Determination of the rate of electrochemical dissolution of U10A steel under ECM conditions with a stationary cathode-tool

Abstract

Introduction. In blank production, when replacing hard alloys with tool steels, difficulties arise in shaping surfaces to ensure the required parameters of productivity, quality and accuracy, due to the presence of incomplete information for assigning electrochemical processing modes for this class of materials. This fact requires additional research to determine rational processing modes that provide the necessary technological parameters (productivity, dimensional accuracy and surface roughness). The purpose of the work is to conduct research to establish the patterns of electrochemical shaping of tool steels and determine the modes of the shaping process. The work investigated the features of anodic dissolution of U10A tool steel in an aqueous NaCl solution of 10 % concentration. The range of potential changes was from 0 to 8 V. Technological performance parameters were determined (current output for the main reaction and the rate of electrochemical dissolution at a voltage of 8 V and an electrolyte pressure of 0.1 MPa). Research methods. For polarization studies, a potentiodynamic research method was chosen. Technological experiments were carried out using the model of piercing holes with a stationary cathode-tool made of stainless steel without insulation. A circular cross-section with outer diameters of 0.908 mm and inner diameters of 0.603 mm was chosen as a cathode tool. Results and discussions: it is revealed that the electrochemical dissolution of U10A tool steel in a 10 % aqueous solution of NaCl is active in the studied potential range from 0 to 8 V. The technological experiments carried out made it possible to establish the dimensions of the resulting holes — an average diameter of 1.433 mm and a depth of 0.574 mm. The current efficiency was 70.83 %. Based on the analysis of the experimental data obtained, it is established that in order to ensure high productivity of the process of electrochemical forming of U10A steel in a solution of 10 % NaCl, the feed of the cathode tool should be 0.2232 mm/min, which corresponds to the rate of electrochemical dissolution under the studied forming conditions.