Recycling Al-Si Alloy by Semisolid Material Dragged during Continuous-Casting Strip Processing

2022 ◽  
Vol 327 ◽  
pp. 293-299
Author(s):  
Antonio de Pádua Lima Filho ◽  
Lucas Veronez Goulart Ferreira ◽  
Pedro Barbosa de Oliveira Neto ◽  
Fabian Hoisand ◽  
Rodrigo Alessandro Nunes de Oliveira ◽  
...  
Keyword(s):  
Maximum Stress ◽  
Cooling System ◽  
Liquidus Line ◽  
Pouring Temperature ◽  
Cooling Slope ◽  
Stress Maximum ◽  
Internally Cooled ◽  
Metallic Strip ◽  
Good Contact

Recycled Al–Si (9.2%) alloy contaminated with Fe (0.3%), Pb (3.1%) and Sn (11.4 %) was cast and poured at 650 oC, approximately 50 oC above the liquidus line. A cooling slope was used to obtain a semisolid material that feeds a ceramic nozzle designed to function as a good contact area for solidification and improve the quality of strip casting. The internally cooled material rolls in soluble oil (1 oil / 9 water) at a rate of 0.2 l/s and works as a heat exchanger which drags the metallic slurry puddle generated at the roll surface at a speed of 0.12 m/s. This forms a metallic strip with a thickness of 2 mm and a width varying from approximately 45 mm to 60 mm. The cooling system of the rolls, combined with four springs placed at the housing screw, prevented adhering of the metallic strip during production at a pressure of approximately 450 N. Cracks were observed on the strip surfaces; however, these defects did not interrupt the continuous flow of the solidified strip during manufacturing. The strip’s poor surface quality could be related to the Pb and Sn contamination as well as cold cracks due to the low pouring temperature. Al-Si eutectics positioned at a grain boundary of α-Al globular structures, as well as the presence of a Sn phase, resulted in a metallic strip with a yield stress, maximum stress and elongation of 94.5 MPa, 100.2 MPa and 1.6%, respectively.

Preparation of Semisolid A356 Alloy by a Cooling Slope Processing

2011 ◽  
Vol 675-677 ◽  
pp. 767-770 ◽  
Author(s):  
Jun Xu ◽  
Tong Min Wang ◽  
Zong Ning Chen ◽  
Jing Zhu ◽  
Zhi Qiang Cao ◽  
...  
Keyword(s):  
A356 Alloy ◽  
A356 Aluminum Alloy ◽  
Forming Process ◽  
Pouring Temperature ◽  
Cooling Slope ◽  
Optimum Parameters ◽  
Grain Structures ◽  
Semisolid Forming ◽  
Size And Morphology ◽  
A356 Aluminum

In order to obtain the non-dendritic feedstock for the semisolid forming process, a cooling slope processing was used. In this work, the effects of the angle, length of cooling slope and pouring temperature on the microstructure of A356 aluminum alloy were investigated. It showed that these parameters affect the size and morphology of α-Al phase to some extent. The results indicate that a pouring temperature of 650°C and a cooling slope with 45° in angle and 50 cm in length are the optimum parameters for preparing fine and globular grain structures. To eliminate the solidification shell formed in the surface of cooling slope, a nitride dope was coated on the surface of the cooling slope.

Evaluation of Strip Rolling Directly from the Semi-Solid State

2006 ◽  
Vol 116-117 ◽  
pp. 433-436 ◽  
Author(s):  
Antonio de Pádua Lima Filho ◽  
Márcio Iuji Yamasaki
Keyword(s):  
Solid State ◽  
Cooling System ◽  
Solid Alloy ◽  
Strip Rolling ◽  
Tin Alloys ◽  
Cooling Slope ◽  
Quality Issue ◽  
Lower Roller ◽  
Semi Solid ◽  
Strip Quality

