Electrochemical Corrosion Behavior Of High Strength Ship Hull Steel EH47 In Wear Condition

With the development of marine economy,a large number of marine ports and bridges had been built,and ships had been frequently used,so that more steel were used in marine development.In the marine corrosive environment,ships,marine equipment and key friction pairs that had been long-term service for would be corroded and worn by seawater and sea sand.In this paper,the wear,corrosion and electrochemical corrosion behavior of high strength ship hull steel EH47 in seawater environment were studied by means of universal friction and wear testing machine and electrochemical workstation.The 3D profile,friction coefficient,wear surface and micro-morphology of corrosion products of the worn surface of the sample were measured by 3D digital microscope,SEM and EDS and XRD.The main conclusions as follows:?1?In the laboratory universal friction and wear test,in the same rotating speed,the coefficient of friction between EH47 disk sample and grinding ball increased with the increase of load.In the condition of sand,the value of coefficient of friction was larger and the rising trend was more obvious.In without sand load of 50 N,the coefficient of friction value was the minimum.In the same load,the coefficient of friction value decreased with the increase of speed,and reached the minimum at 400 rpm.With the increase of load and rotation speed,the wear surface of EH47 steel disk sample along the sliding direction deeper,and the wear area and wear mark depth of Si3N4 grinding ball were increased.With the increase of load and rotational speed,the wear surface was relatively smooth and the furrow was reduced.?2?In the laboratory full immersion seawater test,with the extension of full immersion time,the corrosion products on the worn surface of EH47 steel increased,relatively dense,and there was without obvious microcrack,mainly showing the aggregation of needle cluster structure.By XRD analysis,the corrosion products of EH47 steel were mainly composed of Fe OOH and Fe3O4 and Fe2O3 phases.?3?The results of electrochemical corrosion test showed that the open circuit potential of the raw steel EH47 without wear decreased first and then increased with the prolongation of the full immersion time,and the lowest value was 28 days after the full immersion in seawater.The corrosion current density(I_corr)of EH47 steel first decreased and then increased with the prolongation of full immersion time,and it was the smallest in about 28 days.?4?In the electrochemical corrosion experiment,the anodic curves of EH47 steel wear surface in different wear conditions had certain passivation characteristics,and thepassivation characteristics of EH47 wear surface after 14 days and 49 days of seawater immersion were not as obvious as 0 days,and the range of passivation area was slightly narrowed.The Nyquist plots of the impedance spectrum were all an obvious capacitance arc,which was not obvious in 14 days compared with 0 days,but the impedance spectrum was irregular in 49 days.The low-frequency mode values of 14 days and 49 days after full immersion showed a decreasing trend compared with 0 days,and the impedance values were far less than 0 days,but the impedance values of 49 days showed an increasing trend compared with 14 days.?5?In the electrochemical corrosion experiment,when EH47 samples were immersed in seawater for 0 days in different wear conditions,I_corr reached its minimum,arc radius of capacitance and impedance was the largest,impedance rose up to maximum,as a result,corrosion rate was the smallest,and corrosion resistance was better.After immersion in seawater for 49 days,the wear surface of EH47 steel sample also reached the minimum when the load was 200 N and the rotating speed was 400 rpm.At 200 N and 100 rpm,I_corr was the smallest,low frequency modulus and impedance reached maximum.