Comparison of the Mechanical Properties of Hastelloy X Material after Welding by GTAW and Nd-YAG Laser

Abstract

Cracks induced by metal fatigue and structural aging effect can’t be fixed by traditional Gas Tungsten Arc Welding (GTAW), consequently cause the increasing of defect ratio. Although some cracks might be acceptable and qualified to field service standard subject to the military regulation, however, in certain areas, e.g. brazing and coating areas, the results are not ideal especially the HAZ and residual stress. In this study, Nd-YAG Laser welding and traditional GTAW processes were performed on Hastelloy X superalloy for comparison. Post-welding residual stress distribution was measured by X-ray diffraction method. Macro- and microstructure were observed by metallurgical OM and SEM in comparison to the hardness testing. Tensile test results show that traditional welding technology has better ultimate tensile strength and ductility. For the Nd:YAG laser welding, residual stress is limited to 3mm of the both sides of weld and drops drastically, while higher amplitude and widely spread in the GTAW welding. It is proposed that combining both methods, the repairing process can be optimized to reduce the defect ratio and save repairing time.

Microstructure and Properties of a Repair Weld in a Nickel Based Superalloy Gas Turbine Component

“…The important properties are also: excellent formability, high mechanical properties at elevated temperatures, and resistance to oxidation and stress corrosion. Additional chemical elements are chosen to ensure the aforementioned properties, as well as providing resistance to creep and brittle fracture [5,6]. According to Zhao [7], in addition to primary phases γ and M 6 C, topologically closed packed phases and M 23 C 6 can also precipitate in the aged material.…”

Laser controlled melting of Hastelloy X alloy with presence of B4C particles at surface

“…The influence of laser pulse parameters on the processing of Hastelloy X alloy was investigated by Bright et al 2 They established a relationship between the laser pulse parameters and the material removal rate as well as the amount of residual resolidified material at the surface. The mechanical properties of laser welded Hastelloy X alloy were studied by Wu et al 3 They showed that laser processing improved the mechanical properties of the resulting weld sites. Laser treatment of Hastelloy X alloy surface was examined by Wang 4.…”