Evaluation of soil factors influencing corrosion of buried X70 pipeline steel

Soil corrosion is one of the important factors for safe operation of buried X70 pipelines. The main environmental factors of soil corrosion for X70 and Q235 steels were determined using fuzzy clustering, and the order and weight of the main factors were investigated by means of grey relationship analysis and analytical hierarchy process methods. The calculation results showed that the weihgt of factors for the soil corrosion of X70 steel decreased in the following order: pH value (0. 4050) , water content (0. 2517) , conductivity (0. 1493) , salt content (0. 0868) , Cr^- (0. 0501) , NO₃^- (0.0291), SO^2-₄ (0.0173), HCO3^- (0.0107), and the results for Q235 steel were little different from those. These results provided some new reference data for establishing an evaluation method for soil corrosion of underground pipelines.