Aluminum Hot Cracking Susceptibility During Welding
Aluminum tends to hot cracking during welding, especially when residual liquid films remain at the grain boundaries. Unfavorable alloys increase the risk.
Physico-chemical mechanism of action
Aluminum has a low stress limit and forms residual liquid films at the grain boundaries at low temperatures. These films can lead to cracks during cooling if not completely removed.
Metallurgical relevance & risks during welding
Unfavorable aluminum alloys increase the tendency to hot cracking. The residual liquid films can lead to glassy structures that are prone to cracking. This can lead to damage and loss of component integrity.
Workshop practice & action instructions
When welding aluminum, ensure high purity of the weld metal and correct cooling systems. Remove residual liquid films thoroughly after welding, e.g., by polishing or chemical cleaning. Keep the temperature constant during cooling and avoid rapid temperature drops.