ENVIRONMENTAL IMPACT ON ALUMINIUM DIE CASTING AND … · 2020. 8. 18. · There are two types of defect in Aluminium die casting 1. Surface defect 2. Internal defect SURFACE DEFECT

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ENVIRONMENTAL IMPACT ON ALUMINIUM DIE CASTING AND

DEFECT ANALYSIS

Devinder*1, Akhilesh Tewari*2

*1M.Tech Student, Department Of Mechanical Engineering, Faridabad College Of Engineering And

Management, Faridabad Haryana India.

*2Assistant Professor, Department Of Mechanical Engineering, Faridabad College Of Engineering And

Management, Faridabad Haryana India.

ABSTRACT

Aluminium die casting is a process used to transform molten metal into automotive gearbox housing,

wheel, and electronics components, among many other uses. It is used because it is a very efficient

method of achieving near-net shape with the required mechanical properties. Life Cycle Assessment is a

technique used to determine the environmental impact of a product or process. The Life Cycle Inventory

(LCI) is the initial phase of LCA and describes which emission will occur and which raw materials are

used during the life of a product or process. Defect Analysis is a technique in which we study a different

type of defect in casting and how to rectify them in the inventory of the product or process. This study

focuses on one process, which is die casting. Still, different techniques are to be used to solve the problem

during the casting process or inventory defect analysis.

KEYWORD: Aluminium die casting,life cycle assessment, life cycle inventory, environmental impact,and

defect analysis.

I. INTRODUCTION

Metal casting plays a vital role in all sectors of our economy. Casting is the oldest method of

manufacturing. There are several industries where castings are used like locomotive, car, truck aircraft,

and factories everywhere. In metal casting, metal is melted form and poured into a cavity, and after

solidification of the metal in the cavity, the metal takes the exact shape of the cavity. The solidified object

is called casting or mold.

The casting also called mold—the shape and size of the product match with requirement. Die casting

process which uses Permanente mold, date back to mid AD-1800

Aluminium die casting is a manufacturing process used to form the complex shape from Aluminium. Fifty-

four million tonnes of die casting cast per year, the world’s most significant production of Aluminium die-

casting to produce in the world Australia. Alone, Australia produces 4 million tonnes of die-cast per year

worldwide.

Life cycle assessment (LCA) is a technique that is common in assessing the environmental impact of a

product or process. Detailing to all the input of process or product and all the output and assigned the

value them, a total value can be calculated to the environmental impact on product or process

Types of Defects

Defect analysis method (DAM) is a technique which is related to defect generated during the process or

inventory of product. There are several defects which are generated during the process like

(1) Surface Defect

(2) Internal Defect

Advantages of die casting

Molten material flow into tiny section so that intricate shape can be made of this process; as a result of

many processes, forging, machining, welding, etc. are to be minimized

Practically to possible cast any material like ferrous or nonferrous

The necessary tool required to casting very simple and inexpensive

Size and shape of product variation are possible



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Casting is lightweight

By the die casting batch production is possible

Limitations

Die casting is a labour-intensive process

The initial cost is very high

For running software high skilled employers to be required

Environmental pollution to be created

It is not possible to achieve all metal products

The defect is generated like an air cavity, chip off pinhole, etc.

II. LITERATURE

ALUMINIUM DIE CASTING

Aluminium die casting is a process used to complex shape in which molten metal is poured into

the cavity to form a mold. Product is formed to Aluminium die-casting light in weight and inexpensive,

respectively. Aluminium die casting is a very energetically requirement process for melting and remelting

of Aluminium. Aluminium die casting is three type

(1).High pressure die casting

(2).Cold pressure die casting

HIGH-PRESSURE DIE CASTING (COLD CHAMBER DIE CASTING)

High-pressure die casting involves the injection of molten metal into a steel die under high pressure.

Molten metal is poured into a shot sleeve by either ladle or a dosing furnace. A piston moves within the

shot sleeve and moves the molten metal up the gate of the die at a slow speed, the metal reaches at the

gate of dying molten metal move at the gate speed of 72m/s high pressure up to 10 Mpa is required. Due

to the high pressure and velocity of the metal, the flow of metal is automated and fills the cavity in spray

type form; when the cavity is full, the piston is applied again high pressure to remove porosity or air

bubbles. The Aluminium will then be solidified in the cavity.

Die generally split into two halves form one port is fixed to tie bar, and the other is movable.

The movable part of the die contains an injection pin to remove the casting. A systematic diagram of high

pressure die casting is shown in the figure.

Figure-1: High pressure die casting



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The high-pressure die casting also used to cast like metal like zinc, brass, and magnesium. Cold chamber

dies casting machine work on the principle of high pressure. A cold chamber machine is shown in the

figure. In which molten metal is feed by shot sleeve and plunger forced the metal hydraulic pressure to fill

die.

