Repair Welding of Corroded Soft-Martensitic Duplex Stainless Steel GX4CrNi13-4

Duplex stainless steels are grades with typically almost equal parts of two phases at room temperature. These two phases could be austenite-ferrite or ferrite-martensite or even austenite-martensite. Some types of these alloys provide good performance characteristics but had limitations in the as welded condition. In this paper, welding parameters with GTAW had been tested for repair welding of a corroded ascast part of ferritic-martensitic stainless steel called soft-martensitic which is suffered from erosion corrosion and pitting corrosion. Results showed that the corrosion resistance and mechanical properties of weld metal and HAZ are significantly much better than the base metal. But increasing the heat input causes to lower ductility and impact energy. It is important to note that this document is a report for repair welding of a very common steel in dams and power plants so the metallographic observation test didn’t performed because the results are coincident on previous studies. In the other word the most important goals of this work are achieving to higher corrosion resistance, higher thickness of weld, lower distortion andbetter mechanical properties

Keywords:

ferritic-martensitic Duplex Stainless Steel , Repair Welding , Corrosion Resistance , GTAW