PSI - Issue 20

Sivtsev M.N. et al. / Procedia Structural Integrity 20 (2019) 148–153

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Sivtsev M.N. et al. / Structural Integrity Procedia 00 (2019) 000 – 000

As noted earlier Chernov D.K. (1869) and Saraev Yu.N., Bezborodov V.P. (2012), obtaining the fine-grained structure of the cast weld metal allows to improve its mechanical properties, thereby increasing its technological strength, corrosion resistance and reliability. In the work of Morozov V.P. (2006) it is shown that obtaining a fine grained structure of the weld can be achieved by applying pulse-periodic heat input to the weld pool. In the works of Sarayev Yu.N. (2015) it was noted that programmable heat input into the welding zone, monitoring the melting and transfer processes of each drop of electrode metal contributes to the formation of a finely dispersed structure in the heat-affected zone. Thus, it was revealed that when surfacing with modulated current, it is really possible to form metal with uniform fine grain structure in the heat-affected zone. 4. Conclusions 1. Using adaptive pulse-arc welding under positive temperature (+ 21 0 C) leads to a decrease in the HAZ than using a stationary welding. Moreover, increasing the duration of the pause adaptive pulse-arc welding decreasing by size of the HAZ to 2 times as compared with the stationary welding mode. At the same time decreasing the size of the HAZ by increasing the pulse duration of the pause in the welding conditions at low temperatures, it is not so obvious than when using adaptive pulse-arc welding mode under positive temperatures. 2. It is shown that by using the adaptive pulse-arc welding is 1.2 - 1.3 times decreasing the grain size of the HAZ at positive and at negative temperatures. Acknowledgements This research has been supported by Ministry of Science and Education of Russian Federation (Project III.28.1). References Chernov, D.K., 1869. Notes of the Russian Technical Society, pp. 109. GOST 5639-82, 2003. Steel and steel alloys. Methods for detection and determination of grain size. IPK Izdatelstvo standartov, Moscow, 16 pp. GOST 33258-2015, 2016. Pipe fittings. Surfacing and quality control of deposited surfaces. Standartinform, Moscow, 46 pp. Paton, B.E., Sarayev, J.N., Lebedev, V.A., 2013. Prospects for the development and practical application of pulse welding and surfacing technologies to improve operational safety-duty steel structures, Welding and related technologies - present and future: Tez. stand. rep. Kyiv, 91-97. Larionov, V.P., 1998. Welding problems and ductile-brittle transition. Novosibirsk, 1998, pp. 593. Morozov ,V.P., 2006. Analysis of the conditions for the formation of the fine grain structure during crystallization of the metal of the weld pool with the imposition of external periodic disturbances. Izvestiya vuzov 8, 41-54. Sarayev, Yu.N., 2010. Justification of the concept of improving the safety and survivability of technical systems operated in the regions of Siberia and the Far North, based on the use of adaptive pulsed welding technologies. Tyazheloe mashinovedenie 8, 14-19. Sarayev, Yu.N. et al., 2015. Controlling of the structure and properties of welded joints of technical systems of critical use by adaptive pulsed-arc welding methods. Voprosy materialovedeniya 1, 127-132. Sarayev, Yu.N., Bezborodov, V.P., 2012. Effect of energy parameters of the welding process on the structure and properties of welded joints of low alloy steels. Svarochnoe proizvodstvo 8, 3-5. Sivtsev, M.N., Sleptsov, G.N., 2014. Investigation of the structure changes welds at different technological parameters of the welding alloy steels. Metallovedenie i termicheskaya obrabotka metallov 704, 40-44.