Search academic texts

Information × Registration Number 0212U005154, 0111U002485 , R & D reports Title To work out the prototype model of equipment for the mechanized underwater welding with the use of modulation of welding current and external electromagnetic field popup.stage_title Head Maksymov Sergii, Registration Date 26-03-2012 Organization E.O. Paton Electric Welding Institute popup.description2 The object of study - wet underwater flux cored wire arc welding. Purpose - development of prototype equipment for the realization of the possibility of effective control of the weld metal formation and its properties in underwater welding by using a modulated power supply current and the external electromagnetic field. Research methods - chemical and gas analysis, metallurgical studies, determination of mechanical properties using standard techniques, optical and scanning microscopy, X-ray fluorescence analysis, the processing of experimental data using personal computer equipment. It was determined that the most effective depth and the stiffness of the welding current mode modulation effect on the depth of penetration. The most intensive of its increase is observed with increasing current pulse - about 30%. The value of the weld reinforcement depends mainly on the duration of the pause and the depth of modulation at a constant average current. The influence on the weld width is negligible. It is established that the use of an external electromagnetic field in all modes leads to a decrease in reinforcement of weld. The effect of an external electromagnetic field depends on its parameters. To increase the joint width and depth of penetration of the magnitude of induction must be 10 mT and reversing the interval - 0.09 sec. It is established that the conditions of these experiments, the external electromagnetic field does not fully eliminate the porosity. However, its use has led to a sharp decrease in the number of pores in the weld metal. Thus, for B = 10 mT the total pore volume in the section joints is reduced relative to baseline in 5 times, and at B = 15 mT - more than 8 times, and their average size - from 13-15 microns to 3-4 and a -2.5 microns, respectively. This is due to a sharp decline in the number of large pores with a diameter exceeding 16 microns. With increasing induction increases the number of small pores, whose total volume is negligible. They, unlike the joints produced by welding to the standard technology, evenly spaced across the cross section of the joints, not just near the fusion line. Reversing the magnetic field leads to mixing of the liquid phase and inhibits fusion of gas bubbles formed in the large pores, as is the case for underwater welding without an external electromagnetic field. Developed a prototype of the equipment, which includes a switching power supply with digital control of welding process parameters, the control unit and the influence of external electromagnetic device pairing. An algorithm for control of the pulses of the magnetic field from the power source and their synchronization with the current pulses with different multiplicity is developed. The effective range of regimes in relation to the problem of controlling the geometrical parameters of weld metal is determined. It was established that for a given parameter of the current pulse to increase the joint width and depth of penetration the magnitude of induction must be 10 ... 15 mT and the reversing interval - 0.09 sec. Depending on the welding condition the joint width increases from 10 to 35%, and the depth of penetration - from 30 to 60%. The results can be used to create the technology of underwater pulsed-arc welding with a controlled geometrical parameters of weld metal and its properties. Product Description popup.authors Кражановський Денис Миколайович Прилипко Олена Олександрівна popup.nrat_date 2020-04-02 Close