Influence Of Ultrasonic Surface Intense Plastic Deformation On Electrochemical Behavior Of Pipeline Steel

Surface conditions have significant impact on corrosion, fatigue and friction. The wholeperformance of X80pipeline steel can be improved through perfecting the surface condition,which has great significance for long-term safty operation of pipeline.On the base of feature of ultrasonic surface rolling processing (USRP) and thecharacteristic of X80pipeline steel, X80pipeline steel was treated by USRP with twodifferent technological parameters. The surface roughometer, microhardness tester,metalloscopy and transmission electron microscopy technique were adopted to study theroughness, microhardness, plastic deformation layer and grain size of X80pipeline steeltreated by USRP, respectively. In view of residual stress induced by USRP, finite elementanalysis software ANSYS was used to analyse the distribution of residual stress. Minewhile,the electrochemical behaviors were investigated by polarization curve and electrochemicalimpedance spectroscopy technique. The results show that:USRP reduces the surface roughness, increases the microhardness and refines the surfacegrain of X80pipeline steel. The surface roughness and surface grain size decreases, andsurface microhardness and plastic deformation improve with the processing times increasing.Residual compressive stresses are introduced into the surface layer of X80pipeline steel.Maximum residual deformation and the distribution range of residual stress increase with thepress amount increasing.In nearly neutral solution and high pH value solution, USRP improves the corrosionresistance of X80pipeline steel.