Fracture prediction of corroded ZG300-500H cast steel with micromechanical fracture model

Abstract

The effects of corrosion on the fracture prediction of steel are investigated. The power function for cast steel ZG300-500H in the acetic acid salt spray corrosion environment is fitted to illustrate the acceleration of the acetic acid salt spray corrosion test, and the statistical characteristics of the pit depth and pit diameter-depth ratio are analyzed. The material parameters of micromechanical fracture model under monotonic load are calibrated by tensile test and finite element analysis on smooth-notch tensile specimens. The VGM model and SMCS model can also be applied to predict the fracture of corroded ZG300-500H cast steel based on the random distribution model of corrosion pits. The finding is that the crack of the non-corroded single-notch specimens always initiates from the centre of the critical cross section. Corroded specimen cracks initiate from the severe corrosion areas. Once a crack is initiated, it always extends along the thickness and forms a visible crack. The subsequent crack propagation along the width direction can be simulated accurately.