Study Electrochemical Corrosion Of Stainless Steel And Welding Seam

Used the electrochemical workstation CHI660D, in this thesis we studied the electrochemical corrosion property of four kinds stainless steel named304、316L、2205and2507in the complexity corrosion environment which simulate the Tarim Oilfield and the electrochemical corrosion property of stainless steel304、Plasma welding seam、TIG welding seam、submerged arc welding seam in the different concentration solution H2SO4、HCl、NaOH、6%FeCl3.Comparing the corrosion products membranes after electrochemical corrosion by using the scanning electron microscope(SEM). That offers theories for precautioning and relieving the corrosion of the stainless steel、stainless steel welding seam and experimental data and guide for the using of stainless steel productions under the corrosive environment.To investigate the corrosion resistance of four kinds stainless steel named304、316L、2205and2507, in three temperature conditions (20℃、50℃and80℃), we measure their electrochemical characteristic value in the complexity corrosion environment which simulate the Tarim Oilfield using electrochemical method. Verifying the result with immersion corrosion. In addition, we study and analyze the corrosion products membranes of the four kinds of stainless steel in the above different corrosion environment with scanning electron microscope (SEM). In the two complexity corrosion environment, increasing temperature, the four kinds of stainless steel corrosion resistance and pitting resistance will reduce. Adding CO2is complex for the influence on the corrosion of stainless steel process.20℃, the four kinds of stainless steel corrosion resistance and pitting resistance will reduce with adding CO2.However,50℃and80℃, the four kinds of stainless steel corrosion resistance and pitting resistance will raise with adding CO2-The corrosion resistance of four kinds of stainless steel from strong to weak is2507、2205、316L、304in the same corrosion condition.To investigate the corrosion resistance of304stainless steel and its three different welding seam, we measure their electrochemical characteristic value in (10%,60%,80%)H2SO4,(1%,3%,10%)HC1,(10%,20%,30%)NaOH and6%Fecl3solution using electrochemical method at room temperature. Verifying the result with immersion corrosion. In addition, we study and analyze the corrosion product membranes of304stainless steel and its three different welding seam in the above different corrosion environment with scanning electron microscope (SEM). The result are as follow:In H2SO4and HC1solution, the sequence of corrosion degree of304stainless steel and its three different welding seam are60%H2SO4>10% H2SO4>80%H2SO4and10%HC1>3%HCl>1%HCl.The corrosion phenomenon of304stainless steel and its three different welding seam are not clear in NaOH solution (the roughly order is30%NaOH>20%NaOH>10%NaOH). In comparison in NaOH soultion, the corrosion phenomenon is more obvious in H2SO4, HCl and FeCl3soultion.The electrochemical corrosion resistance property of304stainless steel and its three different welding seam,from weak to strong is plasma welding、TIG welding、 submerged-arc welding、304stainless steel.