To study the laser cladding of ultra high strength AerMet-100 alloy powder on AISI-4340 steel for repair and refurbishment

Abstract

High Tensile Steels such as AISI-4340 is extensively used steel in various engineering sectors such as aerospace, defense, automotive, heavy engineering and power sectors for components such as pinion housing, gears, shafts, connecting rods, propeller shafts, & landing gears of aerospace vehicles etc. Such component faces extensive wear at the contact areas during operation resulting in loss of performance leading to replacement. Directed energy deposition or laser cladding for refurbishment of such components can reduce the cost of replacement and can also be advantageous in countering environmental concerns. In this study, feasibility of using AerMet-100 alloy powder for refurbishment of AISI4340 steel was explored using laser cladding process. A 6 kW diode laser with 6 + 2 axes robot was used for the experimentation where laser clads were generated by melting and depositing the powder that was fed through a powder-feeding nozzle. AerMet-100 clads were found to have good compatibility with the substrate and defect free clads were generated. In order to homogenize the microstructure at Heat Affected Zone, a post-clad heat treatment (PCHT) at 470 °C for 1hr was carried out. The as-cladded microstructure shows lath martensite with retain austenite, whereas post clad heat-treated sample shows slightly reduced retained austenite. Micro-hardness evaluation revealed increased in clad hardness after PCHT due to formation of fine carbides. Micro-tensile test of Post heat-treated clad showed max Tensile stress of 1752 MPa compared to substrate 1240 MPa. It can be concluded that AerMet-100 material can be a potential candidate for repair and refurbishment of AISI4340 steel.