DISSIMILAR HARDOX AND LOW-ALLOY STEEL IN EXCAVATOR STRUCTURES

In the structure of excavators and other transport vehicles, it is observed that there is an increasing necessity to weld elements from the Hardox steels. The paper verifies the possibility to obtain accurate DMW (dissimilar metal welds from totally different grades of Hardox 450 steel with S355J2 steel). The microstructure and mechanical tests of the obtained various welds were analysed. Argon-based shielding gases with micro nitrogen additions were used for MAG welding. Gas mixtures with micro nitrogen additions of up to even 2000 ppm and their use in welding are an absolute novelty. The purpose of the manuscript was to find the correct parameters of making dissimilar joints with such modern mixtures and to determine the most suitable mixture for welding Hardox steel and low-alloy steel for use in the automotive industry.