Ahieieva M. Development of scientific and technological fundamentals of electric arc surfacing and welding with the control magnetic fields action

The purpose of the work is to increase the efficiency of the processes of the electric submerged arc surfacing and welding of butt joints by electrode wires with the external control magnetic fields action. The object of research - the processes of automatic electric submerged arc surfacing and welding with the external control magnetic fields action. The subject of research is the influence of the longitudinal and transverse magnetic fields parameters on electromagnetic processes in a drop of electrode metal and in liquid metal of a welding bath at electric submerged arc surfacing and welding with the external control magnetic fields action. Methods of research: metallographic, scanning electron microscopy, micro-X-ray spectral analysis; calculation methods: using the theory of vector magnetic potential, modeling of induction of a constant magnetic field by an electrostatic field; experimental studies: induction - universal Tesla meter 43205 with Hall sensor with a base of 0.9x0.9 mm, the electrode wire melting coefficient - by weighing, the welds strength - static tensile test, wear test and resistance to thermal fatigue of the surfaced layers at elevated temperatures. Calculations based on the theory of vector magnetic potential showed that the main influence on the induction value of the longitudinal magnetic field in the area of the electrode drop and the welding bath has the magnetic properties of the wire at the arc surfacing. The distribution of the induction components of the control magnetic field in the electrode drop area and the welding bath is established based on the analogy of electrostatic and magnetostatic fields and equations for determining the electrostatic field strength. For the first time, the optimal parameters of the control magnetic fields are stated, at which the melting coefficient of the wires increases and the liquid metal in the welding bath is effectively mixed, the structure of beads and welds is grinded and their service characteristics are increased. It is stated that the strengthening of the surfaces of the details of metallurgical equipment should be carried out by wire surfacing with an alternating longitudinal magnetic field action, which increases the resistance of the metal to the thermal fatigue by 2 times and reduces wear by friction (at temperature T = 600ºC) by 20-25%