Comparison of laser clads and overlays made with the plasma transferred arc process

Abstract

The comparative effects of the plasma transferred arc process (PTA) versus laser cladding on ASTM A-105 were investigated and compared. PTA-produced overlays were prepared by Plasma Specialties Worldwide Inc. using state-of-the-art commercial PTA equipment and parameters. Laser clad specimens were prepared at the Applied Research Laboratory, Pennsylvania State University (ARL Penn State) using a 14 kW CO2 laser and a 3 kW Nd: YAG laser. Inconel 625™ wire was used with the Nd: YAG laser; Inconel 625™ powder was used on two of the clad specimens with the CO2 laser (high iron and low iron content); the same low iron content Inconel 625™ powder was used with the plasma clad specimen; and finally, a relatively new Ultimet™ (Chrome-Cobalt) powder was used on another CO2 clad specimen. The effects induced by the chemistry and the deposition process on microstructure, micro hardness, chemistry, iron dilution, and wear performance were analyzed.The plasma clad specimen exhibited the largest grain size, highest iron dilution, and lowest wear resistance. The CO2 and YAG laser clad specimens had smaller grain size, lower iron dilution, and superior wear resistance. Among the laser clads, the specimen clad with the Nd: YAG laser provided the best performance in wear tests. The YAG specimen had the lowest iron dilution, smallest grain structure, and high micro hardness near the surface of the clad, all of which may be responsible for the superior wear performance exhibited by this specimen.The comparative effects of the plasma transferred arc process (PTA) versus laser cladding on ASTM A-105 were investigated and compared. PTA-produced overlays were prepared by Plasma Specialties Worldwide Inc. using state-of-the-art commercial PTA equipment and parameters. Laser clad specimens were prepared at the Applied Research Laboratory, Pennsylvania State University (ARL Penn State) using a 14 kW CO2 laser and a 3 kW Nd: YAG laser. Inconel 625™ wire was used with the Nd: YAG laser; Inconel 625™ powder was used on two of the clad specimens with the CO2 laser (high iron and low iron content); the same low iron content Inconel 625™ powder was used with the plasma clad specimen; and finally, a relatively new Ultimet™ (Chrome-Cobalt) powder was used on another CO2 clad specimen. The effects induced by the chemistry and the deposition process on microstructure, micro hardness, chemistry, iron dilution, and wear performance were analyzed.The plasma clad specimen exhibited the largest grain size, highest iro...