Role of typical soil particle‐size distributions on the long‐term corrosion behavior of pipeline steel

Abstract

The electrochemical behavior of X70 pipeline steel in a 1.5 wt% NaCl sandy soil environment with two typical particle size distributions (PSD), continuous gradation (CG), and gap gradation (GG) was investigated using electrochemical measurements, scanning electron microscopy (SEM), and X-ray diffraction (XRD). The results showed that, as the burial time increased, the corrosion rate of X70 pipeline steel increased in the initial corrosion stage, decreased at an intermediate stage, and then increased in the final stage in these two typical soil PSD environments. However, compared with the soil PSD pertaining to the CG environment, the corrosion rate of steel increased significantly in the GG environment, as evinced by the severe corrosion spots observed on the steel surface, attributed to the fact that, in the soil PSD for the GG environment, both the extent of liquid dispersion, and the number of galvanic cells increased, accelerating the cathodic step, i.e., oxygen-reduction reaction in the three-phase boundary (TPB) zone, and anodic step, i.e., the metal dissolution stage, of the X70 pipeline steel corrosion process, respectively. Both the anodic and cathodic processes were activation controlled. Thus, the corrosion of X70 pipeline steel was considerably dependent on the soil PSD in sandy soil environments. Materials and Corrosion 2016, 67, No. 5 Role of soil PSD on the corrosion behavior of steel Figure 15. SEM micrographs of the surface morphologies of X70 pipeline steel in (a) CG PSD soil; (b) GG PSD soil www.matcorr.com

Electrochemical Corrosion Behaviour of X70 Steel under the Action of Capillary Water in Saline Soils

“…This is because the dielectric constant of the soil increases as the sodium chloride content increases [ 52 ]. In addition, the results of the study show that the polarization resistance is inversely proportional to the corrosion rate of the metal [ 53 ]. This means that the corrosion rate of X70 steel increases with the increase of sodium chloride content in soil corrosion environment.…”

Experimental study on resisted water pressure for connecting welds of polypropylene plastic plates in underground silos

“…A steel plate is effective for waterproofing and difficult to break. However, the contact between the steel plate and water easily rusts, restricting the application of steel plates as waterproof layers [6][7][8]. Plastic materials are light and corrosion resistant, with low thermal conductivity, heat preservation, waterproofing and energy saving capabilities, and convenient processing and formation [9].…”

Expecting of Corrosion Rate in a Material Affected by Differences Soil Type in Controlled Environments.

“…This research shows that the model that was developed corresponds with the prediction on the rate of corrosion development with the soil pH and the resistivity of soil, both are set as an independent variable. A few research about the underground pipe and other structure corrosion has been done (Biezma et al, 2018;Wasim et al, 2018;Wang et al, 2018;Atanov et al, 2018;Thalib et al, 2018;He et al, 2012;Velayudhan and Yameni, 2012).…”