Surface Treatment and Corrosion
Improvement of Corrosion Resistance of Simulated Weld Heat Affected Zone in High Strength Pipeline Steel Using Electropulsing
2020 Volume 60 Issue 9 Pages 2015-2023
Details
2020 Volume 60 Issue 9 Pages 2015-2023
Subjected to quenching processing, the samples of weld heat affected zone containing microstructures of martensite in high strength pipeline steel were simulated and prepared. Effects of electropulsing treatment on the corrosion resistance of simulated samples were studied through electrochemical detections and immersion corrosion experiments. It was found that the corrosion resistance of pipeline steel decreased sharply due to the high lattice strains/dislocation densities and residual tensile stress developed after martensite transformation by water quenching. Interestingly, treated by electropulsing the corrosion resistance of simulated weld heat affected zone samples was dramatically improved, and even exceeded that of the base metal when the current density achieved 5.2 kA/mm2. After electropulsing treatment, the dislocation density and residual stress of the investigated samples were reduced largely, and the rust layer generated after corrosion was more compact, so that its corrosion resistance was improved.
