scholarly journals Experimental and numerical investigations of oxide-related defects in Al alloy gravity die castings

2021 ◽  
Author(s):  
Giulia Scampone ◽  
Raul Pirovano ◽  
Stefano Mascetti ◽  
Giulio Timelli
Keyword(s):  
Fluid Dynamic ◽  
Casting Process ◽  
Numerical Code ◽  
Al Alloy ◽  
Numerical Investigations ◽  
Die Casting Process ◽  
Experimental Findings ◽  
Die Castings ◽  
Filling And Solidification ◽  
Image Analysis Techniques

AbstractThis research aimed to study the formation and distribution of oxide-related defects in the gravity die casting process of an AlSi7Cu0.5Mg alloy by using experimental and numerical investigations. Metallographic and image analysis techniques were conducted to map the distribution of oxide inclusions inside the casting at the microscopic level. Numerical simulations were used to analyse the filling and solidification stages, and to foresee the turbulence of the melt and the formation of the oxide defects. The results show that most of the defects were correlated with the oxide layers or bubbles entrained inside the liquid metal. The accuracy of the numerical code in simulating the metal fluid-dynamic behaviour and the heat transfer was verified, and the results were in agreement with the experimental findings. The numerical distribution of defects was consistent with the experimental results, proving that the model successfully predicted the formation of oxide-related defects.

Study on Pressure Variations in the Mold of Magnesium Alloy Die Castings

2007 ◽  
Vol 353-358 ◽  
pp. 1614-1616
Author(s):  
Yan Gai Liu ◽  
Zhao Hui Huang ◽  
Hao Ding ◽  
Ming Hao Fang ◽  
Shou Mei Xiong
Keyword(s):  
Magnesium Alloy ◽  
Real Time ◽  
Time Pressure ◽  
Die Casting ◽  
Solidification Process ◽  
Casting Process ◽  
Mold Filling ◽  
Die Casting Process ◽  
Die Castings ◽  
Filling And Solidification

High pressure die casting is the most common method in making magnesium alloys for both auto parts and 3C products. Pressure variations in the mold during mold filling and solidification process have direct influences on the quality and properties of die castings. In this paper, a cylinder head cover was produced to experimentally study pressure variations in the mold during magnesium alloy die-casting process in real time for the first time. Pressure varies at different positions in the mold during die casting process. This study indicates that mold filling and solidification process of magnesium alloy die castings can be described by pressure curves obtained by pressure measurement at different test positions in the cavity in real time.

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.

Floating Behavior of Entrapped Gas in Semi-Solid Metal

2017 ◽  
Vol 898 ◽  
pp. 1254-1260
Author(s):  
Hong Xing Lu ◽  
Qiang Zhu ◽  
Da Quan Li ◽  
Fan Zhang
Keyword(s):  
Solution Heat Treatment ◽  
Die Casting ◽  
Casting Process ◽  
Acceptance Rate ◽  
Solid Metal ◽  
High Quality ◽  
Casting Technology ◽  
Die Casting Process ◽  
Semi Solid ◽  
Die Castings

Semi-solid die casting technology has great advantages at defects control and has been successfully used to produce high quality aluminum alloy components for several years. In this process, semi-solid metal with high apparent viscosity and low plunger velocity are used to avoid surface turbulence which is the main source of entrapped gas in conventional die casting processes. But, entrapped gas still has other sources, such as melting, pouring, surface flooding and confluence weld. Solution heat treatment is always used to strengthen semi-solid die castings. The entrapped gas leads to blister defects, which directly decreases the acceptance rate of semi-solid die castings. So, the entrapped gas is still a serious issue in semi-solid die casting process. We studied the floating behavior of entrapped gas bubble in semi-solid metal. Two floating models were established for gas bubbles with different sizes. These models were used to analyze the possibility of entrapped gas escaping from semi-solid metal in casting practice. The results showed that entrapped gas from feed billet could not escape from the semi-solid metal in the casting process of impeller, which was proved by experiment results. These results emphasized the importance of clean melt and semi-solid metal. Some advices were given at last for avoiding or removing the entrapped gas in semi-solid die casting process.

