CORROSION FAILURE ANALYSES OF INDUSTRIAL WASTE WATER HEATING PIPE

Chemical composition analysis,X-ray diffraction,optical microscopy and electrochemical testing methods were adopted to test the corrosion of steel pipe.The corrosion accumulation in the steel pipe was composed of Fe3O4,Fe2O3,Fe2(SO4)3 and FeS.The pH value of medium water in heating pipe was 7.5~8.26 and lower than the pH value 10~12,which is the value corresponding to minimum corrosion speed.Concentration of Cl- was high and that of SO2-4 was about double of the standard value.These factors could influence the corrosion speed and corrosion performance of steel pipe.The banded structure in the steel pipe had hardly influenced the corrosion.The industrial waste treatment should be carried out to improve the life time of the heating steel pipe before it is used.