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Die Casting Technology Develops Steadily

The 5th China International Die Casting Congress & Exhibition,

sponsored by the Chinese Mechanical Engineering Society

(CMES) and the China Productivity Promotion Center of

Machinery Industry; and organized by the Foundry Institution

of Chinese Mechanical Engineering Society (FICMES), Shenyang

University of Technology and Foundry Journal Agency, was

held in Shanghai, China, from June 28 to July 1, 2006. There

are 44 academic papers included in the proceedings of the

congress, which were chosen from a large number of papers

submitted, reflecting the development of China’s die casting

industry in the last two years.

1. Development of the Die Casting IndustryThe globalization of the world economy, demand for light

weight castings for automobile parts, and the sustainable

development of our country’s economy all promote the die

casting industry to transfer gradually from the developed

countries to the developing countries such as China. The

output of die castings in China in 2005 approached 9 x 105 t,

of which aluminum alloys exceeded 6.3 x 105 t, zinc alloy was

2.2 x 105 t, and magnesium alloy was nearly 0.1 x 105 t. The

production value of die castings in 2005 exceeded 40 million

yuan RMB, growing 10.9 % compared with last year.

In the die casting congress, Mr. SONG Cai-fei, a member of

the Die Casting Committee of the China Foundry Association,

presented an overview The Characteristics and Regularity ofThe Characteristics and Regularity ofThe Characteristics and Regularity ofThe Characteristics and Regularity ofThe Characteristics and Regularity of

Development on China’s Die Casting IndustryDevelopment on China’s Die Casting IndustryDevelopment on China’s Die Casting IndustryDevelopment on China’s Die Casting IndustryDevelopment on China’s Die Casting Industry covering several

aspects of the basic survey, the inevitability of continuous

development, diversity, etc. and giving the output of die

castings of varieties of nonferrous alloys in 2005 and their

share in the total output. The diversity of die casting

development in China was discussed in detail covering six

areas of die casting development - production of aluminum

alloy cylinder blocks for automobile engines, production of

aluminum alloy hubs and pistons, the continued increase in

output and sale of motorcycles, the large market for automobile

parts, real estate promoting the rapid development of the

hardware industry, and the output of die castings of magnesium

alloy growing 20% annually. Finally, the problems the die

casting operations facing in China were pointed out.

Mr. TANG Yu-lin, of the Productivity Promotion Center of

Foundry Industry of China, analyzed the development trends

of the die casting industry in China in his paper Making Light-Making Light-Making Light-Making Light-Making Light-

weight Automobiles Promotes the Development of Light Castingweight Automobiles Promotes the Development of Light Castingweight Automobiles Promotes the Development of Light Castingweight Automobiles Promotes the Development of Light Castingweight Automobiles Promotes the Development of Light Casting

Market.Market.Market.Market.Market. The amounts of aluminum used for sedan parts

(including engine, transmission case, hubs, suspension system

& frame, radiator, steering wheel, etc.) in North America,

Western Europe, and Asia in 2001 were compared. Several

proposals on the development of the die casting industry in

China and strengthening market competition were put forward.

Four aspects of the technical progress were pointed out: (1)

Optimization of the die casting process and development of

new alloy materials to adapt the development of automobile

die castings toward thin wall, complex shape, high strength,

and high quality; (2) Reduction of production costs from several

aspects such as integration of design, prolonging service life

of die, etc; (3) Popularization of computer simulation

techniques to shorten the development period of processes;

(4) The importance of the utilization of secondary aluminum

resources and the setting up of a comprehensive scrap recycling

system.

2. Die Casting and Semi-Solid Technology forAluminum Alloy

The die casting production for aluminum alloys still occupies

a very important position in China’s die casting industry and is

used extensively for automobiles, motorcycles, toys, and

hardware. Semi-solid processing, a new forming technique

suitable for preparing high quality parts is receiving more and

more attention. Its fundamental work and applied research

are being conducted in detailed depth.

