scholarly journals Direct Chill Casting and Extrusion of AA6111 Aluminum Alloy Formulated from Taint Tabor Scrap

Materials ◽  
2020 ◽  
Vol 13 (24) ◽  
pp. 5740
Author(s):  
Kawther Al-Helal ◽  
Jayesh B. Patel ◽  
Geoff M. Scamans ◽  
Zhongyun Fan
Keyword(s):  
Extrusion Process ◽  
Direct Chill ◽  
Direct Chill Casting ◽  
Grain Structure ◽  
Chill Casting ◽  
Automotive Body ◽  
Processing Cost ◽  
Scrap Aluminum ◽  
Co Addition ◽  
Equiaxed Grains

AA6111 aluminum automotive body-sheet alloy has been formulated from 100% Taint Tabor scrap aluminum. Direct chill casting with and without high shear melt conditioning (HSMC) was used to produce the AA6111 alloy billets. Both homogenized and non-homogenized billets were extruded into sheets. The optical micrographs of the melt conditioned direct chill (MC-DC) samples showed refined equiaxed grains in comparison to direct chill (DC) cast and direct chill grain refined (DC-GR) samples. Optical metallography showed extensive peripheral coarse grain (PCG) for the DC, DC-GR and MC-DC planks extruded from the homogenized standard AA6111 billets while planks extruded from modified AA6111 billets (with recrystallization inhibitors) showed thin PCG band. The co-addition of recrystallization inhibitors Mn, Zr, and Cr with elimination of the billet homogenization step had a favorable impact on the microstructure of the AA6111 alloy following the extrusion process where a fibrous grain structure was retained across the whole section of the planks. The mechanical properties of as-cast planks extruded from non-homogenized billets were similar to those extruded from homogenized billets. Eliminating the homogenization heat treatment step prior to extrusion has important ramifications in terms of processing cost reduction.

Direct Chill Casting of Aluminum Alloys: Modeling and Experiments on Industrial Scale Ingots

2001 ◽  
Author(s):  
Christopher J. Vreeman ◽  
J. David Schloz ◽  
Matthew John M. Krane
Keyword(s):  
Casting Process ◽  
Direct Chill ◽  
Solid Particles ◽  
Direct Chill Casting ◽  
Grain Structure ◽  
Temperature Fields ◽  
Industrial Scale ◽  
Grain Refiner ◽  
Chill Casting ◽  
Continuum Mixture Model

Abstract A continuum mixture model of the direct chill casting process is compared to experimental results from industrial scale aluminum billets. The model, which includes the transport of free-floating solid particles, can simulate the effect of a grain refiner on macrosegregation and fluid flow. It is applied to an Al - 6 wt% Cu alloy and the effect of grain refiner on macrosegregation, sump profile, and temperature fields are presented. Two 45 cm diameter billets were cast under production conditions with and without grain refiner. Temperature and composition measurements and sump profiles are compared to the numerical results. The comparison shows excellent agreement for the grain refined case. It is believed that an incorrect assumption about the grain structure prevents good agreement in the non-grain refined billet.

The Grain Size Evolution of AZ31 Profiles as a Function of Different Casting Conditions

2005 ◽  
Vol 488-489 ◽  
pp. 349-356 ◽  
Author(s):  
Franka Pravdic ◽  
H. Kilian ◽  
M. Brandecker ◽  
C. Wögerer ◽  
G. Traxler
Keyword(s):  
Grain Size ◽  
Casting Machine ◽  
Az31 Alloy ◽  
Extrusion Process ◽  
Direct Chill ◽  
Mechanical Tests ◽  
Direct Chill Casting ◽  
Metallographic Analysis ◽  
Process Chain ◽  
Chill Casting

The present paper describes the microstructural evolution of AZ31 alloy along the process chain, from the melt treatment, the direct chill casting up to the extrusion process. Each step in the process chain will be considered in order to design the appropriate properties of the endproducts. The research has been done in industrial scale at ARC Leichtmetallkompetenzzentrum Ranshofen GmbH (LKR), in order to analyse the grain size dependency of AZ31 alloy on different casting conditions. The casting trials with and without grain refinement were carried out at the vertical direct chill casting machine MAGNUMCAST®. After the extrusion process metallographic analysis and mechanical tests were carried out.

Direct Chill Casting of Aluminum Alloys: Modeling and Experiments on Industrial Scale Ingots

2002 ◽  
Vol 124 (5) ◽  
pp. 947-953 ◽  
Author(s):  
Christopher J. Vreeman ◽  
J. David Schloz ◽  
Matthew John M. Krane
Keyword(s):  
Casting Process ◽  
Direct Chill ◽  
Solid Particles ◽  
Direct Chill Casting ◽  
Grain Structure ◽  
Temperature Fields ◽  
Industrial Scale ◽  
Grain Refiner ◽  
Chill Casting ◽  
Continuum Mixture Model

A continuum mixture model of the direct chill casting process is compared to experimental results from industrial scale aluminum billets. The model, which includes the transport of free-floating solid particles, can simulate the effect of a grain refiner on macrosegregation and fluid flow. It is applied to an Al-6 wt% Cu alloy and the effect of grain refiner on macrosegregation, sump profile, and temperature fields are presented. Two 45 cm diameter billets were cast under production conditions with and without grain refiner. Temperature and composition measurements and sump profiles are compared to the numerical results. The comparison shows some agreement for the grain refined case. It is believed that an incorrect assumption about the actual grain structure prevents good agreement in the non-grain refined billet.

scholarly journals Motion and Distribution of Floating Grain in Direct-Chill Casting of Aluminum Alloys: Experiments and Numerical Modeling

