Lap-Joint Corrosion Testing of Precoated Steel Sheets

Abstract

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, organic) 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 know the behaviour 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 galvanised, painted and unpainted) and car manufacturing (electrogalvanised and galvanneal).