scholarly journals Non isothermal simulation of non-Newtonian flow in the shot sleeve of semi-solid die casting processes

PAMM ◽  
2012 ◽  
Vol 12 (1) ◽  
pp. 481-482
Author(s):  
Roudouane Laouar ◽  
Olaf Wünsch
Keyword(s):  
Die Casting ◽  
Shot Sleeve ◽  
Newtonian Flow ◽  
Semi Solid

Controlling and Minimizing Blistering during T6 Heat Treating of Semi-Solid Castings

2016 ◽  
Vol 256 ◽  
pp. 192-198 ◽  
Author(s):  
Hong Xing Lu ◽  
You Feng He ◽  
Stephen Midson ◽  
Da Quan Li ◽  
Qiang Zhu
Keyword(s):  
Solution Heat Treatment ◽  
Elevated Temperatures ◽  
Die Casting ◽  
Heat Treating ◽  
Pressure Casting ◽  
Shot Sleeve ◽  
Semi Solid ◽  
Entrapped Air ◽  
The Impact ◽  
Subsurface Defects

Surface blistering during T6 heat treating is an artifact that is essentially unique to high pressure casting processes such as semi-solid casting and die casting. It is believed that the blistering originates from subsurface defects present in the castings. When the castings are exposed to elevated temperatures during solution heat treatment, the strength of the aluminum is reduced, and the defects expand to deform the surfaces of the castings. There are three potential sources for the subsurface defects - entrapped air, die lubricant or shot sleeve lubricant.This paper will report on a study to determine the origin of the defects present in the castings that produce the blisters. Along with attempting to separate the influence of air and the two types of lubricants on blister formation, the study will also examine the impact of a number of process parameters on blistering.

Development of the Gas Induced Semi-Solid Metal Process for Aluminum Die Casting Applications

2008 ◽  
Vol 141-143 ◽  
pp. 97-102 ◽  
Author(s):  
J. Wannasin ◽  
S. Junudom ◽  
T. Rattanochaikul ◽  
M.C. Flemings
Keyword(s):  
Solid Fraction ◽  
Die Casting ◽  
Casting Machine ◽  
Gas Bubbles ◽  
Solid Metal ◽  
Heat Extraction ◽  
Shot Sleeve ◽  
Semi Solid

A simple and efficient rheocasting process that has recently been invented is being developed for aluminum die casting applications. The process called Gas Induced Semi-Solid (GISS) utilizes the combination of local rapid heat extraction and agitation achieved by the injection of fine gas bubbles through a graphite diffuser to create semi-solid slurry. In the GISS process, the die casting machine and the process cycle remain little changed from those of conventional die casting. The GISS unit creates a low solid fraction of semi-solid slurry in the ladle during the ladle transfer to the shot sleeve. The semi-solid slurry is then poured directly into the shot sleeve. This paper presents the detailed description of the process. The results of the semi-solid die casting experiments with ADC10 alloy using the GISS process are also reported and discussed.

scholarly journals Industrial Semi-Solid Rheocasting of Aluminum A356 Brake Calipers

2011 ◽  
Vol 2011 ◽  
pp. 1-5 ◽  
Author(s):  
U. A. Curle ◽  
J. D. Wilkins ◽  
G. Govender
Keyword(s):  
Die Casting ◽  
Casting Process ◽  
Shot Sleeve ◽  
Process Stability ◽  
X Ray ◽  
Initial Stage ◽  
Heat Treated ◽  
Die Casting Process ◽  
Semi Solid ◽  
Pressure Die Casting

Industrial semi-solid casting trials of aluminum A356 brake calipers were performed over five days with the CSIR-RCS and high-pressure die casting process cell. Consecutive visual passed castings were used as the measure of process stability, and common defects between trials were categorized. Short fill results are erratic and caused by unintended underdosing by the furnace or incomplete billet discharge at the delivery point in the shot sleeve. Cold shuts can be significantly reduced by adjusting the shot control profile. Surface finish defects include surface roughness and staining caused by lubricant burn off. Visual passed castings display none of the above-mentioned external defects. X-ray examination and pressure testing of heat-treated castings from the consecutive visual passed castings show improvement over the five days. These initial-stage industrialization efforts pave the way for process commercialization.

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.

Application of Automobile Lightweight Alloys and the Development of its Die-Casting Technology

2011 ◽  
Vol 308-310 ◽  
pp. 785-789 ◽  
Author(s):  
De Fang Liu ◽  
Jie Tao
Keyword(s):  
Automotive Industry ◽  
Die Casting ◽  
Low Pressure ◽  
Development Trend ◽  
Casting Technology ◽  
Low Pressure Die Casting ◽  
Lightweight Alloys ◽  
Semi Solid ◽  
Pressure Die Casting ◽  
The Development Trend

With the development of lightweight vehicles, lightweight alloy materials has been increasingly used in automotive industry, automobile manufacturers are therefore looking for thinner and stronger materials so that the higher requirements has became a challenge to lightweight alloy die-casting technology. The paper summarized the applications of lightweight alloys in the automotive industry, and the new advances of lightweight alloys die-casting technology, such as low pressure die-casting, semi-solid die casting, oxygenation die-casting and the combination of different die-casting technologies, and discussed the development trend of the lightweight alloy die-casting technology.

