Application of Multiphase Modelling in Semi-Solid Die Casting: Blister Prediction

2016 ◽  
Vol 256 ◽  
pp. 139-145 ◽  
Author(s):  
Xiao Gang Hu ◽  
Qiang Zhu ◽  
Helen V. Atkinson ◽  
Min Luo ◽  
Fan Zhang ◽  
...  
Keyword(s):  
Solid Phase ◽  
Die Casting ◽  
Phase Segregation ◽  
Casting Process ◽  
Alloy System ◽  
Design Tool ◽  
System Modelling ◽  
Solid Alloy ◽  
Homogeneous Fluid ◽  
Semi Solid

One-phase modelling is widely used as an optimization and design tool for semi-solid casting process. By this approach, semi-solid alloy is taken as a homogeneous fluid and flow behaviours are represented by using the rheological properties of the mixture. A single set of conservation equations is solved to simulate the mould filling, without considering the different motilities between the liquid and the solid phase. Therefore, defects due to phase segregation cannot be predicted and particle tracking cannot be carried out. This study is focused on multiphase (i.e. a liquid-particle-air system) modelling during the semi-solid filling process of a thin-walled component. By using this approach, the solid phase is treated as a power law fluid and the phase interactions among the phases are introduced for the semi-solid alloy system. Practical semi-solid die casting is carried out for verification of phase segregation. The final distribution of air is calculated and proved by practical blistering examination. The simulation results are verified to be accurate in a reasonable range, indicating an approach for modelling semi-solid filling including the formation (and avoidance) of blisters.

Effect of Slurry Temperature Distribution on Semi-Solid Die Casting

2016 ◽  
Vol 256 ◽  
pp. 107-112 ◽  
Author(s):  
Wen Ying Qu ◽  
Fan Zhang ◽  
Jiao Jiao Wang ◽  
Xiao Gang Hu ◽  
Qiang Zhu
Keyword(s):  
Temperature Distribution ◽  
Die Casting ◽  
Casting Process ◽  
Flow Patterns ◽  
Solid Alloy ◽  
Filling Process ◽  
Air Entrapment ◽  
Die Filling ◽  
Die Casting Process ◽  
Semi Solid

Semi-solid alloy slurries with different temperature distributions have diverse flow patterns of the slurries during die casting filling process. This different flow patterns can lead to various degrees of front separation of the slurry metal from the die cavity during die filling process. This separation can result in air entrapment, which is one of the origins for gas porosities and blisters occurred during followed heat treatment. Therefore, in this paper, the effects of slurry temperature distribution on filling patterns during die casting process were investigated. Based on partial filling experiments, positive and negative gradient temperature distribution, together with two homogeneous conditions 575°C, 579°C were compared by computer simulation. The results indicate that the positive gradient temperature condition of 357.0 slurry is more suitable for the semi-solid die casting of the connector, and 7 °C temperature gradient in slurry is appropriate for good filling.

Development of Semi-Solid Die Casting Product Design and Die Design Technology for Aluminium Alloy Clamp

2016 ◽  
Vol 256 ◽  
pp. 334-339 ◽  
Author(s):  
Song Chen ◽  
Fan Zhang ◽  
You Feng He ◽  
Da Quan Li ◽  
Qiang Zhu
Keyword(s):  
Product Design ◽  
Die Casting ◽  
Casting Process ◽  
Die Design ◽  
Thick Wall ◽  
Thin Wall ◽  
Gating System ◽  
Cross Sectional ◽  
Die Casting Process ◽  
Semi Solid

Semi-solid slurry has significantly higher viscosity than liquid metal. This character of fluidity makes product design and die design, such as gating system, overflow and venting system, be different between these two die casting processes. In the present paper, taking a clamp product as an example, analyses the product optimization and die design by comparing the experimental and computational numerical simulation results. For the clamp, product structure is designed to be suitable for characters of SSM die casting process. The gating system is designed to be uniform variation of thickness, making the cross-sectional area uniformly reduce from the biscuit to the gate. This design ensures semi-solid metal slurry to fill die cavity from thick wall to thin wall. Gate position is designed at the thickest location, the gate shape of semi-solid die casting is set to be much bigger than traditional liquid casting. A good filling behaviour can be achieved by aforementioned all these design principles and it will be helpful to the intensification of pressure feeding after filling.

Die Design for Main Bearing Cap of Engine Block Based Semi-Solid Die Casting Process and the Comparison Analysis with Squeeze Casting Process

2019 ◽  
Vol 285 ◽  
pp. 429-435 ◽  
Author(s):  
Song Chen ◽  
Da Quan Li ◽  
Fan Zhang ◽  
Min Luo ◽  
Xiao Kang Liang ◽  
...  
Keyword(s):  
Squeeze Casting ◽  
Die Casting ◽  
Dendritic Structure ◽  
Casting Process ◽  
Die Design ◽  
Main Bearing ◽  
Block Based ◽  
Semi Solid ◽  
Bearing Cap ◽  
Squeeze Casting Process

There are two new processes to development automobile structural components which have certain thickness. In the present paper, taking a main bearing cap product as an example, analyses die design by comparing the experimental and computational numerical simulation results. For the main bearing cap, product structure and mold design were designed to be suitable for characters of SSM die casting and squeeze process. Semi-solid slurry has significantly higher viscosity than liquid metal. This character of fluidity and solid fraction phase make the flow condition more laminar than liquid squeeze casting with the partial fill experiment. And compared with squeeze casting process, the globular shape grain size is smaller than dendritic structure. And mechanical property result shows that the elongation of SSM die casting can achieve more than twice than squeeze casting.

