Abstract
This work sets out a development of the equipment and an evaluation of the process of powder fed transferred arc plasma welding (PTA powder) with an emphasis on its utilization in coating metallic surfaces out of a flat position. After analysing the possibility of using the process in refurbishing hydraulic turbines eroded by cavitation, an analysis was made of the performance of the process and of the influence of the type of current (constant direct current and pulsed direct current) on resistance to cavitation of Stellite 6 alloy in accordance with ASTM standard G-32/92, by the indirect method. From the Stellite 6 alloy coatings deposited by the PTA process – powder using constant direct current and pulsed direct current, no significant difference was observed in the resistance to cavitation. On the other hand, the resistance to cavitation of the Stellite 6 alloy coatings obtained by the PTA powder process showed a performance higher than that of the Cavitec alloy obtained with the MIG and wire fed PTA welding processes.
Acknowledgements
The authors would like to thank Cleide Márquez and Bruno Ventura for carrying out the cavitation tests.
Notes
Article based on a version presented at the XXXI CONSOLDA, São Paulo, Nov 29–Dec 1 2005.