Continuous Fabrication of Sound Semi-Solid Slurry for Rheoforming

2006 ◽  
Vol 116-117 ◽  
pp. 425-428 ◽  
Author(s):  
Hong Min Guo ◽  
Xiang Jie Yang
Keyword(s):  
High Efficiency ◽  
Primary Phase ◽  
Process Window ◽  
Equivalent Diameter ◽  
Forming Process ◽  
Pouring Temperature ◽  
Initial Stage ◽  
Semi Solid ◽  
Continuous Fabrication ◽  
Low Superheat

An alternative method has been proposed for the continuous and sample production of SSM slurry for the rheo-forming process. The process named “Low Superheat Pouring with a Shear Field (LSPSF)” dose not use the conventional stirring process, instead, it uses solidification conditions to control nucleation, nuclei survival and grain growth by means of low superheat pouring, vigorous mixing and rapid cooling during the initial stage of solidification combined with thereafter a much slower cooling. The method has been applied to A356, 201 and A380 Al-alloys. The primary phases present in average equivalent diameter of 40-70μm, 35-50μm and 50-70μm for A356, 201 and A380, respectively. The morphology of primary phases is nearly spherical with shape factor of 0.78-0.86, 0.71-0.83 and 0.85-0.96 for A356, 201 and A380, respectively. For each of those alloys, there is no eutectic entrapped within the primary phase. The advantages of the LSPSF include process simplicity with high efficiency, easy incorporation into existing metal forming installation without infrastructure changes and a wide process window for pouring temperature.

Effect of Serpentine Channel Pouring Process on the Microstructure of Semi-Solid 6061 Aluminum Alloy Slurry

2022 ◽  
Vol 327 ◽  
pp. 255-262
Author(s):  
Nai Yong Li ◽  
Wei Min Mao ◽  
Xiao Xin Geng ◽  
Peng Yu Yan
Keyword(s):  
Grain Size ◽  
Aluminum Alloy ◽  
Shape Factor ◽  
Primary Phase ◽  
High Quality ◽  
Pouring Temperature ◽  
6061 Aluminum Alloy ◽  
Serpentine Channel ◽  
Channel Surface ◽  
Semi Solid

The semi-solid slurry of 6061 aluminum alloy was prepared by the serpentine channel pouring process. The influence of graphite serpentine channel and copper serpentine channel on the slurry was comparative analyzed. The effect of pouring temperature on the slurry microstructure was also investigated. The results indicate that both copper and graphite serpentine channel can be used to prepare semi-solid slurry with spherical primary grains. Compared with a permanent casting, the microstructure of the semi-solid slurry was significantly improved and refined. With the increase of pouring temperature, the average equivalent grain diameter of the primary phase grains in the semi-solid slurry increases gradually, but the shape factor decreases gradually. When the pouring temperature increased from 675 °C to 690 °C, a high quality semi-solid slurry can be obtained. Comparing the two kinds of serpentine channel, it is found that the copper serpentine channel can make the primary grains finer, and the average equivalent grain size was 63 μm. However, the solidified shell near the inner graphite serpentine channel surface was thinner than that of the copper serpentine channel. In conclusion, the graphite serpentine channel is more suitable for preparing semi-solid 6061 aluminum alloy slurry.

Prepartion of Semisolid AM60 Alloy by Novel Self-Inoculation Method

2011 ◽  
Vol 189-193 ◽  
pp. 3804-3809 ◽  
Author(s):  
Yuan Dong Li ◽  
Bo Xing ◽  
Ying Ma ◽  
Ti Jun Chen ◽  
Yuan Hao
Keyword(s):  
Slope Angle ◽  
Dendritic Structure ◽  
Primary Phase ◽  
Chemical Pollution ◽  
Cooling Channel ◽  
Dendritic Microstructure ◽  
Pouring Temperature ◽  
Inoculation Method ◽  
Semi Solid ◽  
Slurry Preparation