The aim of this work is to study the solidification conditions necessary to produce good quality/low defect metal alloy strip when thixorolling directly from the semi-solid state. To facilitate the study lead/tin alloys were chosen for their relatively low operating temperature. The objective is to extrapolate these findings to the higher temperature aluminium alloys. Three alloys (70%Pb- 30%Sn, 60%Pb-40%Sn, 50%Pb-50%wtSn) were used particularly to study the influence of the solidification interval. The equipment consists of a two roll mill arranged as an upper and lower roller, where both rollers are driven at a controlled speed. The lower roller is fed with semi solid alloy through a ceramic nozzle attached to the lower end of a cooling slope. Several types of nozzle and their position at the roller were tested. This produced different solidifications and consequently different finished strip. The alloys were first cast and then poured onto the cooling slope through a tundish in order to create a continuous laminar flow of slurry and uniformity of metal strip quality. The pouring was tested at different positions along the slope. The cooling slope was coated with colloidal graphite to promote a smooth slurry flow and avoid the problem of adherence and premature solidification. The metallic slurry not only cools along the slope but is also initially super-cooled to a mush by the lower roller whilst at room temperatures, thus enabling thixorolling. It was also found that the nozzle position could be adjusted to enable the upper roller to also contribute to the solidification of the metallic slurry. However the rollers and the cooling slope naturally heat up. Temperature distribution in these zones was analysed by means of three thermocouples positioned along the cooling slope and a fourth in the base of the semi solid pool within the nozzle. The objective being to design an optimum pouring and cooling system. The formed strip was cooled down to room temperature with a shower of water. Microstructures of the thixorolling process were analysed. The differences in solidification conditions resulted in differing qualities of finished strip and corresponding defect types, all of which are a serious quality issue for the rolled product.

scholarly journals Effects of an integrated harvest system on the quality of olive fruit for small producers

2022 ◽  
Vol 72 (4) ◽  
pp. e436
Author(s):  
E. Plasquy ◽  
G. Blanco-Roldán ◽  
M.C. Florido ◽  
J.M. García
Keyword(s):  
Skin Color ◽  
Value At Risk ◽  
Cooling System ◽  
Economic Value ◽  
Optimum Conditions ◽  
Olive Fruit ◽  
Harvesting Method ◽  
Small Producers ◽  
Storage Times

Small producers confront specific challenges when they opt to produce high-quality olive fruit. Limited resources for investing in harvest machinery and manpower are the main reasons for continuing a traditional harvest method that puts the final product and its economic value at risk. This paper discusses the efficiency of an integrated harvest system as a possible solution to these specific challenges. The system is formed by a newly designed manual harvesting device and the use of a cooling room near the olive grove. Both systems were evaluated to assess their feasibility for optimum conditions before processing. The combined effect of the harvesting method and cold storage on the fruit characteristics (incidence of decay, skin color, weight loss, firmness, respiration, and ethylene production) was evaluated on three different varieties (‘Arbequina’, ‘Picual’ and ‘Verdial’) and four different storage times (0, 4, 8, and 14 days). The results indicate that the proposed harvesting method in combination with an appropriate cooling system offers an affordable alternative for obtaining fruit with the best physiological characteristics.

Formation of Globular Microstructure in A380 Aluminum Alloy by Cooling Slope Casting

2011 ◽  
Vol 264-265 ◽  
pp. 272-277 ◽  
Author(s):  
Nurşen Saklakoğlu ◽  
S. Gencalp ◽  
Şefika Kasman ◽  
İ.E. Saklakoğlu
Keyword(s):  
Aluminum Alloy ◽  
Slope Angle ◽  
Casting Process ◽  
Solid Particles ◽  
Inclined Plate ◽  
Pouring Temperature ◽  
Cooling Slope ◽  
Semi Solid ◽  
Cooling Slope Casting ◽  
The Many

Thixoforming and related semi-solid processing (SSP) methods require thixotropic materials. One of the many SSP techniques is the cooling slope (CS) casting process, which is simple and has minimal equipment requirements, and which is able to produce feedstock materials for semisolid processing. When the feedstock is reheated to the semisolid temperature range, non-dendritic, spheroidal solid particles in a liquid matrix suitable for thixoforming are obtained. In this study, equipment for the CS technique was first established, and then the effects of the pouring temperature and inclined slope angle on the microstructures of A380 aluminum alloy (ISOAlSi8Cu3Fe) were studied. Optimum parameters for thixoforming experiments were selected, and it was found that the microstructure produced by the inclined plate depended on its angle and the pouring temperature.

scholarly journals Methodology of Supervision by Analysis of Thermal Flux for Thermal Conduction of a Batch Chemical Reactor Equipped with a Monofluid Heating/Cooling System

2012 ◽  
Vol 2012 ◽  
pp. 1-10
Author(s):  
Ghania Henini ◽  
Fatiha Souahi ◽  
Ykhlef Laidani
Keyword(s):  
Thermal Conduction ◽  
Cooling System ◽  
Batch Reactor ◽  
Thermal Flux ◽  
Exothermic Reaction ◽  
Chemical Reactor ◽  
Thermal Control ◽  
Ride Quality ◽  
Heating And Cooling

