A method of resistance welding electrodes manufacturing by combined casting and stamping

The present article describes the main functions of the resistance welding electrodes, as well as areas in which they are applied (engineering, automotive, aerospace industry, construction). With regard to the aerospace industry, the electrodes are used to obtain the compounds of an aircraft structural elements (connection of sheathing with framing members and connecting elements of the frame by resistance welding). Assessed is the complexity of the processes used in the manufacturing of resistance welding electrodes with a given set of physical-mechanical properties, as well as the complexity of managing the macro - and microstructure, strength and operational characteristics, changes in the structural and energetic state of the alloy. The method of introduction of alloying elements prepared in the melt by using tablets Cu-Cr is described. The technology of smelting and further pressing of the electrodes is tested. A subsequent heat treatment after forming the electrodes of resistance welding to achieve the highest level of physical and mechanical properties (hardness and conductivity) is defined. Investigated is the microstructure of the sample electrode in the optical microscope Carl Zeiss Axio Vision, showing a fairly uniform distribution of secondary phases in the bulk electrode. Energy dispersive analysis of samples of electrodes on a scanning electron microscope JEOL JSM-7001Fwas conducted, showing the approximate contents of the main elements in the alloy, as well as the distribution of chemical elements in characteristic radiation on the surface of a cone that has a considerable influence on the hardness and conductivity of the electrodes of resistance welding. The tests of the samples of the electrodes in resistance welding machine, MPTU-300, assessed their quality. As a result of practical tests of the optimal modes of contact welding of bar reinforcement cross of steel 35GS diameters 10+40 mm are chosen. The influence of nanostructured particles of chromium on the hardness, electrical conductivity and resistance of the electrodes of resistance welding is estimated. The dependences of the degree of wear of the electrodes from the number of welded points for various materials used in the manufacture of resistance welding electrodes are formed. Conclusions according to the results of the work are done.