Lap-Joint Corrosion Testing Of Precoated Steel Sheets

By Belén Chico, Daniel de la Fuente, Manuel Morcillo, José Antonio González, Eduardo Otero

In industry, and particularly in the building construction and automotive industries, lap-joint technology for precoated steel sheet assembly has undergone rapid development. However, the durability problems associated with joints of this type are well known, i.e., premature deterioration of protective coatings (metallic, organ-ic) and accelerated metallic corrosion of the base steel by moisture retention in the joint, crevice corrosion, etc.

The authors have been involved in researching lap-joint corrosion testing to learn the behavior of materials in these joints. The precoated steel sheet materials studied were divided into two groups according to their use in two well-defined industrial sectors: building (55% Al-Zn and hot-dip galvanized, painted and unpainted) and car manufacturing (electro-galvanized and galvanneal).