Processing of Hypereutectic AlSiCuFe Alloys in the Semi-Solid State

2008 ◽  
Vol 141-143 ◽  
pp. 587-592 ◽  
Author(s):  
Yücel Birol
Keyword(s):  
Solid State ◽  
Die Casting ◽  
Casting Process ◽  
Wear Resistant ◽  
Heat Treated ◽  
Die Cast ◽  
Semi Solid ◽  
Low Superheat

Hypereutectic Al-Si based alloys are expected to be more wear resistant than the AlSi8Cu3Fe alloy, currently used in compressor connecting rods in die cast grades. Die casting of such alloys, however, is not straightforward. Semi-solid processing was thus considered to overcome the problems encountered in casting hypereutectic Al-Si alloys. Two experimental hypereutectic AlSiCuFe alloys were obtained by adding 8 to 12 wt% Si to the AlSi8Cu3Fe alloy. The ingots of these alloys were melted and cooled to very near their liquidus points, 625°C and 675°C respectively, before they were poured into a permanent mould in order to produce nondendritic feedstock for thixoforming. This low superheat casting process largely replaced α-Al dendrites with relatively smaller α-Al rosettes. The slugs machined from the ingots thus obtained were thixoformed after they were heated in situ in the semi-solid range for 5 minutes in a laboratory press. Several thixoformed parts were heat treated to the T6 temper with an accompanying increase in hardness from 91-96 HB to 130-131 HB.

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.

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.

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.

Fluxless Recycling of Die-Cast AZ91 Magnesium Alloy Scrap

2005 ◽  
Vol 475-479 ◽  
pp. 541-544 ◽  
Author(s):  
Hwa Chul Jung ◽  
Young Cheol Lee ◽  
Kwang Seon Shin
Keyword(s):  
Mechanical Properties ◽  
Magnesium Alloy ◽  
Die Casting ◽  
Casting Process ◽  
Az91 Alloy ◽  
Main Concern ◽  
Az91 Magnesium Alloy ◽  
Die Cast ◽  
Class 1 ◽  
High Level

Magnesium die-casting has experienced dramatic growth over the past decade and the recycling of magnesium scrap has become increasingly important due to the generation of substantial quantities of scrap in the die-casting process. Magnesium is a readily recyclable material and the recycling of magnesium scrap is crucial in making magnesium more competitive. The main concern associated with using the secondary magnesium is the high level of Fe content and oxide inclusions that are detrimental to the corrosion and mechanical properties of the secondary alloy. In this study, the die-cast specimens were produced using the recycled class 1 scrap which is refined by means of Ar bubbling and Mn addition without using refining fluxes, and their mechanical properties and corrosion characteristics were investigated. The results showed that the tensile properties of the secondary AZ91 alloy were equivalent to those of the primary magnesium alloy after appropriate treatments. The corrosion resistance of the recycled magnesium was also found to increase by Ar bubbling and Mn addition.

Comparison of Microstructure and Mechanical Properties of Semi-Solid Castings Produced Using Billets Made by EMS and SEED

2014 ◽  
Vol 217-218 ◽  
pp. 332-339 ◽  
Author(s):  
Xiao Kang Liang ◽  
Da Quan Li ◽  
Pascal Côté ◽  
Stephen P. Midson ◽  
Qiang Zhu
Keyword(s):  
Mechanical Properties ◽  
Cross Section ◽  
Dendritic Structure ◽  
Casting Process ◽  
Grain Structure ◽  
High Quality ◽  
Microstructure And Mechanical Properties ◽  
Grain Structures ◽  
Heat Treated ◽  
Semi Solid

The spheroidal grains in billets used for semi-solid casting are generally manufactured by electromagnetic stirring (EMS) during the casting process. This method however, is not economically applicable for small quantities of the thixo billets. Swirled Enthalpy Equilibration Device (SEED) has been developed as a rheocasting process, and the SEED process is of interest for developing new thixo alloys, as well as for optimizing the thixocasting processes for high quality components. The objective of this paper is to compare the microstructure and mechanical properties of aluminum alloy 319s billets and castings produced using EMS and SEED feed materials. The experimental results show that for as-cast billets made from SEED process, a well-developed spheroidal grain structure is distributed throughout the cross-section of the billet, while for as-cast EMS billets, the grain structure is inhomogeneous, i.e., a dendritic structure was present adjacent to the surface of the billet, while a uniform, spheroidal structure was present at the centre. After the thixocasting process, however, the both SEED and EMS billets have well-developed, spheroidal grain structures. Mechanical properties of thixocast and T61 heat treated components are comparable for the both SEED and EMS billets.

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.

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