Dezincification
Dezincification is a corrosion phenomenon in brass alloys where zinc is leached out, leaving a porous copper skeleton. This leads to a significant loss of strength.
Physical-Chemical Mechanism of Action
During dezincification, zinc in brass reacts with oxygen and water vapor in the weld pool, causing it to dissolve out of the alloy. The remaining copper forms a porous skeleton that is mechanically unstable.
Metallurgical Relevance & Risks in Welding
Dezincification causes a drastic loss of strength in the brass component. This can lead to cracks and deformation under mechanical stress.
Workshop Practice & Instructions
To avoid dezincification, ensure the weld pool is well covered to exclude water vapor and oxygen. Clean the weld thoroughly after welding to remove zinc residues. For brass alloys, it’s advisable to do a short post-treatment with a suitable deoxidizer.