Weld Solidification Cracking in Solid-Solution Strengthened Ni-Base Filler Metals

Lippold, John C.; Sowards, Jeffrey W.; Murray, George M.; Alexandrov, Boian; Ramírez, Antonio J.

doi:10.1007/978-3-540-78628-3_9

Cited by 30 publications

(19 citation statements)

References 3 publications

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“…Rather, high stroke rates for Varestraint testing are the standard for many testing facilities around the world (see Table 1). However, high stroke rates have been reported to supress potential back-filling of cracks, making Varestraint testing less suitable for assessment of materials which might exhibit crack healing [52,53]. Testing at different strain rates was therefore carried out in search for further insight into the crack healing potentials of the examined materials.…”

Section: Standard Mvt Proceduresmentioning

confidence: 99%

Surface- and volume-based investigation on influences of different Varestraint testing parameters and chemical compositions on solidification cracking in LTT filler metals

et al. 2020

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The subject of this study is how, and to what extent, Varestraint/Transvarestraint test results are influenced by both testing parameters and characteristics of evaluation methods. Several different high-alloyed martensitic LTT (low transformation temperature) filler materials, CrNi and CrMn type, were selected for examination due to their rather distinctive solidification cracking behaviour, which aroused interest after previous studies. First, the effects of different process parameter sets on the solidification cracking response were measured using standard approaches. Subsequently, microfocus X-ray computer tomography (μCT) scans were performed on the specimens. The results consistently show sub-surface cracking to significant yet varying extents. Different primary solidification types were found using wavelength dispersive X-ray (WDX) analysis conducted on filler metals with varying Cr/Ni equivalent ratios. This aspect is regarded as the main difference between the CrNiand CrMn-type materials in matters of cracking characteristics. Results show that when it comes to testing of modern highperformance alloys, one set of standard Varestraint testing parameters might not be equally suitable for all materials. Also, to properly accommodate different solidification types, sub-surface cracking has to be taken into account.

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Section: Standard Mvt Proceduresmentioning

confidence: 99%

Surface- and volume-based investigation on influences of different Varestraint testing parameters and chemical compositions on solidification cracking in LTT filler metals

et al. 2020

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“…Its alloying elements are chosen in a way increasing the mechanical properties and improving high temperature corrosion, creep resistance, fracture toughness, and structural stability [2,3].…”

Section: Introductionmentioning

confidence: 99%

“…Since the amount of the elements such as Al, Hf, Ta, and Ti is very low in Hastelloy X, formation of γ ' does not occur in structure of this alloy. Microstructure composition of the alloy contains an austenite matrix and M 6 C and M 23 C 6 carbides enriched in Mo and Cr elements, respectively [3].…”

Section: Introductionmentioning

confidence: 99%

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The Effect of Repair Welding Number on Microstructure of Hastelloy X Fabricated via TIG Process

Abedi¹,

Sabet

Razavi³

2016

IJMSA

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Abstract:The effect of repair welding number on microstructure of the hastelloy X fabricated via TIG process was investigated. The SEM, EDS and OM were used to determine mechanical properties and the microstructure of HAZ zone, respectively. Results showed that the grain size of base metal determined by OM and SEM was 64.11 µm with M 6 C and M 23 C 6 carbides (6.16, 18.71 µm respectively). Also, using welding for three times caused increase of grain size (15%, 22%, 26% respectively) and the heat input made some carbides dissolve. The grain growth through HAZ zone venially affected the strength of alloy. The results of tensile test demonstrated that UTS increased by repair welding, 1%, 2% and 3% respectively. As the UTS of base metal was 727 MPa, the fracture phenomenon occurred. Furthermore, repair welding of mentioned alloy did not exceed more than three times.

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“…Backfilling is observed in weld metals to promote partial or entire crack healing due to sufficient fraction of liquid at the end of solidification that flows into newly formed cracks or voids (Refs. [6][7][8][9]. Differences among heats were also found in the nature of constituents in the solidification microstructure that correlated with differences in nitrogen and possibly carbon content (Ref.…”

Section: Introductionmentioning

confidence: 99%

Effect of Nitrogen on Solidification Cracking Resistance in ERNiCr-3 Weld Metal

2018

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Additions of nitrogen were made to ERNiCr-3 (FM 82) weld metal to investigate the effect on weld metal microstructure and solidification cracking susceptibility. Weld samples were prepared with different argon-nitrogen shielding gas mixtures to produce nitrogen variations in the weld metal. The cast pin tear test (CPTT) was then used to evaluate solidification cracking susceptibility as a function of weld metal nitrogen content. Phase fraction and composition of constituents in the final solidification microstructure were characterized via optical and electron microscopy. Thermodynamic (Scheil) calculations were performed to determine the phase formation during solidification, associated solidification path, and solidification temperature range. Solidification cracking susceptibility was found to increase significantly with increasing nitrogen content. The overall amount of second phase in the solidified microstructure increased when nitrogen was added to the weld metal. Small skeletal constituents in the interdendritic regions, primarily Nb-rich carbides (NbC), were more frequently observed with increasing weld metal nitrogen content. Larger cuboidal Ti-rich nitrides (TiN) and carbonitrides (Ti, Nb)(N, C) were found only when nitrogen was added to the weld metal. Their location in dendrite core regions indicates formation during an earlier stage of the solidification process. Scheil calculations confirmed the strong effect of nitrogen additions on the amount and sequence of phase formation during solidification of ERNi-Cr-3 weld metal. High nitrogen levels ( 100 ppm) facilitate primary nitride formation prior to the solidification of the gamma () dendrites, and increase the amount of phase constituents in the solidification microstructure. The presence of nitrogen also shifts the start of the eutectic /NbC formation at the end of solidification to lower temperatures, which results in an increase in the solidification temperature range. This occurs at much lower nitrogen levels ( 25 ppm) and correlates with the observed increase in solidification cracking susceptibility.

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Weld Solidification Cracking in Solid-Solution Strengthened Ni-Base Filler Metals

Cited by 30 publications

References 3 publications

Surface- and volume-based investigation on influences of different Varestraint testing parameters and chemical compositions on solidification cracking in LTT filler metals

Surface- and volume-based investigation on influences of different Varestraint testing parameters and chemical compositions on solidification cracking in LTT filler metals

The Effect of Repair Welding Number on Microstructure of Hastelloy X Fabricated via TIG Process

Effect of Nitrogen on Solidification Cracking Resistance in ERNiCr-3 Weld Metal

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