On the Microstructure and Impact Properties of Slow Injection A356 Die Castings with Local Pressurization

2009 ◽  
Vol 628-629 ◽  
pp. 587-592
Author(s):  
Yan Fei Bai ◽  
Hai Dong Zhao ◽  
Yuan Yuan Li ◽  
Zhi Xin Kang
Keyword(s):  
Die Casting ◽  
Casting Process ◽  
Fracture Mechanisms ◽  
Absorbed Energy ◽  
Impact Properties ◽  
Die Casting Process ◽  
Die Castings ◽  
Pressure Die Casting ◽  
The Impact ◽  
Slow Injection

Microstructure and impact properties of slow injection A356 die castings with local pressurization have been investigated. The microstructure in the casting different regions were analyzed and compared. The casting impact absorbed energy varies from 1.17 to 2.35J, and is higher than that of other pressure die casting process. Furthermore, fracture mechanisms of different regions in castings are discussed. The results show that, the impact absorbed energy decreases with increase in SDAS. Also significant fluctuations of the impact properties in the thick-walled and local pressurization regions are found.

Investigations of the High Vacuum Die Castings of Dumbbell Specimens

2009 ◽  
Vol 628-629 ◽  
pp. 727-734
Author(s):  
Rong Yuan Jou
Keyword(s):  
Die Casting ◽  
High Vacuum ◽  
Testing Machine ◽  
Casting Process ◽  
Process Use ◽  
Vacuum Die Casting ◽  
Small Feature ◽  
Visualization Experiments ◽  
Die Casting Process ◽  
Die Castings

Compare to atmosphere die casting or moderate vacuum die casting process, use of the high vacuum die casting can enhance excluding gas volumes in the mold, improve the casting mechanical properties and density, and increase the fabrication feasibility for casting small feature size, shape, and higher quality of product. The process of high vacuum die casting for dumbbell specimens is established and implemented for evaluation of this innovative manufacturing technology. A transparent acrylic mold is fabricated to investigate the vacuum injection for vacuum die casting process and a metal mold is fabricated to test the real manufacturing of high vacuum die casting. To visualize the flowing pattern inside the mold under the consequence of evacuation processing, flow visualization experiments are conducted. Then, the specimen is molded by the high vacuum die casting process and the specimen castings are test by a universal testing machine for its loading-elongation relationship. The porosities of specimen casting are examined by scale weighting and direct visual inspection ways. Experimental results show that the high vacuum die casting process is effective to reduce the porosity (5.47% increment in weight) and to increase the strength (4.83% increment in maximum stress) of the investigated specimen. An obviously vortex roll is established along the centerline position of dumbbell specimen which may be became the source of porosity in real processing. Meanwhile, an excellent vacuum sealing is critical to the success of high vacuum die casting.

Numerical Simulation and Die Casting Process for Cylinder

2012 ◽  
Vol 490-495 ◽  
pp. 2362-2365
Author(s):  
Yong Huang ◽  
Yue Dong ◽  
Xiao Ming Du
Keyword(s):  
Numerical Simulation ◽  
Aluminum Alloy ◽  
Temperature Field ◽  
Die Casting ◽  
Casting Process ◽  
Processing Parameters ◽  
Mould Temperature ◽  
Pouring Temperature ◽  
Die Casting Process ◽  
Filling And Solidification

Filling and solidification for aluminum alloy packing block in die casting were simulated by numerical simulation. Distribution and change of temperature field as well as velocity field were visualized. The desirable processing parameters can be obtained with pouring temperature of 620°C and mould temperature of 180°C as well as shot velocity of 4m/s. The qualified products were obtained on the basis of the optimized die-casting parameters.

Numerical Simulation and Process Optimization of Aluminum Alloy Connecting Rod Based on ProCAST

2013 ◽  
Vol 712-715 ◽  
pp. 549-552
Author(s):  
Hua Feng Lu ◽  
Rong Fa Chen ◽  
Yi Hong Zhao ◽  
Long Wu ◽  
Zhi Long Li ◽  
...  
Keyword(s):  
Aluminum Alloy ◽  
Die Casting ◽  
Casting Process ◽  
Casting Defects ◽  
Permanent Mold ◽  
Connecting Rod ◽  
Technical Requirements ◽  
Simulation Results ◽  
Die Casting Process ◽  
Filling And Solidification

The structural feature and technical indexes of 2A14 aluminum alloy connecting rod was analyzed. The pouring system of gravity die-casting process was initially designed according to the technical requirements. The gravity filling and solidification stages in the permanent mold were simulated by ProCAST. The simulation results show that the casting defects are predicted and the casting process are improved. The most possible section of crack defects are the transition part between the shaft and the connecting rod small or big end.