LOW-PRESSURE DIE CASTING (HOT CHAMBER CASTING)

This manufacturing process uses a steel die, which is located above a holding furnace of molten

Aluminium. The die is coated with a ceramic-based die coat which is applied before and up to 200 shot

depending upon condition The metal in the holding furnace is pressure to 1bar. The metal is forced up a

riser tube and into die. The metal flows into die in the solid form and fill the die from bottom to top

because turbulence is minimized with high integral casting with minimum porosity low pressure-based

hot chamber machine is shown in figures in this injection mechanism immerse into baths of its metal

holding furnace. The furnace is connected to the machine by metal need systems called a gooseneck. The

injection plunger rises a port in the injection cylinder opens, allowing molten metal to fill the cavity as the

plunger moves downwards it seal the port. This type of casting used for low melting point metal like zinc

and copper.

Figure-2:. Hot chamber casting

Die casting process cycle

Process cycle consists of four steps, clamping, cooling, injection, election, four steps shown in the figure.

The die closed and the molten metal is ladled into cold chamber shot sleeve.

The plunger pushes molten metal into die cavity where it is held under pressure until solidifying of

object

And next step to open the plunger advanced to ensure that the casting remains in the core half of the

die

The ejector pin pushes the casting out of the core half of the die, and the plunger returns to its

original position.



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Figure-3: Die casting process cycle

LIFE CYCLE ASSESSMENT

Life cycle assessment is a technique that deals with the environmental impact on the inventory of the die

casting process. The main object of this study was to use the life cycle inventory technique to ass3 an

Aluminium product manufacture using the casting process and to evaluate the validity of the technique

concerning this process. This work detail the emission of air, water, and landform process also some of

the more harm3 impacts associated with such as greenhouse gas, human toxicity, etc.

ENVIRONMENTAL ISSUES

Concerning the emission from the furnace, the foreign matter from the furnace exhaust flue is a mix of

sulphur dioxide, carbon monoxide, carbon dioxide with oil fog, and dust from contaminated scrap

material.

The dust content increases at the time of dross removal and level of emission are dependent upon the

construction and method of furnace operation.

One of the emissions from the burning of natural gas is nitrogen oxide. The temperature effect the

emission increases with increasing temperature.

There is no emission to be created during the casting of mold. Some solid waste emitted during casting is

shown in the table.

Position of the plunger. This solid waste has created the problem of the movement of the plunger, and

delay time in the shot of plunger also decreases the production rate. Another solid waste that creates

pollution in the inventory area is a chip off material due to the looseness of the die. This waste is harmful

to the environment and operator of the machine.

Chemical waste, which is a liquid type of waste, also creates water pollution in the plant.



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DEFECT ANALYSIS

Surface defect analysis is a technique which is a concern with the defect created during the cast3 process

and inventory of product.

There are two types of defect in Aluminium die casting

1. Surface defect

2. Internal defect

SURFACE DEFECT

COLD SHOT

Cold shot defects in Aluminium die casting is seen; generally, this defect is created due to less die

temperature. Another reason for cold shot die coat is less or more time.



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Figure-4: Cold shot

CHIP OFF

A chip off defect is due to some material is stick to die, and when casting is extracted, then this material

comes with the product.

SHRINKAGE DEFECT

Shrinkage defect is coming as the temperature of molten metal is low, and another reason for the

temperature of die is low.

CRACKING DEFECT

The cracking defect is generated in die due to the quantity of iron is more in the material ratio of molten

metal.

BLISTER DEFECT

Blister defect comes in casting due to the pressure less due to molten metal don’t fill die properly, and

air cavity or porosity remains in casting

SOLDERING DEFECT

Soldering is types of defect which is generally in die due to more tightness of die and friction between die

is more than the requirement of casting

CACHING DEFECT

Caching defect is another type of defect created due to less die coat on die and miss-match of dying, then

caching defect is created.

FLASHING DEFECT

Flashing defect is created due to looseness of the die, and when die close during the process, solid molten

metal is flash off above and side of the machine, which is harmful to the operator of the machine

INTERNAL DEFECT

The internal defect is also called machining defects because of these defects seen during the machining of

casting. There are some internal defect is discussed below

BLOW HOLE

Blowhole in casting is due to air or porosity in the product and can be visible during machining.

PINHOLE

Pinhole in die casting is shown due to the air cavity inside the casting. Some time pin of ejector doesn’t

come to properly requirement then, at this timing defect can be shown.

THERMAL DEFECT

This defect generally crated after the complication of the due to the high-temperature microstructure of

casting change and small expansion take place.

RUNOUT DEFECT



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The defect is generally carried out when molten metal is leaking ours from the cavity.

