ELECTRON BEAM WELDING

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ELECTRON BEAM WELDING

• The electron beam gun has a tungsten filament
  which is heated, freeing electrons.
• The electrons are accelerated from the source
  with high voltage potential between a cathode and
  anode.
• The stream of electrons then pass through a hole
  in the anode. The beam is directed by magnetic
  forces of focusing and deflecting coils. This
  beam is directed out of the gun column and
  strikes the workpiece.
• The potential energy of the electrons is
  transferred to heat upon impact of the workpiece
  and cuts a perfect hole at the weld joint. Molten
  metal fills in behind the beam, creating a deep
  finished weld.

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How an Electron Beam Machine Works

• The EB system is composed of an electron beam
  gun, a power supply, control system, motion
  equipment and vacuum welding chamber. Fusion of
  base metals eliminates the need for filler
  metals. The vacuum requirement for operation of
  the electron beam equipment eliminates the need
  for shielding gases and fluxes.

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• The electron beam stream and workpiece are
  manipulated by means of precise, computer driven
  controls, within a vacuum welding chamber,
  therefore eliminating oxidation, contamination.

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ELECTRON BEAM WELDING
                                                     
                                                                                                                                                         
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ELECTRON BEAM WELDING
                                                     
                                                                                                                                                         
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Electron Beam Welding

• Electron Beam Welding joins ferrous metals, light
  metals, precious metals, and alloys, to
  themselves or each other. Multi-axis EB
  control High ratio of depth-to-width Maximum
  penetration with minimal distortion Exceptional
  weld strength Ability to weld components up to
  10 feet in diameter High precision and
  repeatability with virtually 0 scrap
  Versatility from .002" depth to 3.00" depth of
  penetration

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Electron Beam Welding Facts

• Electron Beam Welding Advantages Maximum amount
  of weld penetration with the least amount of heat
  input reduces distortion Electron beam welding
  often reduces the need for secondary operations
  Repeatability is achieved through electrical
  control systems A cleaner, stronger and
  homogeneous weld is produced in a vacuum The
  electron beam machine's vacuum environment
  eliminates atmospheric contaminates in the weld
  Exotic alloys and dissimilar materials can be
  welded Extreme precision due to CNC programming
  and magnification of operator viewing Electron
  beam welding frequently yields a 0 scrap rate
  The electron beam process can be used for salvage
  and repair of new and used components

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Electron Beam Welding Speeds/Depth of Penetration
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• Electron Beam Welding Limitations The necessity
  of an electron beam welding vacuum chamber limits
  the size of the workpiece EBTEC's maximum
  chamber size is 11' 4" wide x 9' 2" high x 12'
  deep

Electron Beam Welding Speeds/Depth of Penetration
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• Electