Study On The Effect Of SRB On The Carbon Steel's Corrosion

In order to research the pipeline inner corrosion and outer corrosion of carbon steel.It use the means of metallographic microscope observation method, electrochemical impedance method and polarization curve method,to study the sulfate reducing bacteria(SRB) of X70 pipeline steel, 20 # pipeline steel, L245 pipeline steel in oil-water system and the effect of corrosion behavior in the soil simulation solution,Metallographic experiment results show that when SRB exists in oil-water system,with the increase of soaked days of SRB, X70 steel lost the luster of the metal surface, and some material attached on the surface of the sample surface became rough, and there is pitting corrosion pit. The more days, pitting corrosion pit are interconnected to pitting phenomenon is more serious. Under the same temperature, the lower concentration of SRB on corrosion of carbon steel slow down, corrosion degree decreases with the concentration of reducing. Of SRB on corrosion of carbon steel with temperature, the slow, corrosion degree decreases as the temperature reduction.Electrochemical experiment results show that under the condition of the same external environment, in the oil-water system, SRB can accelerate the three kinds of material of steel corrosion, increase its corrosion tendencies. Early immersion, the SRB effect on three kinds of steel corrosion is the largest and most; As the soaking time, the corrosion reaction is still on, only to slow down the corrosion rate. SRB to exist three kinds of steel plate process, promote the cathodic depolarization effect, accelerated the cathodic reaction.Biofilm is contributed to the 20 # steel corrosion.the factors as concentration and temperature of SRB affect the SRB corrosion of carbon steel. At the same temperature, the concentration of SRB decreased gradually SRB for carbon steel corrosion rate decreases, the corrosion degree decreases. The SRB concentration under the same conditions, different temperature, by far the most corrosion when 30? explain the most suitable for the growth of SRB.In simulated soil solution, when increasing the concentration of C1-, the corrosion rate of X70 steel decrease at first,and then increase. when the increase of concentration of S,the speed of X70 pipeline steel at first increase and then decrease.