Experiment of Soil External Corrosion Characteristics for Stainless Steel Pipeline Materials of Water Supply
The chloride ion(Cl-)and moisture ofthe latosol were selected to investigatethe external corrosion behaviors of three types of stainless steel,304,304L,316L.The results revealed that 316L stainless steel exhibited strong resistance of environmental erosion,304L followed and 304 the worst in latosol no matter in the concentrations of Cl-and moisture.Particularly,when experimental latosol contained Cl-from 10 mg/kg to 1 250 mg/kg,the increments of corrosion current(ΔIcorr低)of the three types of stainless steel appeared obviously,where 304L>316L>304.When the concentration of Cl-varied from 1 250 mg/kg to 2 500 mg/kg,the relative lower increments of ΔIcorr高 were obtained,where 304L>304>316L,indicating that the soil environment with low Cl-promoted corrosion and high Cl-suppressed corrosion.Additionally,when the moisture of latosol was changed from 5%to 35%,the ΔIcorr values of three type stainless steel ordered by 304L>316L>304.When the moisture of soil increases from 15%to 25%,Icorr varied more obviously,and 304L>316L>304,indicating that moisture was conducive to improve corrosion progresses of the buried stainless steel under a certain range.
water supply pipelinestainless steelsoil external corrosionpotentiodynamic polarization curveelectrochemical impedance spectroscopy