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Enhancing mechanical properties and creep performance of 304H and inconel 617 superalloy dissimilar welds for Advanced Ultra Super Critical power plants
Journal Contribution - Journal Article
This investigation is conducted to find improvements in the mechanical properties of the dissimilar welds between
austenitic stainless steel and Nickel superalloy used in the manufacturing of Advanced Ultra Super Critical
(AUSC) power plants boiler components. Nickel superalloys (IN617) have excellent creep rupture properties, so
they are employed in higher temperature regions (above 700 ◦C) of the boiler. In contrast, austenitic stainless
steel (304H) is used in moderate temperature regions (up to 650 ◦C) part of the boiler, also striking off the
economic balance need. The welding is carried out with manual multipass Gas Tungsten Arc Welding using an
IN617 filler to compare 304H and IN617 weld without and with a buttering layer. Multiple attenuated buttering
material layers are deposited at the 304H side, further machining the butter weld layer to the weld groove and
closure weld to the IN617 part. The buttering technique improves mechanical properties and high-temperature
creep rupture life through microstructure transformation. The dissimilar weld characterization shows a supplementary
dendritic growth layer for the buttering deposition. The tensile strength is found to be 728.214 MPa
with buttering higher than without buttering weld (620.25 MPa). The V-notch Charpy impact toughness value of
the buttered weld sample is 66 J, greater than the non-buttered sample, i.e., 63.25 J. The creep rupture duration
significantly increased with buttering. Strain hardening at higher applied stress helps to resist creep failure even
at higher temperatures.
Journal: International Journal of Pressure Vessels and Piping
ISSN: 0308-0161
Volume: 201
Publication year:2023
Accessibility:Closed