PSI - Issue 30

K.V. Stepanova et al. / Procedia Structural Integrity 30 (2020) 167–172 Stepanova K.V., , Petrov P.P., Platonov A.A. / Structural Integrity Procedia 00 (2020) 000–000

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Thus, in the fusion zone of sample deposited by flux-cored wire with 0.7 wt. % total content of REE, metal is formed with grain sizes 22% less than the grain sizes in the UONI 13/55 metal. There is a tendency to decrease the width of the heat-affected zone in all samples with REE compared to the HAZ width of the samples deposited by covered electrode. 4. Conclusions The results of X-ray diffraction analysis showed that tensile internal residual stresses occurred in the weld metal and in the heat-affected zone with rare-earth metals. At the same time, compressive internal residual stresses were found in the weld metal and in the welded joint welded by flux-cored wire with 0.7 wt. % total content of REE, which prevent the formation and propagation of post-weld cracks. The intermetallic inclusions formed grain boundary at the fusion boundary contribute to the hardening of the polygonized substructure. The composition 7 of flux-cored wire (total content of REE is 0.7 wt.%) was selected as the most optimal in terms of the level of stress-strain state, because a metal with a fine grain structure and an increased hardness value is formed with a reduced stress-strain state. The issue of tensile stresses arising during deposition with REE wires of other compositions requires a more detailed study. Acknowledgements This work was supported by Larionov Institute of Physical and Technical Problems of the North of the Siberian Branch of the Russian Academy of Sciences and funded by Ministry of Science and Education of Russian Federation, Project III.28.1.1 in the frames of Program for Basic Research of the Siberian Branch of Russian Academy of Sciences. References Cai, Y.C. Liu, R.P., Wei, Y.H., Cheng, Z.G., 2014. Influence of Y on microstructures and mechanical properties of high strength steel weld metal, Materials and Design 62, 83-90. Dudarev, E. F., 1988. Microscopic deformation and yield strength of polycrystals. TGU, Tomsk, pp. 256. Efimenko, N.G., 2003. Complex assessment of the effect of yttrium on the properties of welds in steels, Avtomaticheskaya svarka 8, 24-27. Efimenko, N.G., 1980. The use of rare earth metals in coverings of welding electrodes, Svarochnoe proizvodstvo 7, 28-29. Genzel, Ch., 2001. X-ray stress analysis in presence of gradients and texture, Advances in X-ray Analysis 44, 247-256. Gorelik, S.S., Skakov, Y.A., Rastorguev, L.N., 1994. X-ray and electron-optical analysis. MISIS, Moscow, pp.328. Hauk, V., 1997. Structural and residual stress analysis by nondestructive methods: Evaluation .Application. Assessment. Elsevier, Amsterdam, pp. 655. Ivanova, V.S., 1986. Mechanics and Synergetics of Fatigue Failure, Fizika, chimiya i mechanika materialov 22, 62-68. Lazko, V.E., Borisov, M.T., Kovalchuk, V.G., Makarov, E. L., 1981. The effect of cerium on the delayed fracture of a high-strength weld, Avtomaticheskaya svarka 2, 27-29. Li, P. Yang, J.C.., Li, Y., 2017. Welding performance of several new rare earth tungsten electrodes, Materials Science Forum 898, 1117-1122. Taylor, A., 1961. X-ray metallography. John Wiley and sons, New York, London, pp. 993. Umanskiy, Y.S., Skakov, Y.A., Ivanov, A.N., Rastorguev, L.N., 1982. Crystallography, radiography and electron microscopy/ Metallurgy, Moscow, pp.632. Welzel, U., 2002. Diffraction analysis of residual stress. Universitat Stuttgart, Stuttgart, pp.169. Welzel, U., Ligot J., Lamparter, P., 2005. Stress analysis of polycrystalline thin films and surface regions by X-ray diffraction, Journal of Applied Crystallography 38, 1-29. Zhang, Z., Z. Wang, Z., Liang, B., Dong, H.B., Hainsworth, S.V., 2007. Effect of CeO 2 on the microstructure and wear behavior of thermal spray welded NiCrWRE coatings, Wear 262, 562-567.