SLAG INCLUSION DEFECT

This type of defect is called a scab defect. This defect can be seen by the naked eye, in this defect, few

millimeter-thick layers of irregular impurities on the upper surface of the casting, and this defect is

similar to rat-tail defect

III. METHODOLOGY

LCA METHODOLOGY

The goal of this study is to determine the environmental impact on Aluminium die casting as a process.

To do this is a single casting process of the product was evaluated as well as, the process only was

considered from gate to gate.

Material into the plant either as solid, liquid waste, emission, recycled materials, and decrease cast

product. Significant tonnage of raw was also required to consider as part of this study.

For example, natural gas, electricity, Aluminium, water, and die lubricant, the manufacturer of the

thousands of consumable used in the plant, was not considered for this study.

Building and grounding waste have not considered due to lack of reliable data of ADADC12

The system boundary includes off-site emission from the energy source for CNG, LPG ELECTRICITY, et

.waste, also been include for the industrial waste, but sewage flow not considered. The table shown below

explains the waste of plant

PROCESS PLAN

To remove waste and pollution, contaminated particles can be evaluated by making a complete plan.

In this study, we aim to answer the following question.

1. Which technical pollution reduction option is reliable for reducing the environmental impact of an

Aluminium process die-casting plant.

2. What are their technical potential and associated cost for the plant?

POLLUTION REDUCTION OPTION

Criteria for choosing pollution reduction options:

The pollution reduction option includes the following criteria.

1. The option aims to reduce the pollutant released during the operation taking place within the plant

gate.

2. The option is to reduce the liquid and solid waste.

3. The option is presently available at industrial technologies.

4. The reduction option aim at releasing the pollutant emitted by the current industrial process.

5. The option doesn’t reduce the production rate of the company, and it also does not affect the safety

performance of the company.

Types of pollution reduction option:

In this section, we discuss the pollution reduction option and its characteristics. In total, we discuss 11

reduction options, .which reduces the pollutant of the casting process. The table shown the pollutant

emitted and how to reduce them.



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Melting pollutant reduction

To reduce pollutant emissions during melting following to be used:

1. Filter and scrubber

2. Alternate deoxidation

3. Alternate degassing

4. Alternate metal loading in the furnace



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Filter and scrubber

The fabric filter is the best method to reduce heavy pollutant like copper, fluoride, hydrogen, etc. some

other metal particle-like cadmium, Nickle, Lead, ceramic, etc

Wet scrubber reduces hydrogen, fluoride, and copper emission.

ALTERNATE DEOXIDATION

For the melting of metal, we use the deoxidation agent like natural gas in place of electricity, which is

created the heating effect by using this method, two %reduction of pollutants takes place. For this

purpose, we use a granular agent who has size two %and reduce the hydrogen and fluoride up to

minimized level.

DEGASSING TECHNIQUE

The next approach to reduction is degassing. It is a new technique in which impeller station bu nitrogen

gas using help in the reduction of pollutants to the melting bath. By using this technique, hydrogen, and

fluoride, Aluminium garbage can be reduced. This technique also used to reduce porosity in molten baths.

Using impeller stations solid agent does not require fluoride-containing compound.

TRIMMING

By using this reduction technique, the scrap rate of casting can be reduced .some heavy metal like nickel,

lead, cadmium, etc. Reduce some other compounds like oil, grease, Aluminium dross.

DEFECT REDUCTION IN ALUMINIUM DIE CASTING

After the discussion about the defect of the casting lte, we understand how we increase in the life cycle of

casting by reducing defect.

ADDITION OF Ni and Sr In Aluminium

The first stage of this study to developing appropriate casting method which involves advantage to inc

mechanical properties of Aluminium alloy 380 if we added Ni and Sr the ultimate tensile strength and

elongation to failure increases 215 Mpa and 5.4% respectively which is in conventional die casting

method 173.5% and 1.0% respectively

Also, this thermal property of Aluminium increases.

SILICON ADDITION IN ALUMINIUM

The effect of the Si content Aluminium in die casting in the ratio of Al-3.5% and Si-5.5% wt per cast,

which in conventional is 1.5 and 3.0 cast up to 700 Celsius in the spiral and hot tearing method following

properties of aaluminium390 inc.

1. Fluidity increases

2. Solidification shrinkage dec

3. Pressure tightness increases

4. Hot shortness reduce

5. Stiffness increases

6. Specifics gravity dec

7. Thermal expansion dec

8. Corrosion-resistant decrease

COPPER ADDITION IN ALUMINIUM

By the addition of copper in Aluminium in 2 to 3% hardness of Aluminium increases. Cupper is 3times

denser than Aluminium to increase the fluidity in copper content Ti 2% mix with alloy corrosion

resistance is inversely proportional to the copper

LASER COATING IN DIE

By the laser coating in die defects created during the casting is decreased like a blowhole, air cavity,

caching pinhole, etc.



