| Stainless steel is widely used in chemical, medical and textile industry because of itsgreat workability, usability and corrosion resistant properties. Effusion slot parts of thescouring machine in the field of textile industry are generally composed of stainless steelmaterials. These materials are served in the strong corrosion resistance medium of strong acid,alkali solution and under the condition of hot temperature. Therefore, it is necessary to studythe corrosion resistance of effusion slot parts of the scouring machine.Effusion slot parts of the scouring machine are made of904L,316L austenitic stainlesssteel and2507duplex stainless steel. Acid washing zone of effusion slot parts is made of904Laustenitic stainless steel, which corrosive medium is5g/L H2SO4solution; desulfurizationzone of effusion slot parts is made of316L austenitic stainless steel, which corrosive mediumis4g/L NaOH solution, bleaching region of effusion slot parts is made of2507duplexstainless steel, which corrosive medium is5g/LNaClO solution.The corrosion resistant properties of effusion slot parts of the scouring machine scouringmachine were studied in the paper. These were made of the above three kinds of stainless steel.First of all, the intergranular corrosion behavior of the base metal and welded joint ofthree kinds of stainless steel were investigated by using the electrochemical potentiodynamicreactivation (EPR), the results of the EPR showed that the reactivation rate(Ra) of three kindsof stainless steel were less than1%, which indicated the good intergranular corrosionresistance of them.Secondly, the electrochemical corrosion properties of the base metal and welded joint ofthree kinds of stainless steel was investigated by using potentiodynamic polarization curve andelectrochemical impedance spectroscopy. The results showed that the excellent corrosionresistance of the base metal and welded joint of904L austenitic stainless steel in5g/L H2SO4solution at25℃and90℃,316L austenitic stainless steel in4g/L NaOH solution at25℃and80℃,2507duplex stainless steel in5g/L NaClO solution at25℃and60℃. Meanwhile, thecomposition of the passive film formed on the corrosive surface of the904L austeniticstainless steel in5g/L H2SO4solution,316L austenitic stainless steel in4g/L NaOH solutionand2507duplex stainless steel in5g/L NaClO solution were studied by using the X-ray Photoelectron Spectrometer (XPS) analysis. The research results showed that the passivationfilm of904L austenitic stainless steel and2507duplex stainless were mainly composed ofoxide of Cr,316L austenitic stainless steel was mainly composed of oxide of Fe and Cr.Therefore, they exhibited excellent corrosion resistance.Finally, the high temperature oxidation performance of three kinds of stainless steel werestudied. Isothermal oxidation kinetic curves of904L,316L austenitic stainless steel and2507duplex stainless steel were determined by Ma Fu-lu heating equipment at900℃for100h. Theresults showed that the oxidation rules of three kinds of stainless steel were to according withthe parabolic law. The results of scanning electron microscope and X-ray diffraction (XRD)analysis showed that904L austenitic stainless steel and the2507duplex stainless steel surfacecan form the complete oxide film of rich chromium at900℃for100h, which indicated goodoxidation resistance. The partial oxidation film of corners of316L austenitic stainless steelwere tripped at900℃for100h, which indicated a bit poor oxidation resistance. |
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