scholarly journals Mechanism to Reduce the Porosity during Argon Arc Welding of Aluminum Alloys by Changing the Arc Angle

Metals ◽  
2020 ◽  
Vol 10 (9) ◽  
pp. 1121
Author(s):  
Senchang Chen ◽  
Yanhui Chi ◽  
Ping Zhang ◽  
Yusheng Shi
Keyword(s):  
Molten Metal ◽  
Molten Pool ◽  
Metal Flow ◽  
Vertical Component ◽  
Far Infrared ◽  
Test Results ◽  
Porosity Reduction ◽  
Industrial Computed Tomography ◽  
Average Size ◽  
Torch Angle

A mechanism to reduce the porosity by changing the arc angle during aluminum alloy welding was studied. Industrial computed tomography was used to scan the welds with different arc angles, and the scanned model was processed by a specific software package to obtain the digital size and position of weld pores. The forces acting on the pores in the molten pool explained the test results that the number of pores decreases and the average size increases. As the inclination angle of the arc increased, the vertical component that prevented the bubble from rising decreased, and the horizontal component that pushed the molten metal flow and promoted the nucleation and growth of the bubbles increased. A horizontal movement during the droplet transition as the arc inclination was produced, which was conducive to the growth and overflow of bubbles. The theoretical analysis and temperature field measured by a far-infrared with different torch angle showed that when the arc was tilted from 0, the shape of the molten pool changed from the circle to the ellipse. The long axis of the ellipse increased as the bevel angle of the arc increased. This showed that the molten metal existed a longer time for the bubbles to escape from the molten pool when the angle of the arc increased. The paper provides fundamental insights into a mechanism for porosity reduction during the welding of Al alloys.

Automatic Control of Molten Metal Flow for Improving Casting Performance

2011 ◽  
Vol 693 ◽  
pp. 179-184
Author(s):  
Thomas Jarlsmark ◽  
Jan Strömbeck ◽  
Mikael Terner ◽  
Jerry Wilkins
Keyword(s):  
Molten Metal ◽  
Metal Flow ◽  
Casting Process ◽  
Direct Chill ◽  
Level Control ◽  
Level Measurement ◽  
Cost Efficient ◽  
Molten Metal Flow ◽  
Automatic Level ◽  
Rolling Ingot

The ways to gain better quality and higher casting performance is an urgent topic among aluminium producers today. This issue is also often on the agenda at conferences like this and the subjects and technologies to achieve this varies. Controlling the molten metal flow by maintaining predefined levels or level patterns is one of many powerful tools to reach this goal. Precimeter Control specializes in applications for non-ferrous molten metal level measurement and molten metal flow control. By integration, or retrofitting, any new or existing casting line can easily be automatically controlled and gain improved casting performance in a cost efficient way. This paper will focus on the main benefits from automatic level control and how some plants have achieved improvements in their casting process of DC (Direct Chill) slab (or rolling ingot) casting after implementing such technology.

scholarly journals Computational investigation of thermal behavior and molten metal flow with moving laser heat source for selective laser melting process

2021 ◽  
Vol 24 ◽  
pp. 100860
Author(s):  
Patiparn Ninpetch ◽  
Pruet Kowitwarangkul ◽  
Sitthipong Mahathanabodee ◽  
Prasert Chalermkarnnon ◽  
Phadungsak Rattanadecho
Keyword(s):  
Heat Source ◽  
Thermal Behavior ◽  
Selective Laser Melting ◽  
Molten Metal ◽  
Metal Flow ◽  
Melting Process ◽  
Computational Investigation ◽  
Laser Melting ◽  
Laser Heat Source ◽  
Molten Metal Flow

scholarly journals Molten metal flow through multiple gates in the runner of die casting.

