Sub Liquidus Casting Technology for the Production of High Integrity Component

2008 ◽  
Vol 141-143 ◽  
pp. 219-224 ◽  
Author(s):  
Antonio Forn ◽  
Sergi Menargues ◽  
Enric Martín ◽  
Josep A. Picas

This work is a contribution to improve the knowledge of components behavior produced by semi-solid processes particularly the Sub-Liquidus-Casting process. Die design was supported by using the Procast simulation program. The effect of the different variables of the process in structural integrity of the product has been described and analyzed. The components were produced using A356 alloy formed on a pilot plant with a 400 Ton THT press. The components study was made by RX, metallographic analysis and mechanical tests. The effects of T5 and T6 heat treatments were also studied.

2006 ◽  
Vol 116-117 ◽  
pp. 501-504 ◽  
Author(s):  
Gonasagren Govender ◽  
L. Ivanchev ◽  
N. Jahajeeah ◽  
R Bëan

The Council for Science and Industrial Research has developed and patented a rheocasting process. The process involves the preparation of semi-solid slurries from liquid metal, by controlled cooling and MHD stirring using induction coils. An industrial prototype was designed and built to test the system in an industrial environment. A semi-solid high pressure die casting cell was set up with an industrial partner and the system was tested under normal production conditions. The production cell consisted of the CSIR rheocasting system, a six axis robot, dosing furnace and 400 ton H-400SC shot controlled Bühler HPDC machine. An engine mounting bracket originally designed for liquid HPDC was redesigned for SSM forming (casting) taking into consideration the flow and thermal behaviour of semi-solid casting process, the function of the component and the required mechanical properties. Although a full production run was not completed due to an ancillary equipment failure, sufficient castings were produced to perform preliminary evaluation of the components. The processing parameters used were, die temperature of 250°C, SSM casting temperature of 580°C ±1Cº and a piston injection velocity of 0.13 m/s. Initial evaluation showed evidence of casting defects due to a combination of factors: die design/manufacture, casting parameters and poor foundry practice. From the mechanical tests it was evident that if the die design, casting parameters and foundry practice are optimized components with adequate mechanical properties can be reliably produced.


2016 ◽  
Vol 256 ◽  
pp. 334-339 ◽  
Author(s):  
Song Chen ◽  
Fan Zhang ◽  
You Feng He ◽  
Da Quan Li ◽  
Qiang Zhu

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.


2019 ◽  
Vol 285 ◽  
pp. 429-435 ◽  
Author(s):  
Song Chen ◽  
Da Quan Li ◽  
Fan Zhang ◽  
Min Luo ◽  
Xiao Kang Liang ◽  
...  

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.


2012 ◽  
Vol 192-193 ◽  
pp. 293-298 ◽  
Author(s):  
Fan Zhang ◽  
Nan Nan Song ◽  
Jun Zhang ◽  
Yong Lin Kang ◽  
Qiang Zhu

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.


2017 ◽  
Vol 898 ◽  
pp. 1254-1260
Author(s):  
Hong Xing Lu ◽  
Qiang Zhu ◽  
Da Quan Li ◽  
Fan Zhang

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.


2011 ◽  
Vol 474-476 ◽  
pp. 255-259 ◽  
Author(s):  
Ya Ping Hu ◽  
Yong Hu

Numerical simulation can be used to predict die filling, and hence to optimize the die design. In the study, the flow characteristics of liquid filling comparing with those of semi-solid filling were analyzed. The results indicated that the liquid filling turned out to be turbulent, while the semi-sold filling had laminar flow characteristics which could reduce the foundry defects such as gas cavity and oxidation mixture. The distribution of pressure reduced gradually in the filling direction during semi-solid filling process which would generate back pressure that was favorable for filling process.


2005 ◽  
Vol 475-479 ◽  
pp. 2533-2538 ◽  
Author(s):  
Chung Gil Kang ◽  
P.K. Seo ◽  
Byung Min Kim

Die design rule for semi-solid die casting (SSDC) with A356 electromagnetic stirring (EMS) aluminum alloy, was proposed. The die design rule included inspection of machine, part requirements, parting line determination, sleeve, plunger, gating system, overflow, air vent, ejector pin, and heating line design. The specification of gating system, overflow, air vent, plunger tip, and sleeve suitable for respective part were regulated. Two steps die system of lower-positioned gate and three steps die system of center-positioned gate were manufactured for 4 automobile suspension parts, based on the die design rule. For the sound filling pattern and solidification behavior, injection speeds of 4 parts were summarized to the interval (from V1 to V4). As a result of observing the microstructure of 4 parts after T6 heat treatment, primary Al-α phase was globularized and fine Si particles were distributed around the grain boundary. The mechanical properties of 4 parts with T6 heat treatment were investigated and showed ultimate tensile strength (UTS) of 330 MPa, yield strength (YS) of 250 MPa, and elongation of 7.5% as average.


2016 ◽  
Vol 850 ◽  
pp. 642-648 ◽  
Author(s):  
Song Chen ◽  
Da Quan Li ◽  
Fan Zhang ◽  
You Feng He ◽  
Qiang Zhu ◽  
...  

Compared with traditional liquid and solid processing methods, semi-solid die casting process can apparently overcome shrinkage cavity and porosity defects in castings and high deformation resistance and high residual stress shortcomings in forging parts. Semi-solid die casting process with advantages such as high efficiency and low cost, will become the optimal process for high quality automobile parts. In this study, using the clamp as an example, the author introduced product structure optimization and die design for semi-solid die-casting process of aluminum alloy in a new product development.The Computer Aided Engineering technology was applied to the product structure optimization according to the stress analysis. The optimal mold structure, including cavity layout, gating system, overflow and vent systems, were confirmed based on the die design criteria for traditional die casting, combining with the characteristics of semi-solid forming and the simulation results. The semi-solid aluminum alloy clamp parts with excellent performances were finally developed successfully by means of product structure optimization, die design, parameters optimization of die casting process, and the mechanical properties test of products.The existing parts were optimized to make them more suitable for semi-solid die casting processing. In addition, a reasonable die design specially for semi solid processing was an important guarantee for a successful semi solid product applied in industry. Computer numerical simulation was applied in product structure design for semi-solid die casting, die design, die-casting process optimization and other aspects, to shorten the development cycle of new product, reduce cost and improve efficiency.


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