Effect of Pouring Temperature and Water Cooling on the Thixotropic Semi-solid Microstructure of A319 Aluminium Cast Alloy

El-Mahallawi, I.; Mahmoud, T. S.; Gaafer, A. M.; Mahmoud, Fouad H.

doi:10.1590/1516-1439.304114

Cited by 19 publications

(7 citation statements)

References 15 publications

(19 reference statements)

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“…Fluidity, in turn, depends upon many factors related to the molten metal, mould, metal/mould interface etc. 40,41 , making synchronization a challenge when manual pouring is used. Furthermore, heat transfer between ingot, mould and environment should be sufficient to prevent excessive grain growth and allow a sufficiently thick, solid shell to form and the mushy zone (where solid and liquid coexist in the solidifying ingot) to develop a substantial coherent volume, i.e., a solid matrix substantial enough to bear the extraction load [42][43][44] .…”

Section: Methodsmentioning

confidence: 99%

A Continuous Casting Device with Electromagnetic Stirring for Production of SSM Feedstock Using Al-Si Alloys

2021

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This work describes the design, construction and testing of a continuous casting device coupled to an electromagnetic stirring system for the production of thixoforming feedstock using Al-Si alloys. The following processing and construction parameters were tested: pouring temperature (660-800 °C), mould cavity roughness (Ra = 0.17-1.06 µm), casting speed (2-4 mm/s), use of a combined (primary and secondary) cooling system and the intensity and radial penetration of electromagnetic stirring (0, 1500 and 3000 W stator power). The macro-appearance of the ingots and the longitudinal and radial microstructural parameters were then evaluated. The results indicate that the surface finish of the mould cavity was an important construction parameter as it had a strong influence on heat transfer and, consequently, feed speed; use of a secondary cooling system for the mould allowed greater grain refinement and microstructural homogeneity to be achieved for all the conditions tested; optimal electromagnetic stirring power was 1500 W (EMF max = 22 Gauss); this resulted in a grain size-todendritic arm spacing ratio of close to 1, which is suitable for subsequent SSM processing.

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Section: Methodsmentioning

confidence: 99%

A Continuous Casting Device with Electromagnetic Stirring for Production of SSM Feedstock Using Al-Si Alloys

2021

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“…The micrographs show also α-Al grains for AA7075 is smaller than α-Al grains for A356. Tables (3,4) list the values of the grain sizes of A356 and AA7075 of the primary α-Al grains at axial and radial locations of the A356 and AA7075 feedstock produced by various pouring temperatures. Generally, the feedstock exhibited lower average grain size at the bottom of feedstock when compared with the middle and the top of the feedstock.…”

Section: 3microstructural Examinationsmentioning

confidence: 99%

“…Semi-solid processing (SSP) as a modern and advanced technology has been used in the manufacturing of engineering components [1]. Semi-solid metal processing enables us to manufacture complicated shape components with near-net wall, good mechanical properties and high dimension tolerance accuracy [2][3][4]. SSP has some advantages in comparison with conventional casting, such as decreasing the macrosegregation and solidification shrinkage and reducing forming temperature [5][6][7].…”

Section: Introductionmentioning

confidence: 99%

“…Because of the absence of the dendritic solid phase in the semi-solid state, the alloy is easily shaped. The nondendritic microstructure contains solid phase globules suspended in the liquid phase [4,8]. Industrial thixocasting of aluminium alloys is based on the benefits in comparison with casting processes, which have led to various serial production methods in spite of the additional costs for primary material and investment costs for heating equipment.…”

Section: Introductionmentioning

confidence: 99%

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Microstructure of A356 and Aa7075 Poured by Cooling Slope Casting at Different Pouring Temperatures.

Mohamed

2018

Journal of Al-Azhar University Engineering Sector

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Semisolid metal processing (SSMP) is a technology that involves the formation of metal alloys between solidus and liquidus temperatures. For the step to operate successfully, the microstructure of the starting material consist of solid near-globular grains surrounded by a liquid matrix and a wide solidus-to-liquidus transition area. Thus the process of SSMP relies on the thixotropic behavior of alloys with a spheroidal rather than a dendritic microstructure in semisolid state. Now, this process is industrially successful, generating a variety of products with high quality parts in many industrial sectors. This technology promises advantages over conventional metal forming technologies. Aluminum alloys are among the most prominent and well-known materials used in the mechanical construction and automotive industries. In this investigation, effect of pouring temperature and the type of the materials poured was studied. Molten A356 and AA7075 alloys with temperatures of 620 °C, 640 °C and 660 °C was poured on the surface of inclined plates then casting in the mould.

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“…The process involves two stages, namely, reheating and forming 1 . Reheating the billet in a semisolid state is a particularly crucial stage in thixoforming and is mainly achieved by induction heating to obtain a uniform nondendritic microstructure [2][3][4][5][6][7][8][9] . This inductive heating system is non-contact, clean, precise and rapid in heating 7,8 .…”

Section: Introductionmentioning

confidence: 99%

High-Frequency Induction Heating of Al-Si-Cu-Mg aluminum alloy in Thixoforming

2019

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Thixoforming is the process of shaping near net shape metal components in a semisolid state. The process consists of preparing feedstock, reheating and shaping. Reheating the billet is the most critical step in thixoforming. Induction heating requires precise temperature control to obtain globular microstructure and prevent process defects, such as insufficient heating, overheating, and electromagnetic end effect and elephant foot phenomena. Moreover, inductive heating parameters are investigated to improve the quality of thixoforming. This study investigates applied coil current and optimal coil geometry and design (i.e. height, diameter and coil turn) in high-frequency induction heating numerically and experimentally. Simulation results combined with an approximation approach method are verified via a reheating experiment. The proposed method validated via an experiment can be a practical tool for predicting temperature distribution and reheating time required for thixoforming.

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Effect of Pouring Temperature and Water Cooling on the Thixotropic Semi-solid Microstructure of A319 Aluminium Cast Alloy

Cited by 19 publications

References 15 publications

A Continuous Casting Device with Electromagnetic Stirring for Production of SSM Feedstock Using Al-Si Alloys

A Continuous Casting Device with Electromagnetic Stirring for Production of SSM Feedstock Using Al-Si Alloys

Microstructure of A356 and Aa7075 Poured by Cooling Slope Casting at Different Pouring Temperatures.

High-Frequency Induction Heating of Al-Si-Cu-Mg aluminum alloy in Thixoforming

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