scholarly journals Influence of the Longitudinal Magnetic Field on the Formation of the Bead in Narrow Gap Gas Tungsten Arc Welding

Metals ◽  
2020 ◽  
Vol 10 (10) ◽  
pp. 1351 ◽  
Author(s):  
Xiaoxia Jian ◽  
Hebao Wu
Keyword(s):  
Magnetic Field ◽  
Arc Welding ◽  
Molten Pool ◽  
Longitudinal Magnetic Field ◽  
Side Wall ◽  
Experimental Results ◽  
Narrow Gap ◽  
Welding Arc ◽  
Maximum Value ◽  
Side Walls

The oscillation arc assisted by an extra alternating longitudinal magnetic field (LMF) in narrow gap tungsten arc welding is proved to be effective in avoiding welding defects due to insufficient fusion at the side walls in joining thick wall plates. The behavior of the welding arc and molten pool under the LMF is simulated to reveal the influence of the LMF on the formation of a uniform penetration weld bead. A unified mathematical model was developed for the narrow gap tungsten arc welding including the plasma arc, molten pool, electrode, and their interactions. Under the LMF, the whole welding arc is deflected and oscillates between the two side walls. When the magnetic-field strength is larger than 6 mT, the axis of the arc deflects to the side wall; the maximum value of heat flux at the bottom decreases by one-half, and the maximum value at the side wall is increased by a factor of ten. On the other hand, under the LMF, the forces acting on the molten pool are changed; the fluid flow pattern is helpful to increase the heat transferred to the side walls. The model is validated by experimental results. Both the percentage deviations of the simulation weld penetration at the side wall and at the bottom from the experimental results are lower than 10%.

scholarly journals Numerical Simulation of Arc and Metal Transfer in Arc Welding Based Additive Manufacturing Assisted by External Longitudinal Static Magnetic Field

2020 ◽  
Author(s):  
Xiangman Zhou ◽  
Lian Liu ◽  
Boyun Wang ◽  
Xingwang Bai ◽  
Haiou Zhang ◽  
...  
Keyword(s):  
Magnetic Field ◽  
Additive Manufacturing ◽  
Surface Quality ◽  
Molten Metal ◽  
Arc Welding ◽  
Molten Pool ◽  
Electromagnetic Stirring ◽  
Single Bead ◽  
Valley Area

Abstract The surface quality is one of important quality factors for arc welding based additive manufacturing (AWAM) parts. In this study, AWAM process assisted by an external longitudinal static magnetic field (ELSMF) is applied to improve surface quality of AWAM parts. In order to study the internal mechanism of AWAM process assisted by an external longitudinal magnetic field, a three-dimensional weak coupling model of the arc and metal transport is developed to simulate the arc, molten pool dynamic in AWAM assisted by ELSMF. The simulated results of single-bead deposition show that the ELSMF induces the asymmetrical tangential electromagnetic stirring in arc and molten pool, which can increase molten pool dynamics, drive the molten metal moving to the edge of the molten pool and reduce the temperature gradient. The simulated results of overlapping deposition show that the asymmetrical tangential electromagnetic stirring force can drive the molten metal moving to valley area between overlapping beads, which is beneficial to filling the valley area and improving the surface quality of the AWAM parts. The single-bead deposition experiment shows that the applying of ELSMF can reduce the height as well as increase the width of single weld bead. The multi-bead overlapping and the multi-layer multi-pass deposition experiments demonstrate that the external magnetic field can improve the surface quality of multi-layer part. The conclusions of the above study can provide the reference for AWAM process assisted by magnetic field.

scholarly journals Экспериментальное исследование влияния магнитного поля удлиненного соленоида на растяжение металлических кумулятивных струй

2020 ◽  
Vol 90 (4) ◽  
pp. 637
Author(s):  
С.В. Федоров ◽  
А.В. Бабкин ◽  
В.М. Маринин
Keyword(s):  
Magnetic Field ◽  
Experimental Study ◽  
Magnetic Induction ◽  
Characteristic Time ◽  
Longitudinal Magnetic Field ◽  
Free Flight ◽  
Steel Target ◽  
Maximum Value ◽  
The Magnetic Field ◽  
Field Influence