Numerical Simulation on the Filling Process of Rheological Die Casting and Forming Defects Analysis

2012 ◽  
Vol 192-193 ◽  
pp. 293-298 ◽  
Author(s):  
Fan Zhang ◽  
Nan Nan Song ◽  
Jun Zhang ◽  
Yong Lin Kang ◽  
Qiang Zhu
Keyword(s):  
Numerical Simulation ◽  
Die Casting ◽  
A356 Alloy ◽  
Casting Process ◽  
Solid Particles ◽  
Filling Process ◽  
Die Casting Process ◽  
Defects Analysis ◽  
Semi Solid ◽  
Forming Defects

According to semi-solid slurry rheological behavior, an apparent viscosity model of A356 alloy developed based on the Carreau model was established to simulate filling process of rheo-diecasting about automobile shock absorber parts and to compare with conventional liquid filling process. Numerical simulation results showed that the filling process of rheo-diecasting was smooth but difficult to splash, which reduced the tendency of the alloy oxidation and inclusion. Meanwhile, a certain percentage of the primary solid particles precipitated before filling and solidification shrinkage of semi-solid slurry were small. This benefited to reduce or eliminate shrinkage defects of the castings. Compared with conventional liquid die casting process, rheo-diecasting process had unique advantages in reducing the internal defects and improving mechanical properties of castings.

Numerical Simulation of Semi-Solid Die Casting of ZA Alloy Automotive Bushing Based on AnyCasting

2013 ◽  
Vol 411-414 ◽  
pp. 3064-3067 ◽  
Author(s):  
Han Wu Liu ◽  
Zhi Ping Zhang ◽  
Yan Fang Luo ◽  
Li Lu
Keyword(s):  
Heat Dissipation ◽  
Die Casting ◽  
Solidification Process ◽  
Casting Process ◽  
Filling Sequence ◽  
Gas Trapping ◽  
Simulation Results ◽  
Stress And Deformation ◽  
Semi Solid ◽  
Solid Liquid

In order to reduce the wear of parts caused by long-term friction, and to reduce the frequency of parts replacement, ZA alloy with low hardness and good wear resistance is chosen to replace the traditional copper alloy as the material to manufacture automotive bushing, and the semi-solid die casting is used. On this basis, the software AnyCasting is used to simulate and analyze the filling and solidification process, the filling sequence, the variation of temperature field, and the part region where defects are prone to occur in the semi-solid process. The simulation results show that under the parameters set in the simulation process, when casting filling rate reached 90%, the metal started to solidify; since the gate place is easy for heat dissipation, when the temperature of the alloy liquid reached its liquidus temperature 595°C, the phenomenon of solid-liquid phase separation appeared at the gate; the defects such as gas trapping, residual stress and deformation would appear both in the place of first filling and the parting surface; when the preheat temperature of the mold was 150°C-200°C,the alloy liquid possesses liquidity. The simulation results offer certain theoretical instruction to optimize the semi-solid casting process of ZA Alloy automotive bushing manufacturing, as well as reducing or avoiding a variety of quality defects arose in the actual casting process.

Multiphase modelling of the transient flow for Sn-15Pb and 357.0 alloys in semi-solid die casting process

2020 ◽  
Vol 278 ◽  
pp. 116534
Author(s):  
Wenying Qu ◽  
Daquan Li ◽  
Fan Zhang ◽  
Min Luo ◽  
Xiaogang Hu ◽  
...  
Keyword(s):  
Transient Flow ◽  
Die Casting ◽  
Casting Process ◽  
Die Casting Process ◽  
Semi Solid

Tensile Properties of Semi-Solid Die Cast AC4C Aluminum Alloy

2014 ◽  
Vol 680 ◽  
pp. 11-14
Author(s):  
Ke Ren Shi ◽  
Sirikul Wisutmethangoon ◽  
Jessada Wannasin ◽  
Thawatchai Plookphol
Keyword(s):  
Heat Treatment ◽  
Tensile Strength ◽  
Aluminum Alloy ◽  
Die Casting ◽  
Casting Process ◽  
Al Alloy ◽  
Die Cast ◽  
Die Casting Process ◽  
Semi Solid ◽  
Strength And Ductility

In this study, semi-solid Al-Mg-Si alloy (AC4C) was produced by using the Gas Induced Semi-Solid (GISS) die casting process. The tensile strength and ductility of the semi-solid die cast Al alloy (GISS-DC) after T6 heat treatment were investigated and compared with those of the conventional liquid die casting (CLDC). The microstructures of GISS-DC and CLDC observed by an optical microscopy were presented. The ultimate tensile strength (UTS) and yield strength (0.2% YS) of GISS-DC are compatible with those of the CLDC. However, the GISS-DC has better ductility than the CLDC, this may be due to the smaller and more globular primary α-Al phase and rounder shaped-Si particle microstructures presented in the GISS-DC. Common shrinkage pores and defects were also observed by SEM from the fracture surfaces of both alloys.

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