Study on corrosion models of structural steel exposed in urban industrial atmospheric and laboratory simulated environments based on the 3D profile

The time-dependent safety assessment and reliability analysis of a structure depends primarily on the corrosion model that directly affects the calculation accuracy. The three-dimensional non-contact surface topography instrument was used to study the corrosion morphology under urban industrial atmospheric exposure conditions and the dry/wet cycle accelerated corrosion test. The evaluation indices of the proposed corrosion model were study, including pit shape, pit depth, pit diameter–depth ratio, etch pit distribution, and thickness. Time-dependent mathematical models between these parameters and the corrosion degree are discussed. The pit depth distribution follows the normal distribution and a probability distribution model related to the rust ratio is established. There is a certain relationship between the thickness loss and etch pit depth. A corrosion model suitable for the common Q235 steel used in civil engineering in an acid rain corrosion environment is proposed. The applicability of the corrosion model is verified through the machine-simulated corrosion on the same batch of structural steel.