Indian Bofors gun's barrel bursts during trials

Discussion in 'Indian Army' started by Ray, Oct 16, 2013.

  1. Ray

    Ray The Chairman Defence Professionals Moderator

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    Indian Bofors gun's barrel bursts during trials

    A barrel of the indigenous - version of the Bofors howitzers burst during their trials in the Pokharan range, delaying plans to induct these artillery guns into the Army.

    The Defence Acquisition Council had recently approved the procurement of 144 such guns by the Army which are being manufactured by the Ordnance Factory Board, Jabalpur.

    During the recent trials of the gun in Pokharan, the barrel of the gun burst when the Army was conducting the user trials for approving the gun for induction in the Army, sources said here.

    The OFB has now been asked to carry out a defect identification inquiry (DII) by the Defence Ministry to ascertain the reasons behind the bursting of the barrel during the crucial trials, they said.

    The user trials are carried out by the Services for approving the product being tested for induction.

    The gun has been performing very well so far but the mishap will delay the user trials for another three to four months, they said.
    Defence Minister AK Antony has been taking personal interest in the development of this programme and has asked both the Department of Defence Production and the Army to cooperate fully for making it successful.

    The gun design, provided as part of technology transfer, has been gathering dust due to the taint associated with Bofors in the light of the payoffs scam.

    If successful, the project would save the country millions of rupees and give the Indian Army much needed firepower.

    The Army has failed to procure even a single piece of artillery after the Bofors scandal erupted in 1980s. All attempts to procure howitzers have had to be cancelled due to one reason or another.

    Indian Bofors gun's barrel bursts during trials - The New Indian Express

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    Unfortunate..

    However, all is not lost!

    The barrel is the critical part where the steel has to be 100% pure and without impurities and the autofrettage process perfect.

    [​IMG]

    [​IMG]

    [​IMG]

    Autofrettage is a process that creates an internal stress in a component, similar to the shot blasting. Autofrettage is used in most cases for the inner pressure active components without (tubes) and with cross borings (rails).

    When a component is pressurized by an autofrettage pressure, which is much higher than the working pressure and is dependent on the material used, hardness, and the geometry of the component, the inner boring will be formed plastically and the deeper areas of the component wall will be formed elastically.

    After relieving the autofrettage pressure from the component, the elastically formed areas try to return to their original state while the plastically formed areas prevent this process. Therefore internal stresses are created in a huge part of the wall thickness which tries to work against the stresses that arise from normal working pressure.

    Under working pressure the stresses inside the component do not move between 0 and a maximal value any more, but start in the pressure area below 0 and end at a much lower maximal value.

    [​IMG]

    As you can see from Figure 1, the resulting working loads (e. g. in the pipe) can be reduced considerably.

    A working pressure which would have led to a failure of the component prior to autofrettage can now be used endlessly – at least for a considerably longer time – without failure. This can lead the design engineer to look for cost saving strategies (i.e. material selection, material reduction etc.).

    If you want to use the same positive effects of autofrettage for bent pipes, the autofrettage has to be done after the bending. If autofrettaged after bending, the internal stresses of autofrettage will overlie or neutralize the internal stresses and the effects of autofrettage will be lost.

    [​IMG]

    If you have components with cross cutting there will be an additional effect: On those areas around the drill hole there is a stress concentration. Therefore these are the weak sections inside a component. Cracks in this part are very often the reason for failure.

    If you have high dynamic working pressures even the autofrettage cannot prevent a crack in these cross cuttings.

    [​IMG]

    The crack will just grow up to a certain length and will then be stopped by the pressure internal stresses that are inside the wall, picture 3. The internal stresses “press” the crack together.

    To receive the requested internal stresses by an autofrettage, the pressure of the autofrettage just has to be held a short time. A longer time does not increase the internal stresses inside the component, but leads to a strong widening of the inner boring.

    As the pressures of autofrettage are calculated in that way that a huge part of the wall thickness is plastic, the pressure does not have to be reached with absolute exactness.

    Which deviations are acceptable and which not, depends on every single case.

    The autofrettage of a component in more than just one case should be avoided.

    http://www.maximator-test.com/about/wp-autofrettage.php
     
    Last edited: Oct 16, 2013
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  3. debasree

    debasree Regular Member

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    Early hiccus but i m hopefull indiganisation is the best way forward
     
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  4. Decklander

    Decklander New Member

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    I heard that the failure was due to the 155mm round. The round exploded within the barrel which does happen at times.
     
  5. LETHALFORCE

    LETHALFORCE Moderator Moderator

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    Is this news worthy?
     
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  6. jmj_overlord

    jmj_overlord Regular Member

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    any news on the deal with US to acquire howitzers ? maybe till achieving indigenisation imports is the best way..........
     
  7. Ray

    Ray The Chairman Defence Professionals Moderator

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    It is not really newsworthy, but one that can generate debate.

    It is so rudimentary that all can participate and will calm those who say that this is a defence forum but very little is discussed of defence.

    It is an opening for such people to chip in.

