Corrosion Behavior Of 2507 Super Duplex Stainless Steel In Marine Environment

The 2507 super duplex stainless steel is often used to make stainless steel pipes in umbilical cables because of its superior corrosion resistance.Umbilical cords are often used in deep-sea environments to transmit electrical signals and chemical reagents between various offshore platforms.In practice,the umbilical cord is subjected to harsh environmental corrosion conditions,including pressure,temperature,salt content,dissolved oxygen,pH value,sea water velocity and Marine life.In addition,electromagnetic field will be generated in the process of transportation power,and the existence of electromagnetic field will also affect the corrosion of materials.Although 2507 super duplex stainless steel corrosion resistance is very good,but under the coupling of various corrosion environment,will still be serious effects on the corrosion of steel tube,this will affect the normal work of umbilical cord cable,even may cause serious economic losses,so the deep sea environment corrosion of different factors on the 2507 super duplex stainless steel is necessaryIn this paper,the electrochemical detection and SEM and EDS testing methods such as open circuit potential,dynamic potential polarization,constant potential polarization,electrochemical impedance spectrum,Mott-Schottky analysis and SEM and EDS test methods are used,first of all,the effects of different electromagnetic field strength sizes on 2507 super-bipolar stainless steel corrosion,and through the fitting analysis of electrochemical data,the mechanism of the effect of electromagnetic field intensity on its corrosion.Using PDM to optimize the corrosion data of 2507 super-bipolar stainless steel at different pH,the passive membrane growth dynamics parameters of the material in the pH6.5-8.5 boric acid-sodium boric acid buffer solution were obtained.In this paper,the effect of hydrostatic pressure on the friction allot wear performance of 2507 super-dual stainless steel is studied by CLSM,and the friction wear mechanism is summarized,and the friction wear mechanism is explained to some extentThe results of this paper show that the presence of electromagnetic field will affect the corrosion behavior of 2507 super-bipolar stainless steel in artificial seawater,under five different electromagnetic field strength conditions,2507 super-dual stainless steel in 3.5wt%NaCl solution in the anode polarization region directly passivation,can form a more stable blunt membrane structure The content of Cr element in the 2507 super-dual stainless-steel passivation film decreases,while reducing the protective action and repair capacity of the passivated membraneThe results of the optimal fitting of 2507 super-dual stainless steel passivation at different pH values using PDM show that under pH6.5,7.5,8.5,2507 super-bipolar stainless steel can form a more stable passivation film,but under pH 6.5,the 2507 double-phase stainless steel without voltage is more prone to corrosion,but after entering the passivation zone,Under this condition,it is more likely to form the passivation film.2507 super-bipolar stainless steel in the passivation zone formed by the passivation film is mainly n-type passivation film,and as the pH is worth increasing,the donor density is getting larger,so,relative to pH7.5 and pH8.Under 5 conditions,pH6.5 at 2507 super-dual-phase stainless steel surface passivation film has more protective performance,and 2507 super two-phase stainless steel in steady state conditions,steady current density is independent of the applied voltage,and with the increase of voltage and pH,The thickness of the passivation film is getting bigger and biggerHydrostatic pressure will affect the frictional wear performance of 2507 super-bipolar stainless steel,friction under normal pressure basically satisfies the three-body friction theory,but with the increase of static water pressure,friction coefficient and wear rate become larger,friction wear becomes more serious,.2507 super-bipolar stainless steel wear behavior under high hydrostatic pressure and layered wear corrosion mechanism,the main grinding particles are in line with the grinding particles.