Deposition of Inconel 718 Powder on a Steel Substrate Using the Pulsed Micro TIG Process

نوع: Type: Thesis

مقطع: Segment: masters

عنوان: Title: Deposition of Inconel 718 Powder on a Steel Substrate Using the Pulsed Micro TIG Process

ارائه دهنده: Provider: Samaneh Yosefi Yeganeh

اساتید راهنما: Supervisors: Dr.Mohsen Sheikhi _Dr.Esmaeil Damavandi

اساتید مشاور: Advisory Professors:

اساتید ممتحن یا داور: Examining professors or referees: Dr. Hassan Alamkhah Dr. Meysam Nouri

زمان و تاریخ ارائه: Time and date of presentation: 2026

مکان ارائه: Place of presentation: سالن کنفرانس

چکیده: Abstract: In this study, the bonding behavior obtained by applying an Inconel 718 powder-containing coating onto low-carbon steel using the pulsed Micro TIG process was investigated. The effects of coating thickness and process parameters on the melt pool geometry, dilution, formation and severity of solidification cracking, solidification path, and microhardness of the joint were evaluated. For this purpose, Inconel 718 coatings with thicknesses of 0.05, 0.10, and 0.15 mm were applied, and welding was performed at power levels of 6, 8, and 10 and pulse durations of 21 and 30 ms. Microstructural and crack investigations were conducted using microscopic examinations and image analysis techniques, while the solidification behavior and crack susceptibility were evaluated using the Kou, Sheikhi, and RDG criteria. In addition, the Vickers microhardness distribution across different regions of the joint was determined. The results showed that coating thickness and process parameters had a significant effect on the melt pool geometry and dilution. Increasing the coating thickness was accompanied by a reduction in dilution under many of the investigated conditions, and the decrease in dilution generally resulted in a reduction in the number and length of cracks. The greatest reduction in crack number was observed when the coating thickness increased from 0.05 to 0.10 mm. An increase in pulse duration from 21 to 30 ms also resulted in a decrease in the average number of cracks under the investigated conditions. The relationship between dilution and crack susceptibility was nonlinear; however, cracks were rarely observed at dilution levels below approximately 0.65, whereas the tendency for crack formation increased as dilution reached approximately 0.80 and higher. The investigation of the solidification path also showed that variations in dilution altered the chemical composition and solidification conditions of the mixed weld metal. Comparison of the crack prediction criteria indicated a critical dilution level of 0.81 in the final assessment. The microhardness results showed the highest hardness at the center of the fusion zone, followed by a gradual decrease toward the heat-affected zone and base metal. Overall, the results demonstrated that the simultaneous control of coating thickness and process parameters played an important role in controlling dilution, reducing solidification crack susceptibility, and achieving a joint with suitable properties.