Abstract
In waste incinerators and petrochemical plants, one encounters dissimilar weld joints of superalloys and special steels. The operating conditions are such that weld joints are exposed to high temperatures and deposition of salts takes place on the weld joints. In addition, experience shows that many failures take place at the weld joints. Hence it becomes imperative that hot corrosion behaviour of such weldments is studied and underlying mechanisms understood, so that suitable remedial measures can be identified. The present study addresses air oxidation and hot corrosion behaviour of dissimilar laser welded joints of Ni–Fe-based superalloy 825 and AISI 321 under K2SO4 + 60% NaCl at 650°C. The result analysis for reaction products, phase changes the distribution of alloying elements in the corrosion product(s) and the underlying substrate of the hot corroded samples were discussed in detail from the results obtained from cross sectional OM, SEM and XRD, X-ray mapping and EDS point analysis. Corrosion kinetics of the weldment is obtained by thermo-gravimetric technique. Sulphide and dichromate phases form additionally during hot corrosion; the latter, with low relatively low boiling points, may be contributing to loss of Cr from the surface and weight loss.
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REFERENCES
I. A. Choudhury and M. A. El-Baradie, “Machinability of nickel-base super alloys: a general review,” J. Mater. Process. Technol. 77, 278–284 (1998).
M. Arivarasu, Roshith, R. Padmanaban, S. Thirumalini, K. V. Phani Prabhakar, and G. Padmanabham, “Investigations on metallurgical and mechanical properties of CO2 laser beam welded Alloy 825,” Can. Metall. Quart. 56, 232–244 (2017).
H. Aytekin and Y. Akçin, “Characterization of borided Incoloy 825 alloy,” Mater. Des. 50, 515–521 (2013).
K. Guan, X. Xu, H. Xu, and Z. Wang, “Effect of aging at 700°C on precipitation and toughness of AISI 321 and AISI 347 austenitic stainless-steel welds,” Nucl. Eng. Des. 235, 2485–2494 (2005).
K. S. Min and S. W. Nam, “Correlation between characteristics of grain boundary carbides and creep–fatigue properties in AISI 321 stainless steel,” J. Nucl. Mater. 322, 91–97 (2003).
H. S. Hosseini, M. Shamanian, and A. Kermanpur, “Microstructural and weldability analysis of Inconel617/AISI 310 stainless steel dissimilar welds,” Int. J. Pressure Vessels Piping 144, 18–24 (2016).
H. Naffakh, M. Shamanian, and F. Ashrafizadeh, “Dissimilar welding of AISI 310 austenitic stainless steel to nickel-based alloy Inconel 657,” J. Mater. Process. Technol. 209, 3628–3639 (2009).
M. Arivarasu, M. Venkatesh Kannan, K. Devendranath Ramkumar, and N. Arivazhagan, “Hot-corrosion resistance of dissimilar AISI 4340 and AISI 304L weldments in the molten salt environment at 600°C,” Corros. Eng. Sci. Technol. 52, 114–123 (2017).
G. Sayiram and N. Arivazhagan, “Microstructural characterization of dissimilar welds between Incoloy 800H and 321 austenitic stainless steel,” Mater. Charact. 102, 180–188 (2015).
G. J. Ram, A. V. Reddy, K. P. Rao, G. M. Reddy, and J. S. Sundar, “Microstructure and tensile properties of Inconel 718 pulsed Nd-YAG laser welds,” J. Mater. Process. Technol. 167, 73–82 (2005).
J. Kangazian and M. Shamanian, “Mechanical and microstructural evaluation of SAF 2507 and incoloy 825 dissimilar welds,” J. Manuf. Processes. 26, 407–418 (2017).
N. Eliaz, G. Shemesh, and R. M. Latanision, “Hot corrosion in gas turbine components,” Eng. Failure. Anal. 9, 31–43 (2002).
S. M. Muthu and M. Arivarasu, “Air oxidation and hot corrosion behavior of bare and CO2 laser-welded superalloy A-286 at 700°C,” Trans. Indian Inst. Met. 72, 1607–1612 (2019).
S. S. Chatha, H. S. Sidhu, and B. S. Sidhu, “High temperature hot corrosion behaviour of NiCr and Cr3C2–NiCr coatings on T91 boiler steel in an aggressive environment at 750°C,” Surf. Coat. Technol. 206, 3839–3850 (2012).
S. M. Muthu and M. Arivarasu, “Investigations of hot corrosion resistance of HVOF coated Fe based superalloy A-286 in simulated gas turbine environment,” Eng. Failure Anal. 107, 104224 (2020).
T. S. Sidhu, S. Prakash, and R. D. Agrawal, “Performance of high-velocity oxyfuel-sprayed coatings on an Fe-based superalloy in Na2SO4–60% V2O5 environment at 900°C part II: Hot corrosion behavior of the coatings,” J. Mater. Eng. Perform. 15, 130–138 (2006).
P. R. Hari, N. Arivazhagan, M. N. Rao, and A. H. V. Pavan, “Hot corrosion studies on alloy 617 OCC in the context of its use in advanced ultra-supercritical (A-USC) power plants,” Trans. Indian Inst. Met., 70, 775–781 (2017).
D. Mudgal, S. Singh, and S. Prakash, “Hot corrosion behavior of bare, Cr3C2–(NiCr) and Cr3C2–(NiCr) + 0.2 wt % Zr coated SuperNi 718 at 900°C,” J. Mater. Eng. Perform. 24, 1–15 (2015).
ACKNOWLEDGMENTS
The authors would also like to thank Lab in charges of Materials Engineering Technology Laboratory and Advance Materials processing laboratory, VIT—Vellore for providing all the facilities to carry out the research work. The authors sincerely thank Mr. Phani Prabhakar K.V., who helped as carrying out the CO2 laser welding process, at the International Advanced Research Centre for Powder Metallurgy and New Materials (ARCI), Balapur, Hyderabad.
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The authors thank VIT for providing “VIT SEED GRANT” for carrying out this research work.
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Muthu, S.M., Arivazhagan, N., Rao, M.N. et al. Oxidation and Hot Corrosion Behaviour of Ni-Based Superalloy 825 and AISI 321 Dissimilar Laser Weldment in K2SO4–60% NaCl Molten Salt Environment at 650°C. Phys. Metals Metallogr. 123, 1306–1316 (2022). https://doi.org/10.1134/S0031918X21100525
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DOI: https://doi.org/10.1134/S0031918X21100525