Procedure for replacing the material for manufacturing the responsible welded structure

Abstract

Due to difficult pandemic situation with COVID-19 decease, as well as due to current geopolitical circumstances in the world, we are facing the shortage of steel and therefore the impossibility of delivering the contracted products within the agreed deadlines. It is thus necessary to find suitable steel for replacement. This paper describes in detail the procedure for selecting one such steel for substituting the deficit steel 25CrMo4 for the purposes of producing a responsible welded assembly. Prior to applying the newly selected steel, it was necessary to perform the following tests: analyze the chemical composition and mechanical properties, evaluate the weldability, determine the most important mechanical properties, as well as prescribe the optimal welding and heat treatment technologies, so that the quality of the responsible welded structure would meet all the requirements, as the structure made of originally used steel. After careful analysis by authors, steel 42CrMo4 was taken into consideration. For this steel, all the mentioned, as well as some additional tests were conducted and the appropriate welding technology for a highly responsible welded structure was prescribed. To verify the selected technology, appropriate tests were conducted, the results of which are presented in this paper. Based on the analysis of the obtained results, it was concluded that the 25CrMo4 steel can be replaced with the 42CrMo4 steel, however, with the mandatory application of appropriate supplementary measures.