In the paper Experimental Studies on Rheocasting ProcessingExperimental Studies on Rheocasting ProcessingExperimental Studies on Rheocasting ProcessingExperimental Studies on Rheocasting ProcessingExperimental Studies on Rheocasting Processing

of A356 Alloyof A356 Alloyof A356 Alloyof A356 Alloyof A356 Alloy presented by prof. TANG Jing-lin, of the

Department of Mechanical Engineering, Tsinghua University,

the author used the thin plate specimen with five steps and

rheocasting mould developed independently to study

experimentally a new rheoforming process with separate slurry

preparation systems and component shaping systems for A356

alloy. The results show that with the proper crucible structure

and coating composition, the semi-solid alloy slurry could be

smoothly transferred from the slurry preparation equipment

to the rheocasting shot chamber by the slurry preparation

crucible. Following the optimization of the rheocasting

processing parameters, the tensile strength and elongation of

samples could be increased by 11.6% - 18.2 % and 42.5% - 50 %

respectively, compared with the traditional liquid die casting

YUAN Xiao-guang1, HUANG Hong-jun1, LI Rong-de1, CAO Yang2, SU Shi-fang2

(1. Shenyang University of Technology, Shenyang 110023, Liaoning; 2. FICMES, Shenyang 110022, Liaoning)

Die Casting Technology Develops Steadily-- A Commentary on the 5th China International Die Casting Congress

Vol.3 No.4 Information

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ones. Also during the rheocasting process, the semi-solid alloy

slurries flow smoothly, and the microstructures of samples are

dense and free from pores, so that the samples have the

potential for strengthening by heat treatment.

In the study on Semi-Solid Forming Technology andSemi-Solid Forming Technology andSemi-Solid Forming Technology andSemi-Solid Forming Technology andSemi-Solid Forming Technology and

Properties of Al-Si-FeProperties of Al-Si-FeProperties of Al-Si-FeProperties of Al-Si-FeProperties of Al-Si-Fe by Dr. ZHAO Shu-guo, of Shenyang

University of Technology, the semi-solid forming technology

for hypoeutectic Al alloy was applied to hypereutectic Al alloy.

The results show that the second phase in the semi-solid formed

alloy became fine and spherical, and its distribution is

homogeneous. With the increasing of the extrusion ratio and

the decreasing of the forming temperature, the second phase

broken up increased and d is t r ibuted even more

homogeneously. So better mechanical properties and wear

resistance could be obtained. All these will provide technical

support for the application of the hypereutectic Al-Si alloy in

automobile industry.

Aluminum alloy hubs in a sedan are one of main parts by

light weight fabrication. Its fatigue property is an important

criterion in assessing its quality. In the paper Factors InfluencingFactors InfluencingFactors InfluencingFactors InfluencingFactors Influencing

Fatigue Life of Low Pressure Die Cast A356 Alloy WheelsFatigue Life of Low Pressure Die Cast A356 Alloy WheelsFatigue Life of Low Pressure Die Cast A356 Alloy WheelsFatigue Life of Low Pressure Die Cast A356 Alloy WheelsFatigue Life of Low Pressure Die Cast A356 Alloy Wheels by

engineer WU Han-qi of Dicastal Wheel Mfg. Co. Ltd, two

different kinds of bending fatigue cracks of low pressure cast

A356 alloy wheels were investigated. Their characteristics were

compared, forming reason as well as the effects of

microstructure and defects on the fatigue life of wheel were

analyzed using SEM. On the basis of the above, the measures

to increase the fatigue life are put forward from six aspects:

(1) Degassing for melt, (2) Optimizing the process parameters,

(3) Adopting a thermal isostatic pressure process, (4) Modifying

and fining for melt, (5) Controlling Fe content, (6) Proper heat

treatment. All these will have great instructive action in the

production of aluminum alloy hubs.

3. Die Casting and Semi-solid Technology forMagnesium Alloy

In recent years, the number of die casting enterprises and

science & research organizations engaging in magnesium alloy

production has increased rapidly from the original few to nearly

a hundred. Considering the availability of magnesium resource

in our country, it is hopeful that this research development

might become industrial reality.

