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2023 №05 (03) DOI of Article
10.37434/tpwj2023.05.04
2023 №05 (05)

The Paton Welding Journal 2023 #05
The Paton Welding Journal, 2023, #5, 22-28 pages

Technology of MIG welding of chromium steel of martensitic grade CA-6NM

A.R. Gavryk1, A.K. Tsaryuk1, I.G. Osypenko1, O.V. Lynnyk2, O.V. Vavilov2, O.G. Kantor2

1E.O. Paton Electric Welding Institute of the NASU.. 11 Kazymyr Malevych Str., 03150, Kyiv, Ukraine. E-mail: tsaryuk@paton.kiev.ua
2JSC “Ukrainian Energy Machines”. 199 Moskovsky Ave., 61037, Kharkiv, Ukraine. E-mail: office@ukrenergymashines.com

Abstract
The weldability of the martensitic steel CA-6NM was investigated and the fundamental technology of its mechanized welding in a mixture of shielding gases was developed according to the requirements for the manufacture of critical parts and assemblies of the hydro-turbine equipment, as well as rewelding of casting defects. According to the strength level of the steel, the welding wire Thermanit 13/04 Si of a solid cross-section with a diameter of 1.2 mm and one of the variants of the protective mixture Mix 1 (82 % Ar + 18 % CO2) were selected and comprehensively investigated according to EN 12072/G 134 (Germany). It was established that in order to prevent the formation of cold cracks in welded joints, it is necessary to perform welding of this steel with a preliminary and accompanying heating up to 150…200 °C and a mandatory postweld tempering at a temperature of 600 °C. The developed technology provides a significant improvement in mechanical properties of welded joints of weld metal (by 30…35 % higher than specified by the requirements to the level of the base metal of chromium steel CA-6NM). Certification of the technology was carried out and recommendations for its production use at the JSC “Ukrainian Energy Machines” were worked out. 17 Ref., 5 Tabl., 8 Fig.
Keywords: mechanized welding, martensitic steel, mixture of shielding gases, diffusion hydrogen, cold cracks, mechanical properties, structure

Received: 11.04.2023
Accepted: 29.06.2023

References

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Suggested Citation

A.R. Gavryk, A.K. Tsaryuk, I.G. Osypenko, O.V. Lynnyk, O.V. Vavilov, O.G. Kantor (2023) Technology of MIG welding of chromium steel of martensitic grade CA-6NM. The Paton Welding J., 05, 22-28.