Experimental Study of Surface Characteristic in Electrochemical Machining of 35CrMo Steel

Abstract

35CrMo steel is a widely used material in machinery equipment for the petroleum industry. With the improvement of exploring technology, some particular complex features cannot be achieved with traditional processing methods. However, electrochemical machining provides a potential solution to such problems, especially in the machining of the turbine blades of turbine drilling tools, in which the surface behavior of the workpiece is an important basis for judging the machining effect. To investigate the surface behavior of 35CrMo after electrochemical machining, the electrochemical machining experiment of 35CrMo steel was conducted by a self-made experimental system. Effects of the electrolyte type, concentration, and current density on surface quality were investigated in this study. The surface characteristics of 35CrMo steel were analyzed under different current densities in three different electrolytes-NaCl, NaClO 3 and NaNO 3-with different concentrations. Based on the obtained results, an optimum machining plan was obtained. The principle of the electrolysis reaction of 35CrMo steel in NaCl, NaClO 3 and NaNO 3 electrolytes were studied as well. Experimental results showed that the best surface quality of 35CrMo steel was achieved under an NaClO 3 electrolyte concentration of 200 g/L and current density of 30 A/cm 2. The results in this paper provide a theoretical basis for the effective machining of complex parts such as downhole turbine blades.

Microstructural and chemical surface and rim zone changes of ferrite‐perlite 42CrMo4 steel after electrochemical machining

“…However, the rough surface occurs only at the end of the electrolyte flow, Figure 2. On the contrary, for sodium nitrate electrolyte and similar steel to the one used in this work, a high and a low current density results in an increased surface roughness and a medium current density generates a shiny, reflective surface [15]. Therefore, a higher current density at the end of the electrolyte flow is assumed to cause the rough surface area.…”