The paper Study on Interfacial Heat Transfer CoefficientStudy on Interfacial Heat Transfer CoefficientStudy on Interfacial Heat Transfer CoefficientStudy on Interfacial Heat Transfer CoefficientStudy on Interfacial Heat Transfer Coefficient

between Metal/Die Interface of High Pressure Die Castingbetween Metal/Die Interface of High Pressure Die Castingbetween Metal/Die Interface of High Pressure Die Castingbetween Metal/Die Interface of High Pressure Die Castingbetween Metal/Die Interface of High Pressure Die Casting

Process of AZ91D AlloyProcess of AZ91D AlloyProcess of AZ91D AlloyProcess of AZ91D AlloyProcess of AZ91D Alloy presented by GUO Zhi-peng and

XIONG Shou-mei of the Key Lab. for Advanced Manufacturing

by Materials Processing Technology, Department of Mechanical

Engineering, Tsinghua Unversity, won the silver award of the

‘Wanfeng’ Cup for excellent foundry papers. In the paper the

temperature profiles inside the die were measured based on

high pressure die casting experiments using AZ91D magnesium

alloy. Using a computer program based on solving the inverse

heat problem, the metal/die interfacial heat transfer coefficient

(IHTC) was calculated and studied. The results indicated that

the IHTC between metal and die increases right after the liquid

metal is brought into the cavity by the plunger and decreases

as the solidification process of the liquid metal proceeds until

the liquid metal solidifies completely, when the IHTC tends to

be stable. The interfacial heat transfer coefficient shows

different characteristics under different casting wall thickness

and varies with the change of solidification behavior. This

will have a directive function to theoretical investigation for

the solidification processes of die castings.

High vacuum die casting is a valuable method for the

reduction of gas porosities of the die castings and removal of

air, gas and lubricant vapor from die cavity. Ryobi Limited has

developed the high quality die casting technology to mass-

production of the front sub-frame. This has achieved a 40 %

weight reduction for the front sub-frame in comparison with

the ordinary stamped steel products. At the congress, Mr.

Mamoru Murakami, of the Research and Development Division,

Ryobi Limited, Japan, introduced in detail the high quality die

casting technology. This technique has been used for the large

automobile safety die casting parts requiring high quality.

Mr. LONG Si-yuan of Chongqi Shuolong Science and

Technology Co. Ltd., introduced advanced melting and pouring

furnaces for magnesium alloys all over the world, and described

the effect of the characteristics of magnesium alloy melting

furnaces on its operation, melt quality, and production cost.

A comparison of the national and foreign furnaces was made

in technique, function, material, and economy. The results

show that the gap between our country and developed

countries for magnesium alloy melting furnaces is being

narrowed. Some techniques at home have reached the

international advanced level. This shows that the technology

in China has made a great progress.

In the paper Discussion on Thixocasting Processing ofDiscussion on Thixocasting Processing ofDiscussion on Thixocasting Processing ofDiscussion on Thixocasting Processing ofDiscussion on Thixocasting Processing of

Magnesium AlloysMagnesium AlloysMagnesium AlloysMagnesium AlloysMagnesium Alloys presented by Prof. YAN Feng-yun, of the

Key Lab. for Non-ferrous Metal Alloys, Ministry of Education,

Lanzhou University of Technology, the process and

technological parameters for thixocasting of magnesium alloys

were analyzed in detail by comparision with traditional die

casting technology. Combined with unique features of die

casting machinery, some valuable technological parameters

for thixocasting of magnesium alloys were given to offer

reference for researchers.

