12th International Conference on Zinc & Zinc Alloy Coated Steel Sheet - GALVATECH 2021

Global expansion of automotive market leads to demand for optimization of materials selection corresponding to the corrosion severity in environments. Although great efforts have been devoted to study the corrosion behaviour of steel products in East and Southeast Asia, reports concerning corrosion occurring in the automotive body in those regions are still quite limited to the date. Atmospheric corrosion and corrosion occurring in automotive bodies in these regions are considered to be relatively mild compared to those in de-icing salt deposited area like North America or North Europe because of lower salinity. However, it is pointed out recently that corrosion-rate estimating formula advocated by ISO may underestimate the corrosion rate in the Asian regions, and actual corrosion data of automotive materials correlated with environmental factors have been largely demanded. In this paper, results of short-term (2 years) atmospheric exposure tests of several automotive body materials such as cold rolled steel sheets (CRS) and zinc coated steel sheets demonstrated at exposure sites located in Japan and Indonesia will be presented. In addition to bare (unpainted) panels, test pieces which simulate automotive body are studied, and their corrosion behaviours are analysed by using physical analytical techniques like X-ray diffraction (XRD), Scanning electron microscopy (SEM) and energy-dispersive X-ray spectroscopy (EDX). Relationship between corrosion behaviours of iron, zinc or zinc alloys and environmental factors will also be discussed.