Analysis of Strength Degradation of Q235 Corroded Steel Based on Pitting Evolution

Abstract

Proposes To evaluate the strength degradation behavior of corroded steel with pitting evolution, an in-situ pitting evolution method is achieved by ABAQUS software combined with Python program according to pit statistics on steel matrix surfaces at different corrosion durations. Following this, the stochastic pitting evolution method for assessing the mechanical properties of corroded steel is proposed. Methods Then, on the premise of the consistent mass loss rates between the numerical model and the test, the accuracy and applicability of numerical results of corroded steel strength are analysed and verified. Also, a model of strength degradation created by corrosion pits is established. In addition, the degradation laws of yield and ultimate strengths of corroded Q235 steel under the joint influence of mass loss rate and corrosion depth are systematically investigated. Successively, the generalized equations for the evolution of yield and ultimate strengths of corroded steel with the mass loss rate and corrosion depth are proposed. Findings The results show that when the pit depth is known, the residual strength decreases exponentially with the increase of mass loss rate. The yield strength and ultimate strength of steel under the influence of pitting corrosion can be calculated by mass loss rate and pit depth together.

Keywords

• corroded steel
• pitting evolution
• residual strength
• mass loss rate
• stochastic numerical analysis