A preliminary test of a novel molten metal filler welding process

Abstract Self-developed high speed tandem TIG welding equipment were adopted to manufacture titanium welded tubes with high efficiency and high quality. The joint made by this high efficient welding process met Chinese standard requirements. A coupled electrode, arc and weld pool numerical model was also developed to investigate temperature and velocity distributions, and energy propagation of this welding process. The numerical results showed that the Marangoni stress was much higher than the arc shear stress, and was mainly positive after leading and trailing arcs in the x and y directions, so the molten metal flowed backward on the top weld pool surface. Previous studies proposed that a “pull-push” flow pattern defined as a backward molten metal flow after the leading arc and a forward molten metal flow before the trailing arc existed on the top weld pool surface in tandem arc welding processes, while it was not observed in this case. The calculated arc efficiency of the high speed tandem TIG welding was about 79.8%.

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Tubes’ Rupture at Faulty Fusion of Welding Seam

Materials Science Forum ◽

10.4028/www.scientific.net/msf.946.868 ◽

2019 ◽

Vol 946 ◽

pp. 868-873

Author(s):

Vladimir N. Shinkin

Keyword(s):

Molten Metal ◽

Large Diameter ◽

Welding Process ◽

Gas Oil ◽

Welding Seam ◽

Slag Inclusions ◽

Micro Cracks ◽

Different Shapes ◽

Flux Layer ◽

Metallurgical Reactions

In the straight-seam tubes, the appearance of defects in the area of the welding seam welded under the flux layer and the seam geometry are closely related to the technology and metallurgy of welding process. Possible defects are the pores, incisions, slag inclusions and cracks. The pores can appear in different shapes, with different distribution and in different amounts during the solidification of welding seam. When molten metal solidifies, the gas bubbles can come to the surface or remain inside the metal. The incisions may occur due to the fact that the juncture is not completely filled. Such incisions, passing most often along the edge of welding seam, are explained by the discrepancy between the amount of metal deposited per unit of time and the volume of the juncture. The occurrence of the slag inclusions is determined by the metallurgical reactions between the slag and the drop, separating from the end of the electrode, as well as the bath of molten metal. The cracks differ depending on the size, the nature of location and the causes. There are the macro-cracks and micro-cracks, the hot and cold cracks. In this paper the critical in-tube pressure, at which the destruction of tube occurs at the partial faulty fusion of the tube’s welding seam, is obtained. The results can be used in the diagnosis of the causes of the destruction of the steel large-diameter tubes of the main gas-oil tube-lines.

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An analytical solution for transient temperature distribution in fillet arc welding including the effect of molten metal

Proceedings of the Institution of Mechanical Engineers Part B Journal of Engineering Manufacture ◽

10.1243/0954405971516086 ◽

1997 ◽

Vol 211 (1) ◽

pp. 63-72 ◽

Cited By ~ 6

Author(s):

S. K. Jeong ◽

H. S. Cho

Keyword(s):

Temperature Distribution ◽

Analytical Solution ◽

Molten Metal ◽

Arc Welding ◽

Finite Thickness ◽

Infinite Plate ◽

Welding Process ◽

Transient Temperature ◽

Fillet Weld ◽

Transient Temperature Distribution

This paper presents an analytical solution to predict the transient temperature distribution in fillet arc welding, including the effect of the molten metal generated from the electrode. The analytical solution is obtained by solving a transient three-dimensional heat conduction equation with convection boundary conditions on the surfaces of an infinite plate with finite thickness, and mapping an infinite plate on to the fillet weld geometry, including the molten metal with energy equation. The electric arc heat input on the fillet weld and on the infinite plate is assumed to have a travelling bivariate Gaussian distribution. To check the validity of the solution, flux cored arc (FCA) welding experiments were performed under various welding conditions. The actual isotherms of the weldment cross-sections at various distances from the arc start point are compared with those of the simulation result. As the result shows a good accuracy, this analytical solution can be used to predict the transient temperature distribution in the fillet weld of finite thickness under a moving bivariate Gaussian distributed heat source. The simplicity and short calculation time of the analytical solution provides the rationale for using the analytical solution to model the welding control systems or to obtain an optimization tool for welding process parameters.

