Microstructure characteristic and mechanical property of pulsed laser lap-welded nickel-based superalloy and stainless steel

Zhou, Siyu; Chai, Dongsheng; Yu, Jingling; Ma, Guangyi; Wu, Dongjiang

doi:10.1016/j.jmapro.2016.11.010

Cited by 39 publications

(10 citation statements)

References 17 publications

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“…The higher magnification SEM images further revealed the presence of fine, needle shape, cellular substructure colonies, with different growth directions due to Chessboard scan strategy, as shown in figure 4a. Cellular microstructures have been previously reported during laser welding when the solidification process experiences rapid cooling rates similar to SLM process [15,16]. The cells oriented in the same crystallographic orientation belong to the same grain, and usually cross the melt pool boundaries due to the partial re-melting involved.…”

Section: Microstructure Characterizationmentioning

confidence: 84%

Microstructure and Mechanical Properties of 316L Stainless Steel Fabricated Using Selective Laser Melting

et al. 2019

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ABSTRACTThe microstructure homogeneity and variability in mechanical properties of 316L stainless steel components fabricated using selective laser melting (SLM) have been investigated. The crack free, 99.9% dense samples were made starting from SS316L alloy powder, and the melt pool morphology was analysed using optical and scanning electron microscopy. Extremely fast cooling rates after laser melting/solidification process, accompanied by slow diffusion of alloying elements, produced characteristic microstructures with colonies of cellular substructure inside grains, grown along the direction of the principal thermal gradient during laser scanning. In some areas of the microstructure, a significant number of precipitates were observed inside grains and at grain boundaries. Micro hardness measurements along the build direction revealed slight but gradual increase in hardness along the sample height. Uniaxial tensile tests of as manufactured samples showed the effect of un-melted areas causing scatter in room-temperature mechanical properties of samples extracted from the same SLM build. The ultimate tensile strength (UTS) varied from 458MPa to 509MPa along with a variation in uniform elongation from 3.3% to 14.4%. The UTS of a sample exposed to the Cl- rich corrosion environment at 46oC temperature revealed a similar strength as of the original sample, indicating good corrosion resistance of SLM samples under those corrosion conditions.

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Section: Microstructure Characterizationmentioning

confidence: 84%

Microstructure and Mechanical Properties of 316L Stainless Steel Fabricated Using Selective Laser Melting

et al. 2019

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“…In the present investigation, enhancement of Mo and depletion of Ni and Fe are observed in the GTA weldment. 37 In the GTA welding technique, the high heat supply and lower cooling rate lead to the larger dendritic arm spacing with coarser grains in the FZ. At the end of the solidification, the space between the dendrites is the preferred site for the segregation of alloying elements.…”

Section: Resultsmentioning

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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“…In order to conduct the experiment, CO2 laser welding was used to weld the parts together. However, two different thicknesses of highstrength steel, 1.6 mm and 2.0 mm, The process accuracy was examined in great depth, and the laser welding procedure was able to combine even the most complex of materials [33]. The weld bead profile and the heat-affected zone were analysed for P92 (Cr-W-Mo-V) steel.…”

Section: Introductionmentioning

confidence: 99%

CO2 Laser Study of SS316 and Ni201 Dissimilar Metal Joining

2022

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Dissimilar metal welded joints are commonly used in the nuclear sector to connect pressure vessel ferritic steel pipe nozzles to austenitic stainless steel safe-end pipes. Stainless Steel 316 and Nickel 201 dissimilar joints are focused on by utilising a 4KW CO2 laser welding machine in this study. Mechanical parameters such as ultimate tensile strength (UTS) and hardness survey were used to identify a high-quality welded junction. The tensile stress was found to be 412 Mpa, and the fracture occurred outside the weld zone on the nickel side. The tensile test shows that the weld was strong enough to break through the base metal. The profile of the weld bead is critical to ensure that it is a strong weld junction. Some delta ferrite has been observed in the interdendritic zone in microstructure studies, along with columnar grains during solidification, all of which point to successful fusing in the joint between the two dissimilar metals. With the 4 kW CO2 laser welding machine, it is possible to join materials that are completely different from each other.

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Microstructure characteristic and mechanical property of pulsed laser lap-welded nickel-based superalloy and stainless steel

Cited by 39 publications

References 17 publications

Microstructure and Mechanical Properties of 316L Stainless Steel Fabricated Using Selective Laser Melting

Microstructure and Mechanical Properties of 316L Stainless Steel Fabricated Using Selective Laser Melting

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

CO2 Laser Study of SS316 and Ni201 Dissimilar Metal Joining

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