4. Progress of Squeeze Casting TechnologyAttention is still being paid to squeeze casting technology.

The paper Study on Bubbling in Heat Treatment Process ofStudy on Bubbling in Heat Treatment Process ofStudy on Bubbling in Heat Treatment Process ofStudy on Bubbling in Heat Treatment Process ofStudy on Bubbling in Heat Treatment Process of

Squeeze CastingSqueeze CastingSqueeze CastingSqueeze CastingSqueeze Casting presented by Mr. QI Pi-xiang, of Ningbo Sub-

academy of the National Weapons Science Research Academy,

won the silver award of the ‘Wanfeng’ Cup for excellent foundry

papers. In the paper, the author pointed out that bubbling is

one of the common defects in the heat treatment process of

squeeze casting, and it has relationships with squeeze mode,

technique, mould, etc. Therefore, for direct squeeze-casting

parts, solution heat treatment can be performed smoothly as

CHINA FOUNDRY Nov. 2006

324

long as oil-based paint is not used and air exhaust is well

arranged; for indirect squeeze casting parts, solution heat

treatment can also be applied when additional factors are taken

into consideration, including well designed internal feeding

system and strictly controlled liquid metal filling velocity to

prevent from inclusions.

The paper Influence of Squeeze Casting Parameters onInfluence of Squeeze Casting Parameters onInfluence of Squeeze Casting Parameters onInfluence of Squeeze Casting Parameters onInfluence of Squeeze Casting Parameters on

Microstructure and Mechanical Properties of Plunger Type ZA27Microstructure and Mechanical Properties of Plunger Type ZA27Microstructure and Mechanical Properties of Plunger Type ZA27Microstructure and Mechanical Properties of Plunger Type ZA27Microstructure and Mechanical Properties of Plunger Type ZA27

Alloy Castings with High Ratio of Height to ThicknessAlloy Castings with High Ratio of Height to ThicknessAlloy Castings with High Ratio of Height to ThicknessAlloy Castings with High Ratio of Height to ThicknessAlloy Castings with High Ratio of Height to Thickness, which

was presented by Prof. LI Rong-de of Shenyang University of

Technology, won the gold award of the ‘Wanfeng’ Cup for

excellent foundry papers. In the paper, the fundamental

problem of plunger type squeeze casting of ZA27 alloy, with

high ratio of height to thickness (M=H/D=7), was investigated.

The influence of the squeeze casting parameters on the

mechanical properties and microstructure of the ZA27 alloy

was analyzed. The plunger type squeeze casting parameters

best suited for ZA27 alloy, with high ratio of height to thickness,

were preliminary decided. Squeeze casting improves the

mechanical properties of ZA27 alloy and offers important

maintenance logistics for developing the applied range of ZA27

alloys.

In addition, Continuous Squeeze Casting Process By MassContinuous Squeeze Casting Process By MassContinuous Squeeze Casting Process By MassContinuous Squeeze Casting Process By MassContinuous Squeeze Casting Process By Mass

ProductionProductionProductionProductionProduction by Mr. YUN Xia, of SPX Contech, USA, and LatestLatestLatestLatestLatest

Development of Fabrication Technique for Ultra-Fine GrainedDevelopment of Fabrication Technique for Ultra-Fine GrainedDevelopment of Fabrication Technique for Ultra-Fine GrainedDevelopment of Fabrication Technique for Ultra-Fine GrainedDevelopment of Fabrication Technique for Ultra-Fine Grained

Mg alloysMg alloysMg alloysMg alloysMg alloys by CHEN Yong-jun, of Light Alloy Net Forming

National Engineering Research Center, Shanghai Jiaotong

University, both have great influence.

5. Application of Computer SimulationTechnology in Die Casting

In the last two years, domestic computer simulation technology

has been developed rapidly, especially for some simulation

softwares now commercially available. At present, more and

more enterprises are using it in the R & D of products. So the

theme of computer application in the congress is still an

important topic for discussion.

In the paper Application of KBE in HPDC OptimizationApplication of KBE in HPDC OptimizationApplication of KBE in HPDC OptimizationApplication of KBE in HPDC OptimizationApplication of KBE in HPDC Optimization by

Prof. WANG Guo-xiang, of Shanghai Jiaotong University, on

constructing the framework for the application of KBE in high

pressure die casting process and die design, the author created

the rules database, based on the rule-based reasoning

technology. It is beneficial to shorten the development period

of new high quality products.

