Experimental Study on Fatigue Crack Growth of Precorroded High-Strength Steels

To investigate the fatigue crack growth behavior of precorroded high-strength steels, a salt spray corrosion test using compact tension specimens made of Q460C, Q550D, and Q690D is conducted, and the corrosion rate is studied by mass losses and surface roughness. The effect of precorrosion on fatigue crack growth behavior is discussed based on a fatigue crack growth test by comparing fitted material constants in the Paris law and the strain energy density factor equation with those in related literature and design codes. A prediction model to predict material constants with longer exposure time is proposed. The results show that corrosion pit depth and surface roughness generally increase with the increase in exposure time; The parameters, m and n, show a generally gradual decreasing trend while logC and logA increase and decrease, respectively, with increase in exposure time; The test data of m and logC at each exposure time demonstrate a normal distribution, and the means of the data show a linear correlation with exposure time. The proposed linear prediction model is proved feasible in predicting fatigue resistance, including m and logC in Paris law with longer exposure time, but it does not fit in predictions based on n and logA. © 2026 Wiley-VCH GmbH.