## 1 Introduction
An experimental research of welding effects on tensile characteristics of the T-welds of the high-strength low-alloyed steel was presented in [3]. Experimentally obtained values of mechanical characteristics in the elastic zone were higher than the related values calculated according to Eurocode 3 standard: Design of steel structures [4]. The authors concluded that the standard conservatively prescribes determination of the HSLA steel weld characteristics. Authors of [5] presented an experimental investigation of the influence of welding on strength of high performance steels. They concluded that welding significantly softened the heat affected zone in HSLA steel, with insignificant effects on the normal strength. The gas metal welding (GMA) of the HY-80 steels, with application of different welding parameters, was investigated in [6]. The executed test welds had values of the Charpy impact toughness similar to values in the weld metal and the HAZ; the measured values of hardness in the weld metal and the base metal were almost similar, while in the HAZ the values were higher. Authors in [7] presented an analysis of microstructural characteristics and mechanical properties of dissimilar joining welds of API 5L X60 ferritic HSLA steel and AISI 310S austenitic stainless steel (SZ \"Fiprom\", Jesenice, Slovenia). Experimentally obtained values led to the conclusion that for dissimilar welding between those two steels, the weld metal done by the ER2209 (SZ \"Fiprom\", Jesenice, Slovenia) duplex stainless steel filler metal provided the best mechanical properties. The multi-run welding of HSLA steel plates, executed by the manual metal arc (MMA) procedure, was investigated in [8]. Authors reported that it was relatively easy to fulfill requirements for the good mechanical strength of the weld metal, but that it was much more difficult to obtain good toughness and fatigue strength in the multi-run weld metal. Research of the influence of the welding parameters on the HSLA steel and on hardness and impact energy of samples, welded at related welding parameters, was presented in [9]. It was found that it was necessary to control and apply the optimal welding parameters, since even the slightest deviation from any of them could cause significant degradation in the quality of the welded joint. Authors in [10] presented a comparative study of the tensile and impact properties of the multi-pass SMAW Armox 500T steel joints (SSAB, Oxelosund, Sweden). The welds were executed with application of two different consumables: austenitic stainless steel and low hydrogen ferritic steel. The austenitic stainless steel consumable can be considered as a candidate welding consumable that can provide for good strain hardening and toughness of the welded joint, but the low hydrogen ferritic consumable is recommended for welded joints that require higher joint efficiency under tensile loading conditions. Research of the multi-pass welded joints of high-strength low-alloyed steel, done by underwater local cavity welding and underwater dry welding techniques, was reported in [11]. The authors obtained lower values of the yield strength and ultimate tensile strength on underwater local cavity welded specimens than on the underwater dry welding joint specimens. Still, the impact toughness was much higher for specimens of the latter technique. Authors of [12] implied that an important step in the design and fabrication of welded structures is selection of the welding process and the filler consumables. They applied three different welding techniques. Their experimental results showed that the higher level of residual stresses was registered in modified short arc welding and in flux cored arc welding than in shielded metal arc welding. They assumed that the higher levels of residual stresses were probably related to formation of bainite and Widmansatten ferrite in the weld metal and HAZ.