The work describes the methods of the experiments and the results of the empirical data for the evaluation of process parameters of arc welding flux cored wire with the full material balance. The model is a three equation system. The first equation describes the interaction between average and partial transition coefficients; the second equation shows the transition of an element from the metal phase; the third one characterizes the reduction of an element from the slag phase. Are averaged and stiffness ratios of transition elements in deposited metal and weld metal. Flux-cored wire welding weld metal composition and its welding technological properties depend on melting bands and charge and interaction formed phases with each other and gas. The result of these processes is the formation of welding bath a certain mass and composition. Analysis of experimental data allowed us to find the relationship process indicators (ratios of transition elements) with technological parameters. Are obtained by regression equations. Comparing experimental and calculated data showed their good convergence, suggesting the possibility of applying the method of complete material balance for the transition coefficients of elements in arc welding flux cored wire. The data obtained allow to predict the composition of welded metal or weld metal with arbitrary parameters of the welding flux cored wire, as well as to assess the effectiveness of the whole. Similarly a more economical variant of electrode coating composition can be determined. For that the cost of different coating compositions should be calculated that give weld deposit with similar concentrations of alloying elements, that ensures the required operational characteristics and resource saving.