Abstract :

Duplex Stainless Steel (DSS) Has Emerged As One Of The Most Important Engineering Materials For Offshore Structures, Shipbuilding, Marine Pipelines, Desalination Plants, Heat Exchangers, Pressure Vessels, And Coastal Infrastructure Owing To Its Excellent Combination Of High Mechanical Strength, Superior Corrosion Resistance, Good Weldability, And Outstanding Resistance To Chloride-induced Stress Corrosion Cracking. The Balanced Dual-phase Microstructure Consisting Of Approximately Equal Proportions Of Ferrite (δ) And Austenite (γ) Enables Duplex Stainless Steels To Exhibit Significantly Better Mechanical And Corrosion Properties Than Conventional Austenitic Or Ferritic Stainless Steels. However, Fusion Welding Processes Such As Gas Tungsten Arc Welding (GTAW), Gas Metal Arc Welding (GMAW), Laser Beam Welding (LBW), And Shielded Metal Arc Welding (SMAW) Often Introduce Excessive Heat Input, Resulting In Undesirable Phase Imbalance, Grain Coarsening, Residual Stresses, Chromium Nitride Precipitation, Sigma Phase Formation, And Deterioration Of Corrosion Resistance, Particularly In Aggressive Marine Environments. These Metallurgical Changes Considerably Reduce Structural Integrity And Long-term Service Performance. This Study Presents A Comprehensive Investigation Entitled Microstructural Evolution And Corrosion Behavior Of Friction Stir Welded Duplex Stainless Steel Under Marine Environmental Conditions. Duplex Stainless Steel Plates Are Joined Using Optimized Friction Stir Welding Parameters, Followed By Extensive Characterization Employing Optical Microscopy (OM), Scanning Electron Microscopy (SEM), Electron Backscatter Diffraction (EBSD), Energy Dispersive X-ray Spectroscopy (EDS), X-ray Diffraction (XRD), Microhardness Evaluation, Tensile Testing, Electrochemical Impedance Spectroscopy (EIS), Potentiodynamic Polarization, Salt Spray Exposure, And Immersion Corrosion Testing In Simulated Seawater. The Relationships Among Welding Parameters, Microstructural Refinement, Phase Evolution, Passive Film Stability, Corrosion Kinetics, And Mechanical Performance Are Systematically Analyzed. Experimental Results Demonstrate That Optimized Friction Stir Welding Produces Defect-free Joints Exhibiting Refined Duplex Microstructures, Balanced Ferrite-austenite Phase Distribution, Improved Hardness, Enhanced Corrosion Resistance, Superior Passive Film Stability, And Excellent Mechanical Integrity, Thereby Demonstrating The Suitability Of Friction Stir Welded Duplex Stainless Steel For Advanced Marine Engineering Applications.

Published:

21-4-2025

Issue:

Vol. 25 No. 4 (2025)

Page Nos:

392-407

Section:

Articles

License:

This work is licensed under a Creative Commons Attribution-NonCommercial-NoDerivatives 4.0 International License.

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