Stress corrosion cracking (molten metal induced) | hot-dip galvanisation

In the present case, a hot-dip galvanized screw of a wind turbine is involved. With the aid of backscattered electron contrast and EDS analysis, concentrated contents of Sn and Pb were detected in incipient cracks under the zinc coating. Molten metal induced stress corrosion cracking is the term used to describe a solder brittleness that leads to embrittlement in the presence of high mechanical and/or thermal stresses in a component due to contact with a molten metal (e.g. during galvanizing). This loss of ductility leads either to smaller incipient cracks in the base material, which are generally hidden by the metallic coating, or directly to large, macroscopically visible cracks in the component.