Microstructural and mechanical properties of Inconel 718 TIG weldments

Venukumar, S.; Sarkar, Prasenjit; Sashank, J. Sai; Sampath, Prakrathi; Saikiran, K. Ch. S.

doi:10.1016/j.matpr.2017.11.544

Cited by 20 publications

(6 citation statements)

References 11 publications

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“…Most of the studies on TIG welding of Inconel 718 are mainly about joining sheets thicker than 1 mm. It is observed that current values have been generally preferred up to 150 A and DCEN was decided as the current type [3,12,25,26]. In our study, current values lower than 30 A resulted in metal accumulation on weld seam and distortion existed on sheets due to excess heat.…”

Section: Macro Observationmentioning

confidence: 69%

The Effect of TIG Welding Parameters and Automatization for Non-Heat Treated Inconel 718 Sheets

2021

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Inconel 718 alloy is widely used in applications that require advanced strength properties especially at high temperature conditions. Combust room walls, exhaust parts, jet tribune blades and gas tribune equipment are the most known using areas. This alloy can be welded with various fusion welding methods, but TIG (Tungsten Inert Gas) welding is preferred since, it provides simply application, mobility and low cost. This study was aimed to clarify that how adjusting the welding parameters and welding automatically can help to achieve promising mechanical properties before heat treatments. The welding experiments were conducted on three different welding current values and attention was paid to provide full penetration for each condition. The results showed that the highest welding current value which did not cause welding defects lead to decrease heat input due to the high transverse speed usage. Moreover, by automatically welding, the heat input was decreased to a minimum level that provided excellent tensile strength and elongation properties. Dendrites turned to cellular from colon. Hazardous zones, such as HAZ and PMZ, narrowed down. The Laves phase ratio and grain size also decreased. Microhardness results confirmed these microstructure observations. The crack observations after tensile tests showed that failures were near HAZ in high-heat input conditions. However, failures were observed in FZ for low-heat input conditions. Additionally, ductile fracture and fracture similar to cleavage mechanisms were observed together due to adjusting the parameters and automatization.

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Section: Macro Observationmentioning

confidence: 69%

The Effect of TIG Welding Parameters and Automatization for Non-Heat Treated Inconel 718 Sheets

2021

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“…The content of Nb and Ti supplemented and Ni, Fe and Cr decreased at point C 2 (micro-segregation region) comparing with the point C 1 (γ matrix), which confirmed the composition of the Laves phase. This indicates that Nb had redistributed into inter-dendritic regions during solidification; the content of Nb in the liquid metal reached a specific component ratio and produced an Nb-enriched phase [2]. Figure 7(d) shows the typical γ+Laves eutectic, which is distributed along the grain boundaries in a chain.…”

Section: Microstructuresmentioning

confidence: 98%

“…Due to its favourable characteristics, Inconel 718 is also an essential high-temperature structural material required for nuclear reactors, combustion chambers and chemical equipment. These include hot corrosion resistance, oxidation resistance and an excellent strength in high-temperature environments [2][3][4][5]. However, owing to the high cost of parts made of Inconel 718 superalloy, the joining of Inconel 718 with other metal materials is essential.…”

Section: Introductionmentioning

confidence: 99%

Microstructures and mechanical properties of Ni/Fe dissimilar butt joint welded using the cold metal transfer

Tang

Ding

et al. 2020

Mater. Res. Express

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In this study, dissimilar butt joints were formed between as-rolled Inconel 718 and SUS 316 using cold metal transfer (CMT) with ERNiFeCr-2 filler metal at a welding speed of 5 mm s −1 and three different welding currents (130, 160 and 190 A). The morphology, microstructure, and mechanical properties of the joints and the mechanism by which the joint interface formed were studied. The results indicate that CMT welding parameters have an effect on the weld appearance and that the weld metal exhibits better wettability and spreadability at a welding current of 160 A. The interface between the weld metal and SUS 316 base metal was characterized by applying an optical microscopy (OM) and scanning electron microscopy (SEM) equipped with energy-dispersive X-ray spectrometry (EDS). The results revealed that no obvious diffusion of Ni and Fe ions was identified across the joint interface. The fractures that initiated in the joints during the tension testing formed in the heat-affected zone (HAZ) of the SUS 316 base metal, and the high-temperature tensile strength of the joint was observed to be 424 MPa, which is approximately 87.06% of that of SUS 316 base metal (487 MPa) and 67.19% of that of Inconel 718 base metal (631 MPa). In terms of the elongation, the joint (21.9%), Inconel 718 base metal (21.2%) and SUS 316 base metal (22.3%) elongations were similar. For comparison, the joint also was tested at room temperature, resulting in a tensile strength and elongation of 511 MPa and 27.5%, respectively. A spherical elemental Ni segregation morphology was clearly observed at the high-temperature fracture. Hardness studies demonstrated that the weld metal hardness is higher than that of the SUS 316 base metal.

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“…Owing to the increase of weld cooling rate, the dendrite spacing and the size of the Laves phase were further reduced, but the operation of this method is complex and difficult to be popularized in a large scale. Therefore, the pulse current was adopted as the welding current of CCTIG to study its effect on weld microstructure and properties [27][28][29][30]. Manikandan et al [28] used the composite pulse current technology and helium shielding gas to control the formation of harmful Laves in the fusion zone during Inconel 718 welding.…”

Section: Introductionmentioning

confidence: 99%

Comparative study on CCTIG welding and PCTIG welding of GH4169 under the same heat input

Yong-jun

Zhang

Guo

et al. 2022

Materials Science and Technology

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GH4169 is a nickel-based superalloy, but high welding heat input and the harmful precipitates of the Laves phase seriously affect the mechanical properties of the welding joint. In this study, constant current tungsten inert gas welding (CCTIG) and pulsed current tungsten inert gas welding (PCTIG) were used to weld the GH4169 alloy sheet under the same heat input. After welding, the relationship between microstructure and comprehensive mechanical properties was analyzed. According to the results, under the same heat input: (1) The PCTIG welded joint has narrower weld and denser microstructure. (2) The pulse current improved the segregation of Nb element at the weld, and then reduced the precipitation of the Laves phase. (3) Pulse current improved the comprehensive mechanical properties of weld metal. The tensile strength and elongation were increased by 18% and 79% respectively.

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Microstructural and mechanical properties of Inconel 718 TIG weldments

Cited by 20 publications

References 11 publications

The Effect of TIG Welding Parameters and Automatization for Non-Heat Treated Inconel 718 Sheets

The Effect of TIG Welding Parameters and Automatization for Non-Heat Treated Inconel 718 Sheets

Microstructures and mechanical properties of Ni/Fe dissimilar butt joint welded using the cold metal transfer

Comparative study on CCTIG welding and PCTIG welding of GH4169 under the same heat input

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