Microstructure, Mechanical Properties, and Corrosion Resistance of ER2209 Duplex Stainless Steel Manufactured by Plasma Arc Welding

The thin-walled part of ER2209 duplex stainless steel was prepared by plasma arc welding on the surface of Q235 substrate. The microstructure, mechanical properties, and corrosion resistance of the thin-walled part in different layers were investigated. The results show that the microstructure consisted of ferrite and various morphologies of austenite, including grain boundary austenite, Widmanstätten austenite, and partially transformed austenite. The austenite content gradually increased from 42% in the 05th layer to 58.5% in the 30th layer. The microhardness decreased from 293 HV in the 05th layer to 248 HV in the 30th layer and ultimate tensile strength decreased from 887 MPa in the 05th layer to 720 MPa in the 30th layer, while the elongation increased from 32.9% in the 05th layer to 40.7% in the 30th layer. The tensile samples in different layers showed ductile fracture. The corrosion resistance was enhanced with an increasing number of layers.