In order to evaluate the effects of durability, in terms of corrosion, on a polymer-metal joint, hygrothermal aging at different conditions was conducted in a polymer-metal composite, which consists of a steel substrate, with and without corrosion protection; a polyester-based adhesive coating; and on top, an overmolded thermoplastic urethane. The hygrothermal aging test was carried out for 1000 hours at a relative high temperature and low humidity, 85 °C/40 %rH; at harsh conditions, 85 °C/85 %rH; and simulating a common tropical weather, 40 °C/90 %rH. After the artificial aging, the influence of temperature and humidity on corrosion and, subsequently, the failure modes of the composite, were investigated by digital microscopy, SEM/XDS, DSC/TGA and mechanical test.