Aluminum Weld Seam Porosity
Aluminum weld porosity is caused by water vapor in the melt, which condenses into hydrogen gas during cooling and forms pores. Careful joint preparation is essential.
Physical-Chemical Mechanism of Action
Hydrogen dissolves very well in aluminum melt. As solubility decreases during cooling, hydrogen gas condenses and forms pores in the solidified state.
Metallurgical Relevance & Risks in Welding
Porosity leads to reduced strength and toughness of the weld, affecting mechanical properties. It can also cause cracks and deformation, especially under load.
Shop Practice & Instructions
• Joint Preparation: Ensure the weld area is clean and free of dirt particles or paints. Use a thorough cleaning method.
• Melting Conditions: Keep the melting temperature constant and avoid rapid temperature changes to minimize water vapor formation.
• Cooling Protection: Use a shielded cooling process, e.g., through a closed welding gas loop or a suitable cooling agent, to prevent porosity.