A research focus on semi-solid metal processing is the preparation of semi-solid slurry with non-dendritic microstructure. During the past several decades, people tended to obtain the non-dendritic structure by stirring melt of alloy which downs to the semi-solid temperature range, such as mechanical stirring and electromagnetic stirring; In recent years, with the technological innovation of semi-solid slurry preparation turned to be more convenient and efficient, most of these processes are based on the control of nucleation and growth process of primary phase during solidification, such as NRC, SSR, SLC, SEED, and CRP. In this paper, a novel process, named as “Self-Inoculation Method (SIM)”, has been proposed for semi-solid slurry preparation. The process involves self-inoculants addition to the melt, and then pouring the melt to mould through a multi-stream mixed cooling channel. The melt was avoided chemical pollution due to the particles of self-inoculants from the same composition as the melt. The semi-solid billets of AM60 alloy with non-dendritic structure were prepared by SIM. The effects of process parameters on the microstructure and the mechanism on refinement of alloy were investigated. The results indicate that pouring temperature, addition amount of self-inoculants and slope angle of the cooling channel are key factors for SIM process. The optimized parameters for the billet preparation of AM60 alloy are obtained: pouring temperature is at 680°C~700°C；addition of self-inoculants are between 5%~7% (mass fraction)；slope angle of the cooling channel is at 30°~45°. The heterogeneous nucleation was enhanced as the addition of self-inoculants; the formation of chill crystal and the fragmentation of dendrites because of cooling and shearing of the cooling channel, resulting in the increase of grains density and a small grain size.

Preparation of Semi-Solid A390 Aluminum Alloy Slurry through a Serpentine Pouring Channel

2019 ◽  
Vol 285 ◽  
pp. 169-175 ◽  
Author(s):  
Wei Min Mao ◽  
Peng Yu Yan ◽  
Z.K. Zheng
Keyword(s):  
Aluminum Alloy ◽  
Good Method ◽  
Primary Silicon ◽  
Forming Process ◽  
Pouring Temperature ◽  
Average Shape ◽  
Traditional Process ◽  
Semi Solid ◽  
A390 Alloy ◽  
Inner Channel

In order to study the possibility of refining the primary silicon grains in the microstructure of hypereutectic Al-Si alloy through a serpentine pouring channel, the semi-solid slurry of A390 aluminum alloy was prepared through a water-cooled copper serpentine pouring channel, which is a new method proposed recently for semi-solid forming process, and the effect of pouring temperature on the slurry microstructure was investigated. The results show that the slurry of A390 aluminum alloy with refined primary silicon grains can be prepared under given conditions and especially when the pouring temperatures is 690°C, the primary silicon grains can be refined obviously, the equivalent silicon grain size is 19.7mm and the average shape factor is about 0.7. The analysis shows that the chilling effect of the inner channel wall precipitates a large number of primary silicon nuclei, and so the primary silicon grains are refined greatly. Meanwhile, the subsequent alloy melt washing also promotes the separation of primary silicon grains from the inner wall and the primary silicon grains are further refined. The work undertaken demonstrates eventually that the serpentine pouring channel process is a good method for refining the primary silicon grains in hypereutectic A390 alloy rather than using chemical fining agent phosphorus as in traditional process, and provides an alternative process choice.

scholarly journals The Fabrication of Automobile Components by Applying Electromagnetic Stirring in Semisolid Process

2011 ◽  
Vol 2011 ◽  
pp. 1-12
Author(s):  
H. H. Kim ◽  
C. G. Kang
Keyword(s):  
Primary Phase ◽  
Electromagnetic Stirring ◽  
Simulation Studies ◽  
Forming Process ◽  
Pouring Temperature ◽  
Feed Stock ◽  
Stirring Time ◽  
Automobile Components ◽  
Semisolid Process ◽  
Tip Velocity

This paper describes a rheo-forming process for the development of automobile components, such as knuckle, by using rheology material with electromagnetic stirring (EMS) system equipment. The effects of several process and metallurgy parameters such as stirring current, stirring time, pouring temperature, forming pressure, tip velocity, fraction of primary phase, and its morphology and distribution, on the final products are reviewed and discussed. A variety of simulation studies are conducted. In addition, the effect of the vacuum-assisted method on the performance of rheo-forged products is introduced. The EMS is an effective process to improve a feed stock in the rheo-forming process with improved mechanical properties.