1986 ◽  
Vol 36 (9) ◽  
pp. 577-581
Author(s):  
Yasushi IWATA ◽  
Yoshiaki YAMAMOTO ◽  
Motoshi NAKAMURA ◽  
Haruo SUZUKI ◽  
Hiroshi SAWADA ◽  
...  
Keyword(s):  
Molten Metal ◽  
Die Casting ◽  
Metal Flow ◽  
Flow Through ◽  
Molten Metal Flow

Numerical Simulation of Three-Dimensional Molten Pool Temperature Field and Flow Field for Laser Melt Injection Based on Fluent

2012 ◽  
Vol 538-541 ◽  
pp. 1837-1842 ◽  
Author(s):  
Long Zhi Zhao ◽  
Zi Wang ◽  
Xin Yan Jiang ◽  
Jian Zhang ◽  
Ming Juan Zhao
Keyword(s):  
Temperature Field ◽  
Liquid Metal ◽  
Molten Pool ◽  
Metal Flow ◽  
Three Dimensional ◽  
Transient Temperature ◽  
Transient Temperature Field ◽  
Liquid Metal Flow ◽  
Fluent Software ◽  
Thermo Physical Properties

According to the characteristics of laser melt injection, a numerical model for a simplified 3D transient temperature field in molten pool was established using FLUENT software in this paper. In the model, many factors were considered such as liquid metal turbulence, latent heat of phase transformation and material thermo physical properties depending on temperature. The results show that the model can be developed well by FLUENT software. And the results also show that the driving force of the liquid metal flow mechanism.

scholarly journals Multiple dust shells around Herbig Ae/Be stars

1987 ◽  
Vol 122 ◽  
pp. 99-100
Author(s):  
P.S. Thé ◽  
D. N. Dawanas
Keyword(s):  
Main Sequence ◽  
Near Infrared ◽  
Spectral Energy Distribution ◽  
Far Infrared ◽  
Central Star ◽  
Spectral Energy ◽  
Be Stars ◽  
Intermediate Mass ◽  
Dust Shells ◽  
Average Size

Intermediate mass (2 < M/M⊙ < 9) pre-main sequence objects, also named Herbig Ae/Be stars, are known to have excess radiation in the near-infrared. From IRAS o bservations it turns out without doubt (quality 3, high S/N radio), that these objects are very strong far-infrared emitters at 12, 25, 60 and often also at 100 μm. The spectral energy distribution, depicted in Fig. 1 for intermediate mass pre-main sequence stars, show clearly this large excess. From the difference curves it is apparent that this excess radiation is most probably caused by several dust shells. Using very simplified methods it is possible to derive the average temperature of the dust shells (see Thé, Wesselius, Tjin A Djie and Steenman, 1986). If the chemical composition of the mixture of the dust grains and their average size are assumed it is also possible to estimate other characteristics like the distance from the central star and the mass of the dust shells (see Thé, Hageman, Westerlund, Tjin A Djie, 1985).

scholarly journals Development of a Kármán Vortex Probe for Measuring the Velocity of Molten Metal Flow

1994 ◽  
Vol 35 (10) ◽  
pp. 716-721 ◽  
Author(s):  
Manabu Iguchi ◽  
Masamichi Takeuchi ◽  
Hirotoshi Kawabata ◽  
Kiyoshi Ebina ◽  
Zen-ichiro Morita
Keyword(s):  
Molten Metal ◽  
Metal Flow ◽  
Molten Metal Flow

scholarly journals Model of Infiltration of Spent Automotive Catalysts by Molten Metal in Process of Platinum Metals Recovery

2013 ◽  
Vol 2013 ◽  
pp. 1-7 ◽  
Author(s):  
Agnieszka Fornalczyk ◽  
Slawomir Golak ◽  
Mariola Saternus
Keyword(s):  
Electromagnetic Field ◽  
Molten Metal ◽  
Metal Flow ◽  
Precious Metals ◽  
Automotive Catalysts ◽  
Catalyst Carrier ◽  
Metals Recovery ◽  
Spent Catalysts ◽  
Hydrodynamic Field ◽  
The Impact

This paper presents the model for the washing-out process of precious metals from spent catalysts by the use of molten lead in which the metal flow is caused by the rotating electromagnetic field and the Lorentz force. The model includes the coupling of the electromagnetic field with the hydrodynamic field, the flow of metal through anisotropic and porous structure of the catalyst, and the movement of the phase boundary (air-metal) during infiltration of the catalyst carrier by the molten metal. The developed model enabled analysis of the impact of spacing between the catalysts and the supply current on the degree of catalyst infiltration by the molten metal. The results of calculations carried out on the basis of the model were verified experimentally.

