Interactive influence of environmental factors on the pitting susceptibility of X120 pipeline steel studied by a uniform design method

A uniform design experimental method was employed to discuss the interactive influence of Cl^- concentration, pH values and temperature on the pitting susceptibility of X120 pipeline steel in HCO₃^- + Cl^- solutions by a potentiodynamic scan technique. The experimental results indicate that Cl^- concentration, pH values and temperature have great effect on the corrosion and passive behavior of X120 pipeline steel in HCO₃^-+ Cl^- solutions, and the influence order is as follows: Cl^- concentration has the greatest impact, then the combined action of Cl^- concentration and temperature, the third one is pH values, and temperature has the smallest impact. X120 pipeline steel has the least pitting susceptibility in the HCO₃^- + Cl^- solution whose Cl^- concentration is 0 mol · L^-1, pH value is 8.5 and temperature is 0°C.