and high-strength steels. The presence of hydrogen can result from various sources, including surface contaminants like oils and grease or even the base material if it has absorbed moisture.

Understanding the impact of hydrogen on weld quality helps welders take the necessary precautions, such as ensuring the material is clean and dry before welding. It emphasizes the importance of the welding environment and the composition of the filler material, which should be chosen carefully to minimize hydrogen content.