Report Tkt

Analysis of casting defects at tkt high-tech cast pvt. ltd.

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ANALYSIS OF CASTING DEFECTS AT TKT

HIGHTECH CAST PVT. LTD.

By

THAKER YASH P.

SHAH ABHISHEK S.

VYAS MAHARSHI J.

PATEL RAKESH J.

Under the Guidance of

Mr. Kunal B. Thakkar

Director

TKT High-tech cast pvt. ltd.

A Report Submitted to

TKT High-tech cast pvt. ltd.

Nov-Dec 2015

M/S TKT high-tech cast pvt. ltd.

Plot No.6 Survey No. 254/1, Opp. Chharodi Railway station, Sanand-

Viramgam highway Taluka-Sanand Dist- Ahmedabad Pin-382170


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ABSTRACT

In the foundry and casting industries there are so many interception

they have to face. The main crux they are facing is casting defects. Due to

the casting defects the rejection rate of the manufacturing batch is raise

which drag the organization to the detriment. The losses perhaps harm the

firm abundant, like deterioration of the raw material, the wastage of time

and manpower too. The rejected products due to casting defects may

restrain the additional space in organization and also take some excerpt

manpower to handle the scrap due to the casting defects. It also leads to

delay the dispatching process. In conclusion the casting defects engender

contrariness for avocation of organization.

Therefore, here first of all we are finding the casting defects in our

current working industry TKT HIGHTECH CAST PVT. LTD. And we

enquiring the difficulties of casting defects and the type of casting defects

which are the industry facing presently.


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LIST OF DEFECTS

01. Ingate Shrinkage

02. Sand fusion

03. Mismatch

04. Cold shut or cold lap

05. Blow holes

06. Core tilting or core shift

07. Slag Defect

08. Scabbing


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1. Ingate Shrinkage

Fig :- Ingate Shrinkage

Possible causes

The density of a die casting alloy in the molten state is less than its density in the solid state. Therefore, when an alloy changes phase

from the molten state to the solid state, it always shrinks in size.

This shrinkage takes place when the casting is solidifying inside a die casting die. At the centre of thick sections of a casting, this

shrinkage can end up as many small voids known as shrinkage porosity.

If the shrinkage porosity is small in diameter and confined to the very centre of thick sections it will usually cause no problems.

However, if it is larger in size, or joined together, it can severely

weaken a casting. It is also a particular problem for castings which

need to be gas tight or watertight. Using too thin sprue can also cause the shrinkage defect.

Proposed Solution

Slight modification in design, using slightly thick sprue can minimize this defect.


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2. Sand fusion

Fig:-Sand fusion

Possible causes

Clay-bonded sand

Lustrous carbon content too low Proportion of low-melting-point substances too high

Moulding plant

Uneven mould compaction

Gating and pouring practice Uneven distribution of inflowing metal with resultant over-heating Temperature of liquid metal too high

2.3 Proposed solution Mould compaction should be even so that it doesnt

loose its porosity after loading. Make sure proportion of water content in mould making is

maintained


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3. Mismatch defect

Fig:-Mismatch

Possible causes

A mismatch is caused by the cope and drag parts of the mould not

remaining in their proper position.

This is caused by loose box pins, inaccurate pattern dowel pins or

carelessness in placing the cope on the drag.

Proposed solution

Make sure cope and drag part match properly in molding machine

Loose patent pins should be checked regularly


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4. Cold lap or cold shut

Fig:- cold lap or cold shut

Possible Causes Lack of fluidity in molten metal Faulty design Faulty gating High moisture content in mold sand

Proposed solution Maintain pouring time. Maintain pouring temperature. Make sure not to use damaged patent.


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5. Blowhole

Fig:-Blowhole

Possible causes Inadequate core venting Excessive release of gas from core Excessive moisture absorption by the cores Low gas permeability of the core sand Clay-bonded sand Moisture content of sand too high, or water released too quickly Gas permeability of the sand too low Sand temperature too high Bentonite content too high Too much gas released from lustrous carbon producer. Resin-bonded sand

Proposed solution Bentonite content should be maintained Use sand with high gas permeability Make sure moisture content in sand is not too high


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6. Core tilting or core shift

Fig:-Core tilting or Core shift

Possible causes Improper core sitting. Improper flow of molten metal while pouring. Using damaged cores.

Proposed solution Do not use damaged cores. Make sure core sit is proper in mould


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7. Slag Defect

Fig:-Slag Defect

Possible causes

Oxide content of the charge too high High impurity levels of oxides and hydroxides in charge materials Poor or slow dissolution of inoculants Ladle lining too highly reactive Poor deslagging of the molten metal

Proposed solution

Remove slag as much as possible at the time of melting. make sure inoculants is dissolved completely and also maintain

amount of inoculant added per mould.


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8. Scabbing

Fig:-Scabbing

Possible causes

Clay-bonded sand

Too little bentonite or poor bentonite quality in the moulding sand

Proportion of fine quartz in the sand too high Moulding sand too fine Insufficient conditioning of bentonite Too much salt in the sand

Gating and pouring practice

Sand heated up too severely by inflowing metal and long

exposure to radiated heat

Proposed solution

Maintain moisture content in moulding sand according to ambient

temperature.

Use proper amount of bentonite and also maintain quality of

bentonite.


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REFERECES

1. John Fernihough, Matthias Dr. Hoebel, Maxim Dr. Konter

Method Of Removing Casting Defects Application number-

EP20020405142

2. Ernst wiss Remedying Defects, Such As Blow Holes In Metal

Castings Application number-US884,346

3. Susumu Ihara, Hiroyuki Yoshimoto, Katsumi Mizuuchi, Hideo

Nishiumi, Takanobu Suzuki Method And Apparatus For

Detecting Internal Cavities In Casting Bars Application number-

US 05/864,910

4. Joseph M.VihtelicInvestment Casting With Improved As-Cast

Surface Finish Application number- US08/736,534

5. Hansen Method and equipment for feeding shrinkage voids in

metal castings Patent number- EP0738192B1

6. Pradeep kumar Mould modification for eliminating freckle defects

in roll casting Patent number- US3882942

7. Rajesh Rajkohle, J.G. Khan; Defects, Causes and Their Remedies

in Casting Process, A Review, International Journal Of Research

In Advent Technology, Vol-2,no-3, March- 2014, page no:03-09.

8. V.V.Mane, Amit Sata and M. Y. Khire New Approach to Casting

Defects Classification and Analysis Supported by Simulation

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