Results of the experimental study of the long solenoid longitudinal magnetic field influence on stretching of metal shaped-charge jets in the free flight are presented. Shaped charges with a diameter of 50 mm with copper conic liner were used in experiments. Parameters of the solenoid discharge circuit with the capacitive store of energy were such that the characteristic time moments of magnetic induction maximum achievement made about 100 μs. For the magnetic field parameters realized in experiments with the maximum value of an induction up to 10 T the small increase in depth of steel target penetration was recorded which wasn't exceeding 10 %. The possible reasons of big difference of the received results with the results of similar experiments are discussed.

scholarly journals Magneto-thermocapillary-buoyancy convection in a square cavity with partially active vertical walls

2019 ◽  
Vol 23 (6 Part A) ◽  
pp. 3433-3442
Author(s):  
Emtinene Lajnef ◽  
Walid Hassen ◽  
Lioua Kolsi ◽  
Abdullah Al-Rashed ◽  
Rajab Al-Sayegh ◽  
...  
Keyword(s):  
Magnetic Field ◽  
Surface Tension ◽  
Side Wall ◽  
Active Part ◽  
Buoyancy Convection ◽  
Side Walls ◽  
Vertical Walls ◽  
Higher Temperature ◽  
The Right ◽  
Volume Method

Effect of magnetic field on combined surface tension and buoyancy convection in an enclosure with partially active vertical walls is investigated numerically. The active part of the left side wall is at a higher temperature than the active part of the right side wall. The bottom and the inactive parts of the side walls are adiabatic and capillary forces occur at the top free surface. The governing equations are discretized by the finite volume method. The results are obtained for Pr = 0.054, 0 ? Ha ? 100, 0 ? Ma ? 10000, and 2.104 ? Gr ? 2.106. The flow structure and temperature field were presented by streamlines and isotherms respectively. The surface tension effect of is manifested by increasing Marangoni number. The application of magnetic field was found to control the flow and to oppose the capillary effects.

scholarly journals Magnetic Field Effects on 4G Positions in Shielded Metal Arc Welding Process

2020 ◽  
Vol 9 (3) ◽  
pp. 694-703 ◽  
Keyword(s):  
Magnetic Field ◽  
Arc Welding ◽  
Molten Pool ◽  
Low Carbon Steel ◽  
Welding Process ◽  
Butt Joint ◽  
Low Carbon ◽  
Magnetic Field Effects ◽  
Shielded Metal Arc Welding ◽  
Metal Arc Welding

With the advancement of welding techniques, Arc-welding is one of the most commonly and widely used welding technique for variety of purposes. The underside of welding to be performed makes the molten pool going downward because of gravity vector pulling affects the molten pool. The main purpose of this study is to study how the molten of electrode produced reduce on going downward and produce a good root fusion in overhead position of welding in single V-butt joint with the help of magnetic field on the workpiece. The study of magnet characteristic which includes thebehaviour of molten pool toward magnetic field, the macrostructure and microstructure and its strength should be carried out. Each magnet strength has their own characteristics that affects toward weldment on base metal.As a result, it can be concluded that having a magnetic field applies on base metal A36 low carbon steel may reduce the molten pool from going downward. The selection of a correct magnet strength and welding process may produce good and quality weldment especially in terms of its weld properties and geometry.

Numerical Simulation of MIG Welding Arc with Longitudinal Magnetic Field

2011 ◽  
Vol 704-705 ◽  
pp. 668-673 ◽  
Author(s):  
Qi Wei Wang ◽  
Sheng Zhu ◽  
Feng Liang Yin ◽  
Yuan Yuan Liang ◽  
Xiao Ming Wang
Keyword(s):  
Magnetic Field ◽  
Numerical Simulation ◽  
Current Density ◽  
Longitudinal Magnetic Field ◽  
Welding Process ◽  
Three Dimensions ◽  
Anode Surface ◽  
Mig Welding ◽  
Welding Arc ◽  
Arc Pressure

