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

    0

    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

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

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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.

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

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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

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

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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.

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

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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

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

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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

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

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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.

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

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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

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

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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

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

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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.

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

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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.

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

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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