Review of Weldability of Precipitation Hardening Ni- and Fe-Ni-Based Superalloys

Andersson, Joel

doi:10.1007/978-3-319-89480-5_60

Cited by 8 publications

(5 citation statements)

References 40 publications

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“…Based on past discussions, these liquation cracks can be attributed to constitutional liquation, which induced shrinkage stress under solidification in the absence of additional liquid flow during cooling. The occurrence of constitutional liquation and the corresponding liquation cracking observed here has also been demonstrated previously for Ni-based superalloys under large temperature and compositional gradients when the shrinkage stresses involved were sufficiently high [25].…”

Section: Resultssupporting

confidence: 87%

Microstructural evolution and liquation cracking in the partially melted zone of deposited ERNiCrFe-13 filler metal subjected to TIG refusion

Guo

et al. 2021

Weld World

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The microstructure of ERNiCrFe-13 multipass weld metal has been shown to contain Laves/γ or σ/γ eutectic constituents that can increase susceptibility to solidification and weld metal liquation cracking resulting from the low eutectic reaction temperature. Under poor heat dissipation conditions such as on the edge of large thickness welded components, a partially melted zone (PMZ) may form in the weld metal during multipass welding. The microstructural evolution and liquation cracking susceptibility of this PMZ in ERNiCrFe-13 multipass welds have received little attention. In the present study, a tungsten inert gas (TIG) refusion process is used to simulate a thermal cycle with a long elevated temperature dwell time in order to investigate the microstructural evolution and liquation cracking in the weld metal PMZ. The results show that the eutectic microstructures in the PMZ evolve into three eutectic morphologies after TIG refusion, including long linear chains extending perpendicular to the boundary between the refusion zone and PMZ, skeletal structures, and fine lamellar networks. This evolution contributes to constitutional liquation occurring at the γ/Laves and γ/σ interface. Nb and Mo play a leading role in the constitutional liquation of γ/Laves and γ/σ eutectic microstructures, respectively. Liquation cracking in the PMZ is shown to occur along the linear chain grain boundaries resulting from constitutional liquation.

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Section: Resultssupporting

confidence: 87%

Microstructural evolution and liquation cracking in the partially melted zone of deposited ERNiCrFe-13 filler metal subjected to TIG refusion

Guo

et al. 2021

Weld World

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“…Nowadays, cast structural components are joined together with wrought components to tailor components in more efficient way and to reduce the costs in comparison to single piece castings. This manufacturing procedure, however, results in challenges in the welding process as the microstructure of cast materials is more complex than the wrought one due to the presence of high amount of segregation [4, 5].…”

Section: Introductionmentioning

confidence: 99%

Hot cracking in cast alloy 718

Singh

Andersson

2018

Science and Technology of Welding and Joining

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Hot cracking susceptibility of the Fe-Ni-based precipitation hardening cast superalloy Alloy 718 was studied by Varestraint weldability testing. The effect of two hot isostatic pressing (HIP) treatments commonly employed in the aerospace industry was investigated in reference to the as cast condition. It was found that the heat affected zone (HAZ) liquation cracking susceptibility increased for samples with pre-weld HIP treatments. The as cast condition disclosed the best response for liquation cracking followed by HIP-1120 (1120°C/4h (HIP) + 1050°C/1h and furnace cooling to 650°C/1h in vacuum + 950°C/1h) and HIP-1190 (1190°C/4h (HIP) + 870°C/10h and furnace cooling to 650°C/1h in vacuum + 950°C/1h). The amount of the secondary precipitates and base metal grain size was found to be important parameters influencing the cracking susceptibility. Regarding solidification cracking susceptibility, the three conditions appear to behave similarly.

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“…In energy applications, there will almost certainly be some Ni-alloy components that will need to be welded such as flanges, valve bodies, and headers. [125,135,137] According to Andersson, [152] Ni-alloy welding issues can be broken down into two broad classifications: Geometrical and Metallurgical. The geometrical issues include the shape of the weld pool (tear drop tending to be more crack prone), location of the weld (concave tending to be more crack prone), as well as residual stress and weld defects.…”

Section: E Weldabilitymentioning

confidence: 99%

“…The geometrical issues include the shape of the weld pool (tear drop tending to be more crack prone), location of the weld (concave tending to be more crack prone), as well as residual stress and weld defects. [152] The metallurgical issues mainly include strain age cracking (SAC) and hot cracking. Strain age cracking can result from the stresses induced by thermal expansion/contraction strains and the quick precipitation kinetics of c¢ in the heat affected zone and weld pool.…”

Section: E Weldabilitymentioning

confidence: 99%

Solving Recent Challenges for Wrought Ni-Base Superalloys

Hardy

Detrois

McDevitt

et al. 2020

Metall Mater Trans A

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This paper reviews the status of technology in design and manufacture of new wrought polycrystalline Ni-base superalloys for critical engineering applications. There is a strong motivation to develop new alloys that are capable of operating at higher temperatures to realize improvements in thermal efficiency, which are necessary to achieve environmental targets for reduced emissions of harmful green-house gases. From the aerospace sector, the development of new powder metallurgy and ingot metallurgy alloys is discussed for disk rotor and static applications. New compositions for powder metallurgy contain about 50 to 55 pct of gamma prime (c¢) strengthening precipitates to ensure components operate successfully at temperatures up to 788°C (1450°F). In contrast, new compositions for ingot metallurgy aim to occupy a design space in temperature capability between Alloy 718 and current powder alloys that are in-service, and show levels of c¢ of about 30 to 44 pct. The focus in developing these alloys was design for manufacturability. To complement the aerospace developments, a review of work to understand the suitability of candidate alloys for multiple applications in Advanced-Ultra Supercritical (AUSC) power plants has been undertaken by Detrois, Jablonski, and Hawk from the National Energy Technology Laboratory. In these power plants, steam temperatures are required to reach 700°C to 760°C. The common thread is to develop alloys that demonstrate a combination of high-temperature properties, which are reliant on both the alloy composition and microstructure and can be produced readily at the right price. For the AUSC applications, the emphasis is on high-temperature strength, long-term creep life, phase stability, oxidation resistance, and robust welding for fabrications. Whereas for powder disk rotors in aircraft engines, the priority is enhanced resistance to time-dependent crack growth, phase stability, and resistance to environmental damage, while extending the current strength levels, which are shown by existing alloys, to higher temperatures.

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Review of Weldability of Precipitation Hardening Ni- and Fe-Ni-Based Superalloys

Cited by 8 publications

References 40 publications

Microstructural evolution and liquation cracking in the partially melted zone of deposited ERNiCrFe-13 filler metal subjected to TIG refusion

Microstructural evolution and liquation cracking in the partially melted zone of deposited ERNiCrFe-13 filler metal subjected to TIG refusion

Hot cracking in cast alloy 718

Solving Recent Challenges for Wrought Ni-Base Superalloys

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