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Direct observation and numerical simulation of molten metal and molten slag behavior in electroslag welding process

Welding in the World ◽

10.1007/s40194-020-00969-1 ◽

2020 ◽

Vol 64 (11) ◽

pp. 1897-1904

Author(s):

Y. Ogino ◽

S. Fukumoto ◽

S. Asai ◽

T. Tsuyama

Keyword(s):

Numerical Simulation ◽

Molten Metal ◽

Direct Observation ◽

Molten Slag ◽

Welding Process ◽

Electroslag Welding

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Effect of ultrasonic welding process parameters on hydrostatic pressure resistance of hybrid textiles for weather protection

Textile Research Journal ◽

10.1177/0040517520988124 ◽

2021 ◽

pp. 004051752098812

Author(s):

Muktar Seid Hussen ◽

Yordan Kostadinov Kyosev ◽

Kathrin Pietsch ◽

Stefan Rothe ◽

Abera Kechi

Keyword(s):

Hydrostatic Pressure ◽

Process Parameters ◽

Welding Process ◽

Preliminary Test ◽

Ultrasonic Welding ◽

Welding Parameters ◽

Hot Air ◽

Pressure Resistance ◽

Different Levels

In the research project presented in this paper, the effects of welding width, pressure force, power, and speed of ultrasonic welding parameters on hydrostatic pressure resistance were examined. A flexible and lightweight PVC-coated hybrid textile material with uniform thickness was used for weather protection purposes. Three main welding parameters at three different levels were selected based on the preliminary test results involving welding widths of 6 and 12 mm. A lapped type of seam was applied for ultrasonic welding and conventional joining techniques. A conventionally sewn zigzag seam was produced using three main factors at two different levels according to the application area. To avoid seam permeability, the conventional seam was sealed with tape by means of hot-air tape welding and subsequently investigated regarding its hydrostatic pressure resistance. The hydrostatic pressure resistance value of the conventional seam was then compared with ultrasonic weld seams of 6 and 12 mm welding width, and its parametric influence on the quality of the seam was analyzed. The result shows that the ultrasonic weld seam with a 12 mm welding width provided a higher hydrostatic pressure resistance than the 6 mm welding width and the conventionally sewn seam. Statistical analyses were also carried out to prove the significant effect of welding process parameters on hydrostatic pressure resistance, whereby the obtained results were statistically significant. A suitable nonlinear numerical model was also developed to predict the hydrostatic pressure resistance.

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Influence of shielding gas composition on molten metal flow behavior during plasma keyhole arc welding process

Journal of Manufacturing Processes ◽

10.1016/j.jmapro.2020.03.031 ◽

2020 ◽

Vol 53 ◽

pp. 431-437 ◽

Cited By ~ 4

Author(s):

Anh Van Nguyen ◽

Shinichi Tashiro ◽

Manh Huu Ngo ◽

Anh Hoang Le ◽

Hanh Van Bui ◽

...

Keyword(s):

Molten Metal ◽

Arc Welding ◽

Flow Behavior ◽

Metal Flow ◽

Welding Process ◽

Gas Composition ◽

Shielding Gas ◽

Arc Welding Process ◽

Molten Metal Flow

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Effects of bottom plate in friction stir welding of AA6061-T6

Metallurgical Research & Technology ◽

10.1051/metal/2020087 ◽

2020 ◽

Vol 118 (1) ◽

pp. 108

Author(s):

M.A. Vinayagamoorthi ◽

M. Prince ◽

S. Balasubramanian

Keyword(s):

Mechanical Properties ◽

Axial Load ◽

Weld Zone ◽

Welding Process ◽

Bottom Plate ◽

Welding Parameters ◽

Nugget Zone ◽

Friction Stir ◽

Weld Joints ◽

Fine Grain

The effects of 40 mm width bottom plates on the microstructural modifications and the mechanical properties of a 6 mm thick FSW AA6061-T6 joint have been investigated. The bottom plates are placed partially at the weld zone to absorb and dissipate heat during the welding process. An axial load of 5 to 7 kN, a rotational speed of 500 rpm, and a welding speed of 50 mm/min are employed as welding parameters. The size of the nugget zone (NZ) and heat-affected zone (HAZ) in the weld joints obtained from AISI 1040 steel bottom plate is more significant than that of weld joints obtained using copper bottom plate due to lower thermal conductivity of steel. Also, the weld joints obtained using copper bottom plate have fine grain microstructure due to the dynamic recrystallization. The friction stir welded joints obtained with copper bottom plate have exhibited higher ductility of 8.9% and higher tensile strength of 172 MPa as compared to the joints obtained using a steel bottom plate.

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