Cavitation erosion resistance improvement of a Multipass Friction Stir Processed UNS S32205 Duplex Stainless Steel

Duplex stainless steel has been characterized as a well behave material under high mechanical loads and corrosive environments. However its cavitation erosion resistance could limit its application in minning, chemical, petrochemical and offshore industries.  This paper investigates the behavior of a UNS S32205 duplex stainless steel rolled and annealed that has been friction stir processed by a multipass and overlap series of beads using a PCBN/W-Re tool.

Samples were obtained after FSP and tested in a 20 kHz vibratory cavitation equipment all the surfaces were characterized using roughness measurements and SEM.Cavitation erosion resistance is improved by this process when comparing incubation times and maximum erosion rates on nugget zones and the as received material, these results are related to changes in the microstructure of steel that modify its tribological properties.

Keywords: Friction stir welding, duplex stainless steel, wear resistance.