Experience in the Fabrication of Tube Grade 7CrMoVTiB10-10 with Inconel 625 Weld Overlay for Use in Steam Superheaters Exposed to Highly Corrosive Environments

Abstract:

Problems with corrosion in boilers and their parts can be solved by the application of different nickel alloys like 622, 625 or 686 by a variety of welding processes. This solution is used mostly in Waste-to-Energy plants or biomass stations burning waste wood, but it can also be found in the recovery boilers used in the paper industry. The most common material grades include low alloyed boiler steels like 16Mo3, 13CrMo4-5 and 10CrMo9-10. When there is a need to increase steam temperature and pressure more complicated alloys to become a natural choice. This paper focuses on the fabrication experience of welding of 7CrMoVTiB10-10 base tube with Inconel 625 weld overlay and presents a welding solution of matching filler metal used for root pass and S Ni 6625 filler metal for a fill-up and the cap performing a full strength weld without the need of overlay peeling and manual tie-in overlay. This method of welding saves a lot of time during execution in the workshop and on-site during installation and assures much better quality in the end. All examinations were performed to allow welding procedure qualification according to ASME and EN standards.

• Periodical: Key Engineering Materials (Volume 966)
• Pages: 19-24
• DOI: https://doi.org/10.4028/p-5Zn4es
• Online since: November 2023
• Authors: Miachal Urzynicok*, Hanna Purzynska, Krzysztof Kwiecinski
• Keywords: 7CrMoVTiB10-10, Bainitic Steel, Boilers, Creep Resistant Steel, Inconel 625, Superheaters, Weld Overlay, Welding

References

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DOI: 10.2478/amm-2013-0056

[2] EN 10216-2:2013+A1:2019. Seamless steel tubes for pressure purposes. Technical delivery conditions - Non-alloy and alloy steel tubes with specified elevated temperature properties.

DOI: 10.3403/02591066

[3] ISO 5817:2014. Welding — Fusion-welded joints in steel, nickel, titanium and their alloys (beam welding excluded) — Quality levels for imperfections.

DOI: 10.3403/30143072

[4] ISO 6892-1:2019. Metallic materials. Tensile testing. Part 1: Method of test at room temperature.

[5] ISO 6892-2:2018 Metallic materials. Tensile testing. Part 2: Method of test at elevated temperature.

[6] ISO 5173:2009. Destructive tests on welds in metallic materials. Bend tests.

[7] ISO 6507-1:2018. Metallic materials. Vickers hardness test. Part 1: Test method.