The microstructure and hardness of the weld joints of DOMEX 700 steel were investigated. As a result, the optimization of the parameters of robotic arc welding in the environment of protective gases was carried out taking into account the size of the energy per unit length. The optimum modes of welding were determined. The size of the deterioration area, where there is a decrease in hardness in comparison with the main metal, for a thickness of 6 mm is 2.36 mm, and for a thickness of 3 mm is 1.51 mm. The parameters of the robotic welding process in the arc mode in the environment of protective gases for the investigated thicknesses of the DOMEX 700 steel were recommended. As a result, the energy-saving conditions for welding performing were achieved ensuring the required technological strength.
 V.M. Palash , et al., “Osoblyvosti budovy zvarnoho z’iednannia zi stali typu 35 XM, z austenitnym shvom” [“Features of the structure of welded joints made of steel type 35 XM, with austenitic suture”], Visnyk Natsionalnoho universytetu “Lvivska politekhnika” “Dynamika, mitsnist ta proektuvannia mashyn i pryladiv” [Bulletin of Lviv Polytechnic National University “Dynamics, strength and design of machines and devices”], no. 866, pp. 21–25, 2017. [in Ukrainian].
 A. R. Dziubyk and L. V. Dziubyk, “Zabezpechennia enerhooshchadnykh umov formuvannia zvarnykh z’iednan pidvyshchenoi mitsnosti” [“Provision of energy-saving conditions for the formation of welded joints of high strength”], Tezy dopovidei II-i Mizhnarodnoi naukovo-tekhnichnoi konferentsii “Enerhooshchadni mashyny i tekhnolohii”[ Abstracts of the 2nd International Scientific and Technical Conference “Energy-saving Machines and Technologies”], Kyiv, Ukraine, 2015, p. 78. [in Ukrainian].
 M. H. Yefimenko, “Zvariuvannia spetsialnykh stalei i splaviv” [“Welding of special steels and alloys”], Kharkiv, Ukraine: FOP Marakin I.V. Publ., 2007. [in Ukrainian].
 E. L. Makarov, “Holodnye treshhiny pri svarke legirovannyh stalej” [“Cold cracks in the welding of alloy steels”], Moscow, Russia: Mashinostroenie Publ., 1981. [in Russian].
 A. R. Dzyubyk, et al., “Pidvyshchennia efektyvnosti zvariuvannia mahistralnykh truboprovodiv pry yikh ekspluatatsii ta remonti” [“Increasing the efficiency of welding of main pipelines during their operation and repair”], Lviv, Ukraine: Spolom Publ., 2013. [in Ukrainian].
 A. R. Dzyubyk, et al., “Influence of Residual Stresses on the Limit Equilibrium of a Pipeline with Internal Crack of Arbitrary Configuration”, Materials Science, vol.52, no.1, pp. 89–98, July, 2016. https://doi.org/10.1007/s11003-016-9930-4
 L. M. Lobanov, et al., “Osobennosti protekanija termodeformacionnyh processov pri dugovoj svarke vysokoprochnyh stalej” [“Features of the course of thermoformation processes during arc welding of high strength steels”], Avtomaticheskaja svarka [Automatic welding], no. 3, pp.13–17, 1999. [in Russian].
 L. M. Lobanov, et al., “Obrazovanie holodnyh treshhin v svarnyh soedinenijah vysokoprochnyh stalej s predelom tekuchesti 350-850 MPa” [“Formation of cold cracks in welded joints of high-strength steels with a yield strength of 350-850 MPa”], Avtomaticheskaja svarka [Automatic welding], no.7, pp. 8–13, 2013. [in Russian].
 V. M. Palash, et al., “Osoblyvosti zvariuvannia spetsialnykh vysokomitsnykh stalei bez zastosuvannia poperednoho pidihrivannia” [“Features of welding of special high-strength steels without the use of preheating”], Materialy 12-ho Mizhnarodnoho sympoziumu ukrainskykh inzheneriv-mekhanikiv u Lvovi [Proceedings of the 12th International Symposium of Ukrainian Mechanical Engineers in Lviv], Lviv, Ukraine, 2015, pp. 101–102. [in Ukrainian].
 M. H. Shorshorov and V. V. Belov, “Fazovye prevrashhenija i izmenenie svojstv stali pri svarke” [“Phase transformations and changes in the properties of steel during welding”], Moscow, Russia: Nauka Publ., 1972. [in Russian].
 SSAB SWEDISH STEEL. Domex range of hot-rolled high strength sheet steel. Sweden, 24 p., 2015.
 A. R. Dzyubyk, et al., “Zabezpechennia tekhnolohichnoi mitsnosti zvarnykh stykiv obsadnykh trub” [“Provision of technological strength of welded joints of casing pipes”], “Avtomatyzatsiia vyrobnychykh protsesiv u mashynobuduvanni ta pryladobuduvanni” ["Automation of production processes in mechanical engineering and instrument making"], no. 50, pp. 94–102, 2016. [in Ukrainian].
 K. L. Kulikovskij and V. Ja. Kuper, “Metody i sredstva izmerenij” [“Methods and measuring measurement”], Moscow, Russia: Jenergoatomizdat Publ., 1986. [in Russian].
 V. M. Palash, “Metaloznavchi aspekty zvarnosti zalizovuhletsevykh splaviv” [“Metallurgical aspects of welded iron-carbon alloys”], Lviv, Ukraine: KINPATRI LTD Publ., 2003. [in Ukrainian].