Effect of Pouring Temperature and Holding Time at Semi-Solid Region on the Morphology of Primary Solid Phase in Semi-Solid Slurry

2006 ◽  
Vol 510-511 ◽  
pp. 782-785 ◽  
Author(s):  
Suk Won Kang ◽  
Ki Bae Kim ◽  
Dock Young Lee ◽  
Jung-Hwa Mun ◽  
Eui Pak Yoon
Keyword(s):  
Solid Phase ◽  
Holding Time ◽  
Pouring Temperature ◽  
Solid Region ◽  
Semi Solid

Mechanical Properties of Thixoformed 7075 Feedstock Produced via the Direct Thermal Method

2015 ◽  
Vol 651-653 ◽  
pp. 1569-1574 ◽  
Author(s):  
Asnul Hadi Ahmad ◽  
Sumsun Naher ◽  
Dermot Brabazon
Keyword(s):  
Mechanical Properties ◽  
Tensile Strength ◽  
Solid State ◽  
Tensile Testing ◽  
Thermal Method ◽  
Test Unit ◽  
Pouring Temperature ◽  
Injection Test ◽  
Semi Solid ◽  
Conventionally Cast

Abstracts: This paper presents an overview of measured mechanical properties of thixoformed aluminium 7075 feedstock produced by the direct thermal method (DTM). The DTM feedstock billets were processed with a pouring temperature of 685 °C and holding periods of 20 s, 40 s and 60 s before being quenched and subsequently thixoformed. A conventionally cast feedstock billet was produced with a pouring temperature of 685 °C and was allowed to solidify without quenching. The feedstock billets were later formed by an injection test unit in the semi-solid state. Tensile testing was then conducted on the thixoformed feedstock billets. Tensile properties for 7075 DTM thixoformed feedstock billets were found significantly influenced by the thixoformed component density. Samples with longer holding times were found to have higher density and higher tensile strength.

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.

Formation Mechanism of Thixotropic Microstructure of AM60 Alloy during Solidification

2014 ◽  
Vol 1030-1032 ◽  
pp. 86-89
Author(s):  
Bo Xing
Keyword(s):  
Formation Mechanism ◽  
Solid Substrate ◽  
Research Field ◽  
Primary Phase ◽  
Solid Particles ◽  
Metallographic Analysis ◽  
Semisolid Slurry ◽  
Dendritic Microstructure ◽  
Quenching Method ◽  
Semi Solid

A research field on semi-solid metal processing is the preparation of semi-solid slurry with non-dendritic microstructure. Nowadays, with the technological innovation of semi-solid slurry preparation, people turn to produce the non-dendritic semisolid microstructure by locally cooling of the alloy melt during solidification. Therefore, it is necessary to investigate the formation mechanism of the non-dendritic microstructure formation because the primary phase undergoes a specially controlled nucleation and growth which distinctly different from the commom solidification. In this paper, the semisolid slurry of AM60 alloy was produced by Self-Inoculation Method (SIM), and the microstructure evolution of primary α-Mg was investigated by water quenching method and metallographic analysis. The results indicate that the semisolid microstructure of AM60 alloy produced by SIM composed of small and globular α-Mg particles, and these grains undergone a coarsing process during quiescent holding. The solid substrate caused by the fusion of solid particles and the dendritic fragments caused by melt flow caused the grain multiplication, and then the grain undergone a steadily growth because of the uniform temperature distribution, resulting in the increase of grains density and a small grain size of the AM60 semisolid slurry.

Semi-Enclosed Cold Forging Process Analysis and Progressive Die Design of CPU Fin

2008 ◽  
Vol 575-578 ◽  
pp. 174-179
Author(s):  
Juan Hua Su ◽  
Feng Zhang Ren ◽  
Lei Wang
Keyword(s):  
Production Efficiency ◽  
High Efficiency ◽  
Process Analysis ◽  
Die Design ◽  
Cold Forging ◽  
Forming Process ◽  
Element Analysis ◽  
Whole Process ◽  
Progressive Dies ◽  
Transfer Unit

This paper analyzes the forming process methods of fin used in CPU chip to emit heat. The whole process is blanking, the first forging forming, the second forging (sizing), and trimming. The chamfer design of CPU fin blank is simulated by finite element analysis. The optimized chamfer 1.6 mm is available. Semi-enclosed cold forging of progressive dies is put forward. The newly designed transfer unit is applied, which unifies the merit of high efficiency of the progressive dies and the high material-using ratio of the project die. Quick disassembly structure is designed and pins are used as quick disassembly pins by means of ball bearing bushing. The unique processing of the shearing scrap structure is adopted when designing the inverted trimming dies. Compared with the traditional die, the mechanization and electrization are realized to increase the production efficiency and get highly precise CPU fin.

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