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

Rakoczy, Łukasz; Grudzień, M.; Tuz, Lechosław; Pańcikiewicz, Krzysztof; Zielińska‐Lipiec, A.

doi:10.1515/adms-2017-0011

Cited by 23 publications

(14 citation statements)

References 9 publications

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“…19,No. 2 (60), June 2019 in structural steels [2] and in advanced micro-alloyed steels and alloys for high-temperature and high-pressure applications [3,4].…”

Section: Introductionmentioning

confidence: 99%

Problems of Pad Welding Structural Steels with Martensitic Filler Metal

Tasak

Ziewiec

Zielińska‐Lipiec

et al. 2019

Advances in Materials Science

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There is a problem in obtaining a suitable impact strength of the padding weld after cladding with a martensitic filler metal. Too low annealing temperature below 580°C and the excessive annealing temperature above 650°C do not provide adequate impact strength of the padding weld. A heat treatment technology for mixed joints has been developed based on the results of the microscopic observations, X-ray diffraction measurements and transmission electron microscope examination. The problem was identified and a special technology of heat treatment for the dissimilar joint was elaborated. This technology provides a high impact resistance of the padding weld and an appropriate properties of the base material.

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“…19,No. 2 (60), June 2019 in structural steels [2] and in advanced micro-alloyed steels and alloys for high-temperature and high-pressure applications [3,4].…”

Section: Introductionmentioning

confidence: 99%

Problems of Pad Welding Structural Steels with Martensitic Filler Metal

Tasak

Ziewiec

Zielińska‐Lipiec

et al. 2019

Advances in Materials Science

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“…A similar observation was also reported on Alloy X by another investigator. 38 Sihotang et al 39 reported that the P precipitate is observed around the M 6 C phases. The absence of microsegregation in the GTA and PCGTA Figure 8.…”

Section: Sem/eds Observationmentioning

confidence: 99%

Influence of pulsed current arc welding to preclude the topological phases in the aerospace grade Alloy X

Munusamy

Manikandan

2020

Proceedings of the Institution of Mechanical Engineers, Part L:

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Alloy X is prone to liquation and solidification cracks in the weldments, because of the development of topologically close-packed precipitates such as σ, P, M6C, and M23C6 carbides during arc welding methods. The present work examines the possibility of alleviating the segregation of Cr and Mo content to eliminate the development of topologically close-packed phases using a conventional arc welding technique. The welding of Alloy X has been achieved with ERNiCrMo-2 filler material by gas tungsten arc welding and pulsed current gas tungsten arc welding technique. The optical microscope shows the refined microstructure in pulsed current gas tungsten arc with respect to gas tungsten arc welding. The Mo-rich segregation was identified in gas tungsten arc weldment, and the same was absent in pulsed current gas tungsten arc. These segregations of Mo-rich content encourage the development of M3C and M6C secondary precipitates in gas tungsten arc welding. Pulsed current gas tungsten arc welding shows the existence of NiCrCoMo precipitate. The present work confirmed the absence of P, σ, and M23C6 in both the weldments of Alloy X. The ultimate tensile strength, microhardness, and impact strength of pulsed current gas tungsten arc welding are increased by 3.39, 9.17, and 21.62%, respectively, with gas tungsten arc welding. The observed Mo-rich M3C and M6C secondary phases in the gas tungsten arc welding affect the tensile strength of the weldments.

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“…The factor that can successfully mitigate the effects of such crises is the continuous improvement of power unit efficiency. This has prompted the power sector to increase the pressure and temperature of their steam boilers to reduce CO 2 , NO x , and SO x emissions [1][2][3][4]. Due to environmental restrictions having increased in recent years, new advanced ultra-supercritical (A-USC) plants ensure presently higher efficiencies compared to conventional fossil-burning power investigate the influence of the various Al/Ti ratios and tantalum addition on the primary microstructure, microsegregation of alloying elements, phase transformation temperatures, coefficient of thermal expansion and Vickers hardness.…”

Section: Introductionmentioning

confidence: 99%

Fabrication and Characterization of the Newly Developed Superalloys Based on Inconel 740

et al. 2020

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The chemical composition of standard Inconel 740 superalloy was modified by changes in the Al/Ti ratio (0.7, 1.5, 3.4) and addition of Ta (2.0, 3.0, 4.0%). Remelted Inconel 740 (A0) and nine variants with various chemical compositions were fabricated by lost-wax casting. The microstructure, microsegregation, phase transformation temperatures, thermal expansion coefficients and hardness of the superalloys were investigated by scanning electron microscopy, energy dispersive X-ray spectroscopy, differential scanning calorimetry, dilatometry and Vickers measurements. Typical dendritic microstructure was revealed with microsegregation of the alloying elements. Segregation coefficient ki for Ti, Nb and Ta did not exceed unity, and so precipitates enriched mainly in these elements were found in interdendritic spaces. The Nb-rich blocky precipitates, MC carbides, MN nitrides, oxides, and fine γ’ was in all modified castings. Presence of other microstructural features, such as Ti-rich needles, eutectic γ-γ’ islands, small Al-rich and Cr-rich precipitates depended on the casting composition. The lowest solidus and liquidus temperatures were observed in superalloys with a high Al/Ti ratio. Consequently, in A7–A9 variants, the solidification range did not exceed 100 °C. In the A0 variant the difference between liquidus and solidus temperature was 138 °C. Hardness of all modified superalloys was at least 50% higher than for the remelted Inconel 740 (209 HV10).

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

Cited by 23 publications

References 9 publications

Problems of Pad Welding Structural Steels with Martensitic Filler Metal

Problems of Pad Welding Structural Steels with Martensitic Filler Metal

Influence of pulsed current arc welding to preclude the topological phases in the aerospace grade Alloy X

Fabrication and Characterization of the Newly Developed Superalloys Based on Inconel 740

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