Abstract
This study aimed to determine the mechanism of δ-ferrite retention in the coarse-grained HAZ (CGHAZ) of Grade 91 steel dissimilar metal welds (DMWs) with Ni-based filler metals. This phenomenon was investigated in four DMWs made with cold-wire gas tungsten arc process using Alloys 625, 617, 82, and P87 filler metals. A narrow band of δ-ferrite grains was identified in the CGHAZ in all welds. It was hypothesized that δ-ferrite retention was caused by local carbon depletion in the CGHAZ, which was validated through extensive thermodynamic and kinetic simulations and metallurgical characterization. Carbon diffusion across the fusion boundary was driven by the carbon chemical potential gradient between Grade 91 steel and the Ni-based filler metals, which was facilitated by long high-temperature dwell times resulting from a difference in heat capacity and thermal conductivity between the base and filler metals. A linear relationship was established between the amounts of retained δ ferrite and the predicted carbon depletion in the CGHAZ of each DMW. Alloy 625 filler metal generated the largest extent of carbon depletion and the most retained δ ferrite, followed by Alloys 617, 82, and P87. The carbon depletion resulted in local softening of the CGHAZ martensite.
Similar content being viewed by others
References
F. Masuyama and J. P. Shingledecker: Procedia Engineering, 2013, vol. 55, pp. 314-325.
K. Maruyama, K. Sawada, and J. I. Koike: ISIJ International, 2001, vol. 41, pp. 641-653.
C. Pan and Z. Zhang: Materials Characterization, 1996, vol. 36, pp. 5-10.
J. N. DuPont: International Materials Reviews, 2012, vol. 57, pp. 208-234.
R. Anand, C. Sudha, T. Karthikeyan, A. L. E. Terrance, S. Saroja, and M. Vijayalakshmi: Journal of Materials Science, 2008, vol. 44, pp. 257-265.
R. Anand, C. Sudha, T. Karthikeyan, A. L. E. Terrance, S. Saroja, and M. Vijayalakshmi: Transactions of the Indian Institute of Metals, 2008, vol. 61, pp. 483-486.
R. Viswanathan, R. I. Jaffee, and J. Dimmer: Annual Conference on Materials for Coal Conversion and Utilization (Proceedings), 1982, pp. 439–70.
D. Gandy and K. Coleman, Alternative filler materials for DMWs involving P91 materials, in EPRI Fifth International Conference—Advances in Materials Technology for Fossil Power Plants, Marco Island, Fl, 2007, pp. 940–67.
J. A. Siefert, J. M. Sanders, J. M. Tanzosh, W. F. Newell Jr, and J. P. Shingledecker: Materials at High Temperature, 2010, vol. 27, pp. 243-252.
M. F. Dodge, H. B. Dong, and M. F. Gittos: Materials Research Innovations, 2014, vol. 18, pp. S4907-S4913.
J. Clark: Ph.D. Dissertation, EFET EngD Centre, UON, Nottingham, UK, 2015.
J. Frei, B. T. Alexandrov, and M. Rethmeier: Welding in the World, 2016, vol. 60, pp. 459-473.
M. K. Samal, M. Seidenfuss, E. Roos, and K. Balani: Engineering Failure Analysis, 2011, vol. 18, pp. 999-1008.
B. T. Alexandrov, J. C. Lippold, J. W. Sowards, A. T. Hope, and D. R. Saltzmann: Welding in the World, 2012, vol. 57, pp. 39-53.
G. J. Brentrup, B. S. Snowden, J. N. DuPont, and J. L. Grenestedt: Welding Journal, 2012, vol. 91, pp. 252S-259S.
Cracking in Thick-Section Dissimilar Metal Welds—Case Studies, EPRI, Palo Alto, CA. 2015.
J. Siefert, J. Parker, and T. Totemeier, 2016, p. V005T12A009.
M.W. Kuper, B.T. Alexandrov, M.J. Mills, and D.J. Burgess, Dissimilar metal welds in grade 91 steel, in 8th International Conference on Advances in Materials Technology for Fossil Power Plants, 2016, pp. 1199–1206.
