Cavitation Erosion Behavior of Nb Strengthened Duplex Stainless Steel Surfacing Layer

In this paper, the Nb-containing duplex stainless steel (DSS) was prepared using the tungsten inert-gas welding powder surfacing method, and the solution treatment was carried out at different temperatures. A scanning electron microscope with an energy-dispersive spectrometer, universal testing machine, and ultrasonic cavitation equipment were used to study the structure, mechanical properties, and cavitation erosion (CE) resistance of DSS. The results showed that, compared with the as-welded 2209 DSS, Nb-containing DSS has better strength and lower plasticity. After heat treatment, the strength and plasticity of Nb-containing DSS were also reduced. During the ultrasonic CE test, the cumulative weight losses of the Nb-containing DSSs for 6 h were less than that of the control group (2209 DSS). However, solution treatment caused the Z phase to appear in the Nb-containing DSSs. Z phase reduced the mechanical properties of the matrix, promoted the initiation of CE cracks, and increased the cavitation weight loss of the sample after heat treatment.