In the paper Application of Numerical Simulation TechnologyApplication of Numerical Simulation TechnologyApplication of Numerical Simulation TechnologyApplication of Numerical Simulation TechnologyApplication of Numerical Simulation Technology

in Die Casting Processin Die Casting Processin Die Casting Processin Die Casting Processin Die Casting Process by Prof. LIAO Dun-ming, of the College

of Materials Science & Engineering, Huazhong University

Science and Technology, the author introduced the main

contents of numerical simulation of die casting process and

some applications of InteCast CAE Software in die casting die

design; and described its function in improving the rationality

and accuracy of structure for die casting dies.

In the paper Numerical Simulation on the Temperature FieldNumerical Simulation on the Temperature FieldNumerical Simulation on the Temperature FieldNumerical Simulation on the Temperature FieldNumerical Simulation on the Temperature Field

of Magnesium Alloy Die Casting Diesof Magnesium Alloy Die Casting Diesof Magnesium Alloy Die Casting Diesof Magnesium Alloy Die Casting Diesof Magnesium Alloy Die Casting Dies by Prof. YU Bao-yi, of

Shenyang University of Technology, the effects of the die

casting process, the variation of temperature field, and the

type of cooling on magnesium alloy automotive mantle were

calculated and analyzed by using Z-cast software. Based on

the results, reasonable process parameters and type of cooling

were pointed out for improving the service life of dies used

for magnesium alloy automotive mantle.

In addition, the papers Application of CASTsoft in LowApplication of CASTsoft in LowApplication of CASTsoft in LowApplication of CASTsoft in LowApplication of CASTsoft in Low

Pressure Casting ProcessPressure Casting ProcessPressure Casting ProcessPressure Casting ProcessPressure Casting Process by ZHANG Zheng, of the Casting

Engineering Centre, North University of China, and

Optimization of Injection Velocity for an AM60 Die - CastOptimization of Injection Velocity for an AM60 Die - CastOptimization of Injection Velocity for an AM60 Die - CastOptimization of Injection Velocity for an AM60 Die - CastOptimization of Injection Velocity for an AM60 Die - Cast

Dynamotor SupportDynamotor SupportDynamotor SupportDynamotor SupportDynamotor Support by ZHANG Yan, of Shenyang University

of Technology, also made a hit.

6. SummaryWe can see from this congress that although the research on

die casting technology and equipment in our country has made

a great progress and the die casting operation level has been

enhanced remarkably, the gap is still large compared with

developed comtries, especially in die casting equipment.

Therefore, the authors think that the future further research

and application on die casting technology in our country should

be conducted on several aspects as follows:

(1) Because of the tremendous contribution of advanced die

casting equipment to die casting operations, the investment in

the development of die casting machines, melting equipment,

and other auxiliary devices should be increased. Replacements

and technical innovations should be made to increase the

manufacturing level of die casting equipment in our country.

(2) Since computer simulation and emulation technology has

gradually matured, enterprises should pay greater attention to

and make full use of such advantages of the technology in the

development of products and process design. Shortening the

period of design and development for products, optimizing

processes, etc., all will increase the productivity, reduce the

costs of production, and enhance market competition.

(3) The automobile industry in our country is being rapidly

developed and the technology level of die casting aluminum

alloys for automobile parts has been increased. Therefore,

the development of complete of die casting technology,

especially for aluminum alloys with thin wall, complex shape,

and high-level properties, should be strengthened.

(4) In recent years, magnesium alloy and its die casting

technology have been developed quickly, and the technology

level has also been increased markedly, but the potential for

further development of magnesium alloy is still large, especially

for automobile parts. Therefore, its development should be

carried through in detailed depth to extend the scope of

application of magnesium alloy and to improve its properties.

(5) Fundamental research on squeeze casting and semi-solid

forming technology has made a great progress, but is still at

an early stage. Therefore, future research work should focus

on the development of related products and advanced

equipment to allow the advanced technology to be applied as

soon as possible.