B. Gsellmann, D. Halici, B. Krenmayr, C. Poletti, and B. Sonderegger, Thermomechanical investigation of the production process of a creep resistant martensitic steel, in 20th International ESAFORM Conference on Material Forming, ESAFORM 2017, 2017.
P. H. S. Cardoso, C. Kwietniewski, J. P. Porto, A. Reguly, and T. R. Strohaecker: Materials Science and Engineering A, 2003, vol. 351, pp. 1-8.
P. Wang, S. P. Lu, N. M. Xiao, D. Z. Li, and Y. Y. Li: Materials Science and Engineering A, 2010, vol. 527, pp. 3210-3216.
D. Carrouge, H. K. D. H. Bhadeshia, and P. Woollin: Science and Technology of Welding and Joining, 2004, vol. 9, pp. 377-389.
K. Anderko, L. Schäfer, and E. Materna-Morris: Journal of Nuclear Materials, 1991, vol. 179-181, pp. 492-495.
C. Pandey, M. M. Mahapatra, P. Kumar, and N. Saini: Materials Science and Engineering: A, 2018, vol. 712, pp. 720-737.
S. Kobayashi, K. Sawada, T. Hara, H. Kushima, and K. Kimura: Materials Science and Engineering: A, 2014, vol. 592, pp. 241-248.
M. L. Santella, R. W. Swindeman, R. W. Reed, and J. M. Tanzosh, Martensite transformation, microsegregation, and creep strength of 9 Cr-1 Mo-V steel weld metal, in ASM Proceedings of the International Conference: Trends in Welding Research, 2002, pp. 713–18.
S. H. Ryu and J. Yu: Metallurgical and Materials Transactions A: Physical Metallurgy and Materials Science, 1998, vol. 29, pp. 1573-1578.
H. Schneider: Foundry Trade J., 1960, vol. 108, pp. 562-563.
F.C. Hull: Weld. J. (Miami, Fla), 1973, vol. 52, pp. 193s–203s.
M. Tamura, M. Inohara, K. Kusunoki, and Y. Tsuchida: Japan Iron and Steel Institute, 1984, vol. 70, p. S524.
J. Oñoro: Journal of Materials Processing Technology, 2006, vol. 180, pp. 137-142.
B. Arivazhagan, G. Srinivasan, S. K. Albert, and A. K. Bhaduri: Fusion Engineering and Design, 2011, vol. 86, pp. 192-197.
N. H. Jung, J. H. Ann, M. J. Lee, N. H. Kang, and K. M. Cho: Journal of Korean Institute of Metals and Materials, 2018, vol. 56, pp. 93-102.
J. M. Sosa, D. E. Huber, B. Welk, and H. L. Fraser: Integrating Materials and Manufacturing Innovation, 2014, vol. 3, p. 10.
J. O. Andersson, T. Helander, L. Höglund, P. F. Shi, and B. Sundman: Calphad, 2002, vol. 26, pp. 273-312.
H. Larsson and L. Höglund: Calphad, 2009, vol. 33, pp. 495-501.
C. Wells, W. Batz, and R. F. Mehl: Trans. AIME, 1950, vol. 188.
C. A. Wert: Physical Review, 1950, vol. 79, pp. 601-605.
C. Pandey, M. M. Mahapatra, P. Kumar, N. Saini, J. G. Thakre, R. S. Vidyarthy, et al.: Archives of Civil and Mechanical Engineering, 2018, vol. 18, pp. 713-722.
Author information
Authors and Affiliations
Corresponding author
Additional information
Publisher's Note
Springer Nature remains neutral with regard to jurisdictional claims in published maps and institutional affiliations.
Manuscript submitted October 30, 2018.
Rights and permissions
About this article
Cite this article
Kuper, M.W., Alexandrov, B.T. Retention of Delta Ferrite in the Heat-Affected Zone of Grade 91 Steel Dissimilar Metal Welds. Metall Mater Trans A 50, 2732–2747 (2019). https://doi.org/10.1007/s11661-019-05182-4
Received:
Published:
Issue Date:
DOI: https://doi.org/10.1007/s11661-019-05182-4