A Numerical Study of a Molten Aluminum for Investment Casting of 3D Cellular Metals

2013 ◽  
Author(s):  
Jiwon Mun ◽  
Jaehyung Ju ◽  
Byoung-Gwan Yun ◽  
Byung-Moon Chang ◽  
Doo-Man Kim
Keyword(s):  
Liquid Metal ◽  
Velocity Profile ◽  
Molten Metal ◽  
Investment Casting ◽  
Metal Flow ◽  
Temperature Dependent ◽  
Temperature Dependent Viscosity ◽  
Dependent Viscosity ◽  
Analytical Approaches ◽  
Numerical Approaches

Investment casting processes are influenced by a variety of parameters. Many researches considering viscosity as a constant have been conducted up to this point. In particular, however, viscosity with temperature change has not been much accounted for solidification and heat transfer simulation of molten metal in the investment casting process. In addition, analysis of behavior of metal flow as well as air gap problems for complex network structures have not been investigated much. The aim of this study is to build transient metal flow and velocity profile models considering temperature dependent viscosity in investment casting processes of cellular structures. In this study, a Computational Fluid Dynamics (CFD) modeling tool was used for metal flow and velocity profile in investment casting processing using User Defined Function (UDF) for temperature dependent viscosity. The results of the metal flow and velocity profile inside of the simple cylindrical geometry are represented. It is shown that for the validation of the numerical simulation, the velocity profile between analytical and numerical approaches showed very good agreement. Analytical approaches showed that velocity was reduced with the increase in viscosity, which is applied as a function of temperature. In particular, rapid decreasing in velocity was shown from under the melting temperature of the molten metal. There was no movement on metal flow at the room temperature. Numerical approaches showed that the liquid metal began to be solidified from the wall surface inside of the mold. For the same simulation time, it was shown that the metal flow in a cylinder that has 1mm diameter showed better fluidity rather than that of the cylinder that has 2mm diameter due to the increase in adhesion between liquid metal and the surface of the mold and surface tension between molten metal and air. The effective diameter by solidification is decreased with the time change.

scholarly journals Difference of the size of average crown width first molar and second molar mandible of the Pawon Man with modern man

2012 ◽  
Vol 24 (3) ◽  
Author(s):  
Taufik Senjaya ◽  
Fahmi Oscandar ◽  
Lutfi Yondri
Keyword(s):  
Food Processing ◽  
Cone Beam ◽  
Food Technology ◽  
Test Results ◽  
Second Molar ◽  
Crown Width ◽  
Measurement Results ◽  
The Difference ◽  
Average Size ◽  
Descriptive Method

Introduction: Pawon Man is prehistoric human who was expected life about 9525-5660 BC and have lived in a Cave Pawon located in Mountain Masigit Village, District Cipatat, Bandung Regency. The purpose of this research to analyzed the difference size of average crown width first molar and second molar mandible Pawon Man with Modern Man. Methods: The research used a descriptive method, so that from 4 archives radiograph Pawon man, can be obtained 14 samples radiographs Cone Beam Computed Tomography first tooth molars and second molars mandible. The research conducted on Ez Implant-3D program using a digital ruler, measurement results then recorded in tabular form, then statistically analyzed using independent two-sample t test. Results: The average size of widht crown first tooth molars and second molars mandible were larger for Pawon Man teeth than Modern Man. Conclusion: The average size of widht crown first tooth molars and second molars mandible were larger for Pawon Man teeth, because Pawon Man eating hard food and rough textured with simple food processing, with transition of culture has changed the dietary and food technology, so the shape of the big teeth are no longer needed.

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