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What is shotpeen and magnaflux?

Discussion in 'Technical Q&A' started by zff, Nov 7, 2003.

  1. zff

    zff Karting

    Nov 1, 2003
    145
    Hawaii
    Full Name:
    Ken
    As far as I can tell, it's something you do to metal parts to make them better somehow. I was wondering what these terms mean, the process, the benefits, the downsides, typical costs, etc.

    TIA
     
  2. Dave

    Dave F1 Rookie

    Apr 15, 2001
    2,722
    Little Rock
    Full Name:
    David Jones
    I'm sure to be corrected but here goes....
    For example if you were rebuilding your engine, you could have your rods magnafluxed to see if there are any cracks in the metal,
    and then have them shotpeened to remove any surface defects or stress risers which could result in surface fatigue under load.
     
  3. CraigFL

    CraigFL Formula Junior

    Jan 17, 2001
    954
    Panama City, FL
    Full Name:
    Craig
    Magnaflux is a trademark process to find surface and subsurface flaws in magnetic material. This is done by spreading a thin layer of iron filing material iron the surface of the piece being tested and applying a very strong local magnetic field. Cracks in the material stand out with the alignment of the iron particles because at every crack, a North and South pole exists causing the iron filings to defeine the crack. An experienced person can also see subsurface imperfections in the iron filings too.

    Peening is a process to apply a surface compressive stress in the part. Since most material applications fail by tension(in a fatigue type situation) -- where a small imperfection or stress riser exists. The intent is to provide a high enough initial compressive stress that when the working load stress is added, the net stress never goes positive -- or at least stays less positive. (The higher the positive stress, the sooner the part will fatigue and fail.) Shot Peening uses metal shot but depending on the material, glass beads or even walnut shells.
     

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