In the study three dimensions finite element mathematical model of MIG welding with longitudinal magnetic field was established. By ANSYS FEA software the temperature and other physical characteristics of the arc were obtained including the distributions of current density and arc pressure on the anode surface. The simulated results show that when the additional longitudinal magnetic field was introduced into welding process, the temperature of arc decreased remarkably and peak value of temperature changed from 16 950K to 13 700K at a welding current of 120A. Under the action of longitudinal magnetic field, on the one hand, heat flux density and current density at the anode surface decrease in the arc core and rise at the edge of arc, on the other hand, arc pressure decrease and arc potential increase. Keywords: Numerical simulation; MIG welding arc; magnetic field

Longitudinal magnetic field influence on depth of fusion in arc welding of butt joints

2014 ◽  
Vol 0 (4) ◽  
Author(s):  
Oleksandr D. Razmyshliaiev ◽  
Pavlo O. Vydmysh ◽  
Stanislav V. Yarmonov ◽  
Maryna V. Ahyeyeva
Keyword(s):  
Magnetic Field ◽  
Arc Welding ◽  
Longitudinal Magnetic Field ◽  
Butt Joints ◽  
Field Influence

Three-dimensional MHD duct flows with strong transverse magnetic fields. Part 2. Variable-area rectangular ducts with conducting sides

1971 ◽  
Vol 46 (4) ◽  
pp. 657-684 ◽  
Author(s):  
J. S. Walker ◽  
G. S. S. Ludford ◽  
J. C. R. Hunt
Keyword(s):  
Magnetic Field ◽  
Boundary Layers ◽  
Three Dimensional ◽  
Side Wall ◽  
Transverse Magnetic ◽  
Reverse Direction ◽  
Wall Boundary ◽  
Strong Transverse ◽  
Side Walls ◽  
The Magnetic Field

In this paper the general analysis, developed in part 1, of three-dimensional duct flows subject to a strong transverse magnetic field is used to examine the flow in diverging ducts of rectangular cross-section. It is found that, with the magnetic field parallel to one pair of the sides, the essential problem is the analysis of the boundary layers on these (side) walls. Assuming that they are highly conducting and that those perpendicular to the magnetic field are non-conducting, the flow is found to have some interesting properties: if the top and bottom walls diverge, the side walls remaining parallel, then an O(1) velocity overshoot occurs in the side-wall boundary layers; but if the top and bottom walls remain parallel, the side walls diverging, these boundary layers have conventional velocity profiles. The most interesting flows occur when both pairs of walls diverge, when it is found that large, 0(M½), velocities occur in the side-wall boundary layers, either in the direction of the mean flow or in the reverse direction, depending on the geometry of the duct and the external electric circuit!The mathematical analysis involves the solution of a formidable integral equation which, however, does have analytic solutions for some special types of duct.

Mechanism Analysis of Magnetic Control High-Speed Welding Undercuts Disappear

2013 ◽  
Vol 774-776 ◽  
pp. 1127-1131 ◽  
Author(s):  
Lin Lu ◽  
Yun Long Chang ◽  
Ying Min Li ◽  
Feng Gao
Keyword(s):  
Magnetic Field ◽  
Liquid Metal ◽  
Molten Pool ◽  
High Speed ◽  
Flow Direction ◽  
Internal Flow ◽  
Effective Diameter ◽  
Magnetic Control ◽  
Mechanism Analysis ◽  
Welding Arc

Direction of flow of the liquid metal in the weld pool have important implications for weld. The liquid metal to weld edges near the point of internal flow in molten pool and the undercut could emerge when the liquid metal was freezing, by contrast, is not prone to undercut. The external magnetic fields could change the distance of surface tension of liquid metal, which may lead to the change of flow direction of molten pool. Article compares the different magnetic field under the condition of weld cross section of the timing of the welding arc. Results show that magnetic arc anode spots, TIG welding arc anode spot diameter greater than when there is no magnetic field effectively effective diameter, which will help reduce the undercut.

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