Increase Pressure and Homogeneity of Die Castings from EN AC 47100 Alloy

2015 ◽  
Vol 729 ◽  
pp. 108-113
Author(s):  
Stefan Gaspar ◽  
Jan Pasko
Keyword(s):  
Die Casting ◽  
Casting Process ◽  
Internal Quality ◽  
Control Methods ◽  
Technological Factors ◽  
Great Reliability ◽  
Die Casting Process ◽  
Die Castings ◽  
Pressure Die Casting

In the pressure die casting process, a great attention is paid to a die castings quality improvement. This quality has to be ensured with a great reliability and, at the same time, it is necessary to apply control methods to a technological process which provide a complete picture of a die casting process as well as internal quality of the produced die castings. It requires control of the present technological factors of a pressure die casting process. The contribution deals with the effect of die casting plunger velocity inside a filling chamber on mechanical properties of a die casting product from EN AC 47100 alloy.

Effects of Die Temperature of SSS Die Casting on the Microstructure and Mechanical Properties of ADC12 Aluminum Alloy

2010 ◽  
Vol 97-101 ◽  
pp. 932-936
Author(s):  
Lian Qing Ji ◽  
Jian Min Shao ◽  
Guo Quan Xiang ◽  
Li Qian
Keyword(s):  
Mechanical Properties ◽  
Aluminum Alloy ◽  
Die Casting ◽  
Casting Process ◽  
Best Value ◽  
Die Temperature ◽  
Die Casting Process ◽  
Die Castings ◽  
Herringbone Structure ◽  
Hardened Surface

In the present paper, the effects of different die temperatures on microstructures and mechanical properties of aluminum alloy ADC12 at Super Slow Speed (SSS) die casting have been investigated, in order to optimize the die-casting process and its parameters. The results show that under SSS experimental condition, the density of castings is higher than that of general die castings. Die temperature has the best value, when the die temperature is 150 °C, smaller dendrites are distributed in the hardened surface layer, and the eutectics structure of and Si changes from needle-like structure into herringbone structure. The properties of the die casting are significantly influenced by the die temperature, the optimum die temperature is 150 °C.

scholarly journals Mechanical Properties of Al Matrix Composite Enhanced by In Situ Formed SiC, MgAl2O4, and MgO via Casting Process

Materials ◽  
2021 ◽  
Vol 14 (7) ◽  
pp. 1767
Author(s):  
Yuhong Jiao ◽  
Jianfeng Zhu ◽  
Xuelin Li ◽  
Chunjie Shi ◽  
Bo Lu ◽  
...  
Keyword(s):  
Mechanical Properties ◽  
Matrix Composite ◽  
Compression Strength ◽  
Casting Process ◽  
Al Alloy ◽  
Pyrolysis Process ◽  
Alloy Matrix ◽  
Al Matrix Composite ◽  
Al Matrix

Al matrix composite, reinforced with the in situ synthesized 3C–SiC, MgAl2O4, and MgO grains, was produced via the casting process using phenolic resin pyrolysis products in flash mode. The contents and microstructure of the composites’ fracture characteristics were analyzed by X-ray diffraction (XRD) and scanning electron microscopy (SEM). Mechanical properties were tested by universal testing machine. Owing to the strong propulsion formed in turbulent flow in the pyrolysis process, nano-ceramic grains were formed in the resin pyrolysis process and simultaneously were homogeneously scattered in the alloy matrix. Thermodynamic calculation supported that the gas products, as carbon and oxygen sources, had a different chemical activity on in situ growth. In addition, ceramic (3C–SiC, MgAl2O4, and MgO) grains have discrepant contents. Resin pyrolysis in the molten alloy decreased oxide slag but increased pores in the alloy matrix. Tensile strength (142.6 ± 3.5 MPa) had no change due to the cooperative action of increased pores and fine grains; the bending and compression strength was increasing under increased contents of ceramic grains; the maximum bending strength was 378.2 MPa in 1.5% resin-added samples; and the maximum compression strength was 299.4 MPa. Lath-shaped Si was the primary effect factor of mechanical properties. The failure mechanism was controlled by transcrystalline rupture mechanism. We explain that the effects of the ceramic grains formed in the hot process at the condition of the resin exist in mold or other accessory materials. Meanwhile, a novel ceramic-reinforced Al matrix was provided. The organic gas was an excellent source of carbon, nitrogen, and oxygen to in situ ceramic grains in Al alloy.

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