We present the thermal behavior of a batch reactor to jacket equipped with a monofluid heating/cooling system. Heating and cooling are provided respectively by an electrical resistance and two plate heat exchangers. The control of the temperature of the reaction is based on the supervision system. This strategy of management of the thermal devices is based on the usage of the thermal flux as manipulated variable. The modulation of the monofluid temperature by acting on the heating power or on the opening degrees of an air-to-open valve that delivers the monofluid to heat exchanger. The study shows that the application of this method for the conduct of the pilot reactor gives good results in simulation and that taking into account the dynamics of the various apparatuses greatly improves ride quality of conduct. In addition thermal control of an exothermic reaction (mononitration) shows that the consideration of heat generated in the model representation improve the results by elimination any overshooting of the set-point temperature.

A strain-based tensor polynomial failure criterion for anisotropic materials

1988 ◽  
Vol 23 (4) ◽  
pp. 179-186 ◽  
Author(s):  
W Zhang ◽  
K E Evans
Keyword(s):  
Epoxy Resin ◽  
Plane Stress ◽  
Failure Criterion ◽  
Maximum Stress ◽  
Failure Criteria ◽  
Anisotropic Materials ◽  
Maximum Strain ◽  
Stress Space ◽  
Failure Envelope ◽  
Stress Maximum

A strain-based tensor polynomial failure criterion for anisotropic materials is proposed with explicit derivations given in both strain and stress space. The physical distinction between this strain-based criterion and the current stress-based tensorial criterion of Tsai and Wu, is clarified. The viability of the proposed criterion is shown by its application to a graphite—epoxy resin lamina under plane stress. The allowed loadings and failure envelope of this lamina are predicted. Comparison is made with existing failure criteria (both stress-based and strain-based), in particular the maximum stress, maximum strain, and Tsai-Wu criteria.

Making Non-Dendritic Structure via Modified Cooling Slope Technique

2014 ◽  
Vol 915-916 ◽  
pp. 602-607 ◽  
Author(s):  
Y.T. Chen ◽  
Chi Y.A. Tsao ◽  
C.H. Chiang
Keyword(s):  
Cooling Rate ◽  
Solid Fraction ◽  
Process Parameters ◽  
Water Flow Rate ◽  
Slope Angle ◽  
Dendritic Structure ◽  
Pouring Temperature ◽  
Cooling Slope ◽  
Inclined Slope ◽  
Dendritic Microstructures

The cooling slope technique has been developed in recent years, which controls the nucleation and growth of the primary grains during solidification to achieve fine and non-dendritic microstructures. In this study, A356 Al alloys were processed through a modified cooling slope technique to obtain fine, non-dendritic microstructures, in which the cooling rate of the cast crucible was controlled. Three process parameters, namely pouring temperature, inclined slope angle, and the cooling rate of the cast crucible, were varied during the processing. The cooling slope was water-cooled with a constant water flow rate. The solid fraction and the size distributions of the primary grains along the vertical and horizontal positions of the cast ingots were measured individually. The macro-segregation was examined in terms of the distribution of the solid fraction. The yields of the ingots were calculated for studying the efficiency of the cooling slope technique. The effects of the three process parameters on the microstructures, macro-segregation, and yields were studied by the Taguchi method.

Study on Internal Quality of Billets for 20CrMnTiH Steel

2014 ◽  
Vol 941-944 ◽  
pp. 132-137
Author(s):  
Hong Guang Li ◽  
Tian Ming Chen ◽  
Liang Chen ◽  
Jia Qi Wang ◽  
Wen Zhong Yang
Keyword(s):  
Quality Control ◽  
Quality Improvement ◽  
Casting Speed ◽  
Cooling System ◽  
Current Intensity ◽  
Internal Quality Control ◽  
Internal Quality ◽  
Secondary Cooling ◽  
Carbon Segregation

According to the requirement of 20CrMnTiH steel, the effects of casting peed, EMS current intensity and secondary cooling system on internal quality of billets are studied. The results show that, it is beneficial to internal quality control of 20CrMnTiH billets when the casting speed is in the range of 1.2~1.4m/min, and when the current intensity of EMS is 380A, the level of center porosity can be controlled in 1.0, the index of carbon segregation can be controlled in 1.08 and equiax crystal ratio reaches 34.9%. Furthermore, it is beneficial to internal quality improvement when weak secondary cooling system is adopted. With the application of the studies, the quality of billet macrostructure and hardenability can meet the requirement of 20CrMnTiH steel.

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