Microstructure Evolution and Mechanical Properties of Rheoformed YL112 Aluminum Alloy

2008 ◽  
Vol 141-143 ◽  
pp. 163-168 ◽  
Author(s):  
Xiang Jie Yang ◽  
Hong Min Guo
Keyword(s):  
Mechanical Properties ◽  
Aluminum Alloy ◽  
Shape Factor ◽  
Die Casting ◽  
Equivalent Diameter ◽  
Uniform Microstructure ◽  
Casting Aluminum Alloy ◽  
Casting Aluminum ◽  
Semi Solid ◽  
Secondary Solidification

Rheo-die casting (RDC) based on LSPSF (low superheat pouring with a shear field) rheocasting process has been exploited. In case of secondary die casting aluminum alloy YL112, LSPSF allowed for preparation of sound semi-solid slurry in 15-20s that fully meet the production rate of HPDC, the primary α-Al exhibiting a mean equivalent diameter of 70 μm and shape factor of 0.93, without any entrapped eutectic. Compared to conventional HPDC, RDC improves microstructures in castings. Secondary solidification of semi-solid slurry takes place uniformly throughout the entire cavity, producing an extremely fine and uniform microstructure. The experimental results show the RDC 380 alloy has much improved integrity and mechanical properties, particularly elongation, and heat treatment can be used to enhance the mechanical properties.

Study on Rheo-Diecasting for In Situ Synthesized Mg2Si/AM60 Composites

2011 ◽  
Vol 383-390 ◽  
pp. 707-711
Author(s):  
Hong Yan ◽  
Yong Hu ◽  
Xiao Quan Wu
Keyword(s):  
Die Casting ◽  
Casting Machine ◽  
Chinese Script ◽  
Matrix Composites ◽  
Forming Process ◽  
Magnesium Matrix ◽  
Magnesium Matrix Composites ◽  
Mechanical Stirring ◽  
Semi Solid

Magnesium alloys have high specific strength, specific stiffness, excellent thermal conductivity and casting properties, which have a great prospects development in the industry, However, its low plasticity and ductility limited its application. Magnesium matrix composites can effectively improve its performance. Magnesium alloy die-casting is the main forming process, the conventional high-pressure die-casting (HPDC) defects in multi-cavity type, easy to volume gas, non-heat-treated. Compared with HPDC, the rheo-diecasting (RDC) process has been greatly developed for near-net shape components. In this paper, Mg2Si /AM60 composites is fabricated by in-situ synthesis and semi-solid magnesium matrix composites which are rheoformed in the die-casting machine are prepared by mechanical stirring. The results indicate that the microstructure of composites is non-dendritic and Chinese script type Mg2Si are fine distributed. The fundamental morphology of microstructure by HPDC is dendrite and liquid-phase distributed between dendrite irregularly. The RDC samples have close-to-zero porosity, less segregation, the most of semi-solid of microstructure in rheo-diecasting is spherical or as-spherical structure.

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.

Slurry Preparation and Hot Tearing Susceptibility of A201 Aluminum Alloy in Rheological Die Casting

2019 ◽  
Vol 285 ◽  
pp. 311-317 ◽  
Author(s):  
Jun Zhen Gao ◽  
Qiang Zhu ◽  
Da Quan Li ◽  
Xiao Gang Hu ◽  
Min Luo ◽  
...  
Keyword(s):  
Aluminum Alloy ◽  
Die Casting ◽  
Mold Temperature ◽  
Hot Tearing ◽  
Cast Aluminum Alloy ◽  
Cast Aluminum ◽  
Intensification Pressure ◽  
Semi Solid ◽  
Index Value ◽  
Hot Tearing Susceptibility

A201 alloy is the strongest cast aluminum alloy, but it is considered one of the most difficult aluminum alloys to cast due to its susceptibility to hot tearing during solidification. Semi-solid casting, which characterizes fine near-globular or non-dendritic grains and relatively narrow solidification range, is potential to reduce hot cracking tendency of alloys. In this present work, semi-solid slurries of A201 alloy were prepared using Swirled Enthalpy Equilibrium Device (SEED) technique and then injected into a self-designed high pressure hot tearing mold. The microstructures of A201 semi-solid slurries with different pouring temperatures were examined. Effects of different casting pressures on the hot tearing sensitivity of A201 have been investigated. This study finds that SEED is capable of producing satisfying A201 semi-solid slurries. Lower pouring temperatures produce A201 semi-solid slurries with finer and rounder grains as well as more uniform microstructure distribution. Increasing the intensification pressure significantly decreases the hot treating tendency of A201 alloy. When the pressure reaches to 90 MPa and the mold temperature of about 250 °C, the hot tearing susceptibility (HTS) index value is nearly zero, which means almost no surface cracks are found in the semi-solid A201 die casting parts.

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