Materials ◽  
2020 ◽  
Vol 13 (23) ◽  
pp. 5379
Author(s):  
Qipeng Dong ◽  
Yanbin Yin ◽  
Zhen Zhu ◽  
Hiromi Nagaumi
Keyword(s):  
Numerical Modeling ◽  
Aluminum Alloys ◽  
Mushy Zone ◽  
Central Region ◽  
Direct Chill ◽  
Direct Chill Casting ◽  
Grain Structure ◽  
Chill Casting ◽  
Centerline Segregation ◽  
Negative Segregation

Sedimentation of free-floating grains is the main origin of the negative centerline segregation in direct-chill casting of aluminum alloys. This study examines the motion and distribution of the floating grains during casting using experimental measurements and numerical modeling. The typical floating grains consisting of interior solute-lean coarse dendrites and periphery fine dendrites were experimentally observed only in the central region of the billet along with the negative segregation. The billet exhibits the strongest segregation at the center where the most floating grains are found. In simulations, under the action of the convection and the underlying forces, the grains floating in the transition region exhibit different motion behaviors, i.e., settling to the mushy zone, floating in the slurry zone, and moving upward to the liquid zone. However, most grains were transported to the central region of the billet and then were captured by the mushy zone and settled. Therefore, the floating grains comprise the largest share of the grain structure at the center of the billet, in agreement with the experimental results. Moreover, the simulation results indicate that the increased size of the grains promotes the sedimentation of the floating grains. These results are important for the future alleviation of negative centerline segregation in direct-chill casting of aluminum alloys.

scholarly journals Microstructures and Macrosegregation of Al–Zn–Mg–Cu Alloy Billet Prepared by Uniform Direct Chill Casting

Materials ◽  
2021 ◽  
Vol 14 (4) ◽  
pp. 708
Author(s):  
Li Zhou ◽  
Yajun Luo ◽  
Zhenlin Zhang ◽  
Min He ◽  
Yinao Xu ◽  
...  
Keyword(s):  
Mold Wall ◽  
Direct Chill ◽  
Element Distribution ◽  
Direct Chill Casting ◽  
Electromagnetic Stirring ◽  
Alloying Elements ◽  
Alloying Element ◽  
Casting Method ◽  
Chill Casting ◽  
Cu Alloy

In this study, large-sized Al–Zn–Mg–Cu alloy billets were prepared by direct chill casting imposed with annular electromagnetic stirring and intercooling; a process named uniform direct chill casting. The effects of uniform direct chill casting on grain size and the alloying element distribution of the billets were investigated and compared with those of the normal direct chill casting method. The results show that the microstructures were refined and the homogeneity of the alloying elements distribution was greatly improved by imposing the annular electromagnetic stirring and intercooling. In uniform direct chill casting, explosive nucleation can be triggered, originating from the mold wall and dendrite fragments for grain refinement. The effects of electromagnetic stirring on macrosegregation are discussed with consideration of the centrifugal force that drives the movement of melt from the central part towards the upper-periphery part, which could suppress the macrosegregation of alloying elements. The refined grain can reduce the permeability of the melt in the mushy zone that can restrain macrosegregation.

Effect of process parameters on structure and macrosegregation upon direct chill casting of Mg–Nd–Zn–Zr alloy

2011 ◽  
Vol 27 (1) ◽  
pp. 275-281 ◽  
Author(s):  
X. W. Zheng ◽  
J. Dong ◽  
N. Zhou ◽  
P. H. Fu ◽  
S. S. Yao ◽  
...  
Keyword(s):  
Process Parameters ◽  
Direct Chill ◽  
Direct Chill Casting ◽  
Chill Casting ◽  
Zr Alloy

scholarly journals Konveksi Paksa Selama Pembekuan Paduan Al- Wt% Cu dan Pengaruhnya Terhadap Segregasi

2016 ◽  
Vol 36 (1) ◽  
pp. 16
Author(s):  
Shinta Virdhian
Keyword(s):  
Direct Chill ◽  
Direct Chill Casting ◽  
Chill Casting

ABSTRAKMakrosegregasi adalah ketidakseragaman komposisi pada jarak yang dapat dibandingkan dengan ukuran produk,contohnya mm, cm bahkan meter.Ketidakseragaman komposisi ini akan berakibat menurunnya sifat mekanis dari hasil produk direct chill casting pada Aluminium ingot/billet. Pada paduan Al-4%Cu,macrosegregasi dimaksudkan ketidakseragaman komposisi Cu pada ingot/billet. Dalam penelitian ini, pompa screw yang dirancang khusus  untuk memproduksi dan memodifikasi aliran dalam logam cair selama pembekuan paduan Al-4% Cu. Pompa screw digunakan unuk mempoduksi aliran konveksi paksa sejajar atau berlawanandengan konveksi alami dengan cara mengatur arah dan kecepatan putaran. Hasil analisa struktur mikro menunjukkan bentuk butiran yang equiaxed dendriticuntuk semua kasus dalam penelitian ini. Peningkatan intensitas dari konveksi paksa akan menurunkan ukuran butir secara kualitatif, walaupun secara kuantitatif tidakditemukan nilai perbedaan yang signifikan.  Analisa makrosegregasi menunjukkan bahwa konveksi paksa searah dengan konveksi alami menyebabkan segregasi positif (presentase Cu yang lebih besar dari rata-rata) di bagian tengah dari bilet, peningkatan kecepatan lebih lanjut akan menyebabkan variasi komposisi menjadi lebih besardan makrosegragasi akan sulit untuk dikontrol.Konveksi paksa yang berlawanan dengan segregasi akan menekan konveksi alami sehingga dihasilkan variasi komposisi yang lebih kecil.       Kata kunci: proses direct chill casting, makrosegregasi, konveksi paksa 

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