Repassivation Rate
The speed at which a damaged passive layer is restored. A high value means quick restoration and better corrosion protection.
Physicochemical Mechanism of Action
Repassivation rate describes how quickly a damaged passive layer on a metal is restored. This process involves the transformation of active metal into passive metal through chemical reactions with the environment.
Metallurgical Relevance & Welding Risks
A high repassivation rate is important because it improves corrosion protection and extends material life. However, a value that is too low can cause the passive layer to recover slowly, leading to increased corrosion.
Workshop Practice & Instructions
To ensure an optimal repassivation rate, it is important that the weld cools correctly. Cooling too fast (t8/5 < 5 s) can prevent the passive layer from recovering quickly enough. Cooling too slowly (t8/5 > 25 s) can cause excessive grain coarsening and reduced corrosion protection.