The macroscale simulation of remelting processes

Bertram, Lee A.; Schunk, Peter Randall; Kempka, S. N.; Spadafora, F.; Minisandram, Ramesh S.

doi:10.1007/s11837-998-0373-8

Cited by 33 publications

(32 citation statements)

References 9 publications

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“…The predicted ingot growth rate at the bottom is in the range of 2x10 -5 to 5x10 -5 m/sec, and the temperature gradient at the surface is high, nearly 5000 k/m and drops sharply towards the ingot center. These conditions would suggest columnar grains at the bottom and lateral surface, and equiaxed grains at towards the center (lower gradient) (20), which is consistent with the observed ingot macrograph (17).…”

Section: Var Modelingsupporting

confidence: 75%

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Recent Developments in Melting and Casting Technologies for Titanium Alloys

Fox¹,

Patel²,

Tripp³

et al. 2016

Proceedings of the 13th World Conference on Titanium

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Over the last twenty year melting and casting technologies for titanium alloys has continued to evolve and adapt in response to industry needs. In the primary titanium industry, efficient use of different raw materials has been enabled by the widespread adoption of cold hearth and skull melting and numerical simulation and advanced control methodologies have supported evolutionary changes in vacuum arc remelting (VAR) methods. The casting industry has also seen evolutionary changes and adapted plasma melting, VAR and induction skull melt methods to facilitate the successful introduction of gamma aluminides. With the widespread interest in powder technologies and additive manufacturing there are new melting and solidification challenges to be addressed. This paper will summarize recent changes in the melting capacity and technology in the industry and highlight some of the advances in numerical methods for the simulation of solidification and discuss some of the requirements and challenges to be addressed.

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Section: Var Modelingsupporting

confidence: 75%

“…In this section, a few results illustrating the capabilities of the model are presented using available processing data from a trial done in the late 90's (17). In this trial, a 0.914 m dia.…”

Section: Var Modelingmentioning

confidence: 99%

Recent Developments in Melting and Casting Technologies for Titanium Alloys

Fox¹,

Patel²,

Tripp³

et al. 2016

Proceedings of the 13th World Conference on Titanium

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show abstract

“…The electromagnetic field is obtained by solving Laplace's equation for the scalar potential. The governing equations and particulars regarding the boundary conditions have been published previously [7][8][9][10][11]. …”

Section: Brief Description Of the Modelmentioning

confidence: 99%

Modeling of Vacuum Arc Remelting of Alloy 718 Ingots

Patel¹,

Minisandram²,

Evans³

2004

Superalloys 2004 (Tenth International Symposium)

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Vacuum Arc Remelting (VAR) is typically the final melting process in the production of a wide range of alloys including superalloys, titanium, zirconium and specialty steels. During this process, a DC arc is struck under vacuum between a consumable electrode and a water-cooled copper crucible. The heat from the arc melts the electrode and molten metal droplets from the electrode solidify in the crucible to form an ingot. The purpose of VAR is to cast a sound, segregation free ingot. The soundness of the final structure and tendency for defect formation are determined by the pool profile and ingot solidification patterns during the process. These, in turn, depend on the melting parameters, which change as the ingot freezes. A carefully developed physics-based numerical model is useful in analyzing a priori the effect of melt parameters on the molten metal pool in the ingot. The purpose of this paper is to discuss the key features of such a model, and examine the effect of melting parameters on the pool profile. In addition, the effect of a molten metal pool perturbation during a power interruption and a melt rate cycle is examined for a 0.5m (20-inch) diameter ingot. Finally, the computed temperature distribution and flow field is used to predict the melting time for particles that fall into the molten pool and the likelihood of freckle formation in an alloy 718 VAR ingot.

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“…ESR is a suitable process for production of high quality heavy casting and forging due to its ability to improve the cleanness, macrostructure, the distribution and size of non-metallic inclusions. 1,2) Even if ESR is a good method for producing heavy ingot, but the larger the ingot is the higher the sensitive to segregation. Electrode configuration and operating parameters play an important role in ESR process, especially for manufacturing large casting and forging.…”

Section: Introductionmentioning

confidence: 99%

“…The larger the ingot is, the larger element prone to segregation is. 1,2) Moreover, the configuration of electrode has great influence on ingot quality. 13) Few literatures 15) about the impact of process parameters and electrode configuration on the remelting process have been found for large-scale ESR furnace now.…”

Section: Introductionmentioning

confidence: 99%

Simulation of Multi-electrode ESR Process for Manufacturing Large Ingot

et al. 2012

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Electroslag remelting process will be an important method for manufacturing heavy casing and forging due to its ability to improve the cleanness, macrostructure, microstructure, the distribution and size of non-metallic inclusions. In this paper, a finite element coupling model has been developed based on four electrodes configuration mode for manufacturing large ingot. Maxwell equation, Faraday's law, NavierStokes equation, heat transfer equation has been adopted in the model to analyze the current density, Joule-heat density, magnetic induction intensity and electromagnetic force and fluid flow distribution. The impact of slag depth, electrodes immersion depth and filling ratio on the molten pool depth has been analyzed. Results indicated that four electrodes with two sets of bifilar configuration are better than single phase with one electrode type. The molten pool is shallower for four electrodes than conventional single electrode mode, which is in favor of improving large ingot quality. The larger slag pool depth is the shallower the molten pool is. The depth of molten steel pool increases with the increasing of electrode immersion depth under the same slag depth condition. In addition, increasing filling ratio can reduce the depth of molten steel pool, but the filling ratio should be less than 0.6 according to area for general materials. Comparing to the single electrode mode four electrodes configuration mode is in favor of manufacturing large ingot.

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The macroscale simulation of remelting processes

Cited by 33 publications

References 9 publications

Recent Developments in Melting and Casting Technologies for Titanium Alloys

Recent Developments in Melting and Casting Technologies for Titanium Alloys

Modeling of Vacuum Arc Remelting of Alloy 718 Ingots

Simulation of Multi-electrode ESR Process for Manufacturing Large Ingot

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