    It could not have been easier than this to do so! ;)
     
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  8. Blackwater

    Blackwater Veteran Member Veteran Member

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    Indian Bofors gun's barrel bursts during trials


    :taunt::taunt::taunt::taunt::taunt::taunt::taunt:
     
  9. Bheeshma

    Bheeshma Regular Member

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    OFB quality control is legendary. Why not pass on the manufacturing to TATA , Godrej etc
     
  10. sayareakd

    sayareakd Moderator Moderator

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    Relax guys when you make it first time you are boud to have these small set backs, learn from it fast, correct the problem and make sure everything went smooth next time.
     
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  11. maomao

    maomao Veteran Hunter of Maleecha Senior Member

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    Sometimes I get a feeling of sabotage or may be it's a natural bias of a nationalist! ;)
     
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  12. LETHALFORCE

    LETHALFORCE Moderator Moderator

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    You misunderstood ray I meant is this something that a newspaper saw fit to publish
    Every military in the world deals with faulty equipment/weaponry, I feel there is an agenda
    Against indigenous weaponry especially with so many countries bidding for big ticket
    Artillery deals.
     
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  13. Dark Sorrow

    Dark Sorrow Respected Member Senior Member

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    Because they don't possess adavanced metallurgy.
    Why should tay payers pay for tata or godrej's modernization.
     
  14. Ray

    Ray The Chairman Defence Professionals Moderator

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    I did understand what you meant.

    It is just that there is so much of grouse that you find in the Suggestion thread that this is a Defence Forum and we discuss everything else.

    I have tried to initiate many defence thread on weighty military issues, but they have always fizzled out and even come to the state of which camouflage uniform design is 'sexy'.

    So, I tried this one which I thought will elicit comments given that there is a lot of posts on a verity of artillery pieces to include some gun by Tata or was it L&T?

    So, if Tata is producing, I thought we could have a look as to our own OFB who have the blueprints and yet........;)

    IOf you ask me personally, this barrel bursting is not something new.

    It happens.

    the 105 IFG an OFB produce also had barrel burst after production.

    It was found to be because of faulty autofrettage. because the electricity was erratic during manufacture that seriously affect this very important process. Instead of rejecting the piece, they continued with the process once the electricity returned and that produced weak spots. OFB ws more keen to please the bureaucrats with record figures, which is the sad commentary of the command economy.
     
    Last edited: Oct 17, 2013
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  15. The Messiah

    The Messiah Bow Before Me! Elite Member

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    milawat toh khubiat hai is desh ki :yey:
     
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  16. Ray

    Ray The Chairman Defence Professionals Moderator

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    [​IMG]

    Life is cheap!
     
  17. Neuve_Chapelle

    Neuve_Chapelle Regular Member

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    The fact that GCF Jabalpur began manufacturing IFGs in 1973, and had barrel bursts to begin with, one would imagine that they have at least implemented a basic manufacturing and QA process in 40 years. Throw in the 130/155 and FH77 upgrades too, and there was plenty of opportunity to learn. And I am sure accusations will begin flying fast and thick soon as I say that, but I ask, can a monopoly still claim not to have requisite knowledge etc even after 40 years of learning?

    Code:
    History of Gun Carriage Factory:
    
    1905 : GCF received 1st order for 500 Transport Carts
    1909 : First carriage produced
    1947 : Manufacture of Civil Stores e.g. Steam Road Rollers, Railway Stores, Oil Expellers 
    1959 : Prodion of Shaktiman, Nissan -1 Ton & Jonga 
    1963 : Manufacture of 40 mm AA Gun L/70, 81mm & 120mm Mortars & 106mm RCL 
    1965 : Manufacture of Vijayanta Tank Sub-Assys
    1968 : Manufacture of 1st indigenously designed Gun 75/24 Pack Howitzer 
    1973 : Manufacture of 105 mm Indian Field Gun. 
    1984 : Manufacture of 105 mm LFG with Superior Material 
    1987 : Manufacture of T-72 Gun Article
    1988 : Manufacture of 51 mm Mortar
    1995 : Development of 12 Bore Pump Action Gun
    1996 : IS/ISO-9001:2008 Certification
    1998 : NABL Accreditation of Testing Labs
    2001 : 130/155 SOLTAM Upgradation 
    2005 : Prahari Gun System developed for Navy & Coast Guard 
    2006 : KAVACH Chaff Launcher developed.
    2007 : Successful proof firing of Upgraded 155 FH B02 Gun
    2008 : Manufacture of Tank T-90 Gun Article.
    2009 : L-70 Upgradation in collaboration with M/s BEL
    2010 : Modified Loading Trough and Apparatus Air Lifting for 105 mm LFG developed
     
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  18. Armand2REP

    Armand2REP CHINI EXPERT Veteran Member

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    That has been said for every indigenous project to date, where are they now?
     
  19. W.G.Ewald

    W.G.Ewald Defence Professionals/ DFI member of 2 Defence Professionals

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  20. sayareakd

    sayareakd Moderator Moderator

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    True but perfect gun wont jump into our lap like that. It take tume and IA has learn it hard way. Thy need to work out how to achive objective in min time frame.
     
  21. Sridhar

    Sridhar House keeper Moderator

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    It was a success back in dec

    Desi Bofors gun passes the test - Times Of India

    What happened now , is it because of the angle of fire , where it needs to withstand more pressure but failed ?
    or because of the new propellents they are trying

     

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