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Zinc ADDITION in ALUMINIUM

The addition of zinc .5% to .3% due to high solubility of zinc in Aluminium Mechanical properties inc

and a cracking defect is decreased.

EXPERIMENTAL RESULT

The casting faces several defects; these defects generally created due to variations in temp, speed, metal

composition, and environmental issues. The max temp of the die H13 of aluminium alloy A380 is 150-

200C. In the high pressure die casting., casting has a lot of defects, the defect can be removed if the die

temperatures, materials composition, speed variation, filling temperature of molten metal is to controlled

for normally for alloy A380 the variation of the parameter is

Metal used-A380

Ram velocity-2-4m/s

Die temp. -150-200

Melting temp-670-680

Speed melt in gate-55m/s

The melting temp of the die measure at the beginning of the filling of molten metal. The removal of the

defect an experiment is to do on the die casting machine IDRA1600. The cold shot in die occur at 150C

temp This defect is coming out when the metal flow from shot sleeve to gate at low speed due to when die

temp is low and other defects like porosity due to air entrapped also created due low speed of the

plunger in which air fill due to delay in filling of molten metal for removing of the defect following data

can be taken

Ram velocity-3m/s

Die temp-200C

Metal temp-690C

Speed of melt in a gate -60m/s

Material composition-

Si-3. 9%

Ti-2%

Cu-. 3%

Zn-1. 1%

Remaining other metal

The temp variation of die and metal is shown in figure below.

The temp variation of the die and melting metal is shown in fig. The difference in temp shows that defect

probably occurs when the die temp is less than 200C.max temp is dependent upon the cooling time of

casting.

Conclusion- die temp of H13 is 200C for less porosity and other defects in casting.



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Figure-5

IV. CONCLUSION

The discussion chapter follows the point of the study that have evacuated from the previous chapter. The

LCA tool is discussed in the methodology and applicability to determine to die casting. The value of the

study presented with outputs and suggested improvement to the process further work is presented

followed by a conclusion study.

The LCA METHODOLOGY is well suited to this process and gives useful information about the process, but

the result of the study should not be considered. The methodology has many different aspects that can be

changed from any LCA needs to be looked at carefully to determine items such as data quality and the

system boundary.

The reduction of pollution aims to achieve by following the steps discussed above. It helps in the

reduction of excessive use of raw materials and the reduction of environmental pollution created during

the processing plant. Defect analysis is essential to control the pollution and the use of casting durable for

a long time. And help to the reduction of cost per unit of a piece of casting and tell us to manage the better

quality of the product with better precision.

Life cycle assessment is an acceptable tool for the analysis of aluminium high-pressure die casting

process. During study this process, it is necessary to remember the reliability and accuracy of data.

a. It can be concluded that a careful selection of environmental system analysis tool is essential. In this

thesis, the selection of tools was based on the desired characteristics of a set of alternative strategies

on pollution reduction.

b. Selection of reduction option which is readily available at commercial and technology level

c. The cost of the method of reduction is minimum.

d. The method of reducing pollution control is not affected by the product in the rate of company and

performance.

V. REFERENCES [1] Michael Johan Robert (2003), Life cycle Inventory of aluminium die casting., School of

Engineering and Technology, Deakin University.

[2] Patricia Gomez, Dancil Elduque, Judith Sarasa, Carmel Rima, and Carlos Javierre, (2016) “

Influence of composition on the Environmental Impact of a Cast aluminium alloy, University of

Narogaza

[3] Hans Ivar Laukli, (2004), High pressure die casting of aluminium and magnesium alloy grain

structure and segregation characteristics, Norwegian university.

[4] Model selection of manufacturing, IIT BOMBAY 2012

[5] Belmiro Ne to, 2007 “MIKADO a discussion support



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[6] Tool for pollution Reduction in Aluminium pressure

[7] D casting”, Wageningen University, Dutch

[8] Anton Bjuren STEDT, 2015, “Imperfection in Recycled aluminium-silicon cast alloy,” School of

Engineering, Jonkoping University

[9] Mr. RohanDAhirrao, B. G Marlapalle, feb2019, “A Review paper on Analysis and optimization of

aluminium casting parameters,” IRJET

[10] Madhav Rao Gonvindaraju1998” development of an innovative laser-based coating process for

extending lifetime of metal. SciTech.

Documents

ENVIRONMENTAL IMPACT ON ALUMINIUM DIE CASTING AND … · 2020. 8. 18. · There are two types of defect in Aluminium die casting 1. Surface defect 2. Internal defect SURFACE DEFECT