The use of electromagnetic stirring for increasing the quality of electroslag joints

Chernysh, V. P.; Кузнецов, В. Д.; Kazakov, N. K.; Briskman, A. N.; Gladyshko, V. S.

doi:10.1007/bf01157957

Cited by 7 publications

(7 citation statements)

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“…Магнітне поле зварювального струму та положення дуги в просторі визначають магнітогідродинамічні явища в зварювальній ванні та формування швів. Але закономірності регулювання енергетичної характеристики дуги, магнітогідродинамічних явищ і підвищення ударної в'язкості зварних з'єднань досліджено недостатньо [1][2][3][4][5][6][7][8][9][10][11].…”

Section: вісник приазовського державного технічного університету 2022рunclassified

Welding arc energy characteristic regulation

Shchetinin¹,

Shchetinina²

2022

ПДТУ

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When welding pipes, due to the concentration of magnetic field lines in a ferromagnetic pipe with high magnetic permeability, the welding current magnetic field increases, magnetic blow, under. by the action of electromagnetic force, the arc length increases up to a break, the current and voltage on the arc fluctuate significantly, the seam dimensions change from a point to a large width, the process stability is disturbed, the welds formation and the welded joints impact toughness is reduced. Based on the study of the arc energy characteristics, according to which the voltage on the arc increases with increasing arc length, it was found that the arc moves along the tape end at a speed of 3.3 m/s, the electrode shape affects the welding arc. energy and voltage characteristics. In this case, the sum of near-electrode voltage drops depends on the work function of electrons from the cathode surface of the flux components and does not depend on the electrode shape, which confirms the main role of field emission in the arc and the arc concentration below. pinch-effect. To increase the welded joints impact toughness, it is necessary to reduce energy, heat input, crystal lattice microdistortions, microstresses, dislocation density, welding stresses, reduce the weld width, heat-affected zone, the deposited metal amount and refine the microstructure. An effective way to reduce energy is to increase the welding speed, which reduces the heat input, and reduce the arc length, arc voltage, which leads to an increase in the arc rotation speed, pinch effect, arc concentration and energy, heat input efficiency, reduce welding stresses, increase the crystallization rate, the microstructure refinement, the interatomic distance reduction and interatomic bonds increase. A process for one-sided high-speed welding of pipes for gas and oil pipelines with a low-energy composite electrode, which, due to low arc voltage, arc concentration, stability, energy reduction, heat input, welding stresses, microstructure refinement, interatomic distance reduction and interatomic bonds increase, provides an increase in the welded joints impact toughness 2-2.5 times has been developed. Minimum energy – maximum welded joints impact toughness

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Section: вісник приазовського державного технічного університету 2022рunclassified

Welding arc energy characteristic regulation

Shchetinin¹,

Shchetinina²

2022

ПДТУ

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“…The use of controlling effects of longitudinal magnetic fields, or transverse magnetic fields in arc welding increases the productivity of the process, refines the structure of welds, and improves the service characteristics of welded products [9][10][11][12]. In [12] it is shown that there are many hypotheses about the mechanism of weld structure refinement in welding with controlling magnetic fields.…”

Section: Introductionmentioning

confidence: 99%

To the mechanism of influence of an alternating electromagnetic field on crystallization process of oxide refractory melts

Abdrakhmanov,

Yegzekova,

Kaliyev

2023

Vib. proced.

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Electromagnetic effect during crystallization of melts of various materials (metallic, salt, slag, oxide) is able to change significantly its macro- and microstructure and improve its physical and technical characteristics. There are many hypotheses about the mechanism of electromagnetic field effect on the structure of various metals. There are limited studies on the effect of electric, magnetic and temperature fields on the crystallization of non-metallic crystals in complex halide and oxide systems. The available works on this topic are fragmentary and are aimed only at solving the utilitarian problem of obtaining crystals. No studies on the mechanism of electromagnetic field effect during high-temperature crystallization of oxide refractory melts on its final characteristics have been found in the known scientific literature. In this paper, for the first time, based on the analysis of known hypotheses, the new study of mineral composition, structure-sensitive characteristics and structural units of melts, new hypothesis about the mechanism of effect of alternating electromagnetic field on the structure of oxide refractory materials crystallizing from melts on the example of forsterite, forsterite-chromite and corundum refractories has been put forward. The most probable effect mechanism of an alternating electromagnetic field on the structure of crystallizing oxide refractory castings is its periodically orienting and intensifying migration of the structural units of the melt action.

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“…Positive effect of the magnetic field on the properties and metal structure at welding many steels is known. Weld pool stirring has a significantl impact on the process of molten metal solidification, gas exchange reactions, and weld metal structure formation [1][2][3][4]. Studies have confirmed the effectiveness of using external electromagnetic impact (EEI) in underwater welding to improve the weld metal mechanical properties.…”

Section: Introductionmentioning

confidence: 99%

Analytical Evaluation of Strengthening, Local Internal Stresses and Microderformations in Welded Joint Metal during Wet Underwater Welding

Maksimov

Berdnikova

Prilipko

2021

DDF

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Analysis of structural factor influence on local internal stresses and zones of deformation localization in upper and lower bainite structures in welded joints of low-alloy steel at wet underwater welding was performed. It is established that when welding joints under the water and applying an external electromagnetic field in the metal of the heat-affected zone (HAZ), a finer-grained substructure is formed with a general decrease in the dislocations density and with their uniform distribution. Estimates of the local internal stresses level considering the dislocation density distribution in the structural zones of their localization show that their maximum level is formed in the metal of the HAZ overheating region at welding without the external electromagnetic field along the upper bainite laths boundaries. The upper bainite structure is characterized by forming localized deformation zones, where the most significant dislocation density gradients are observed. This can lower the crack resistance of welded joints. Low values of local internal stresses are characteristic of welded joints obtained in the modes applying an external electromagnetic field. This is facilitated by the overall decrease in the dislocation density and their uniform distribution in the lower bainite structural components, which provides high crack resistance of welded joints.

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The use of electromagnetic stirring for increasing the quality of electroslag joints

Cited by 7 publications

References 0 publications

Welding arc energy characteristic regulation

Welding arc energy characteristic regulation

To the mechanism of influence of an alternating electromagnetic field on crystallization process of oxide refractory melts

Analytical Evaluation of Strengthening, Local Internal Stresses and Microderformations in Welded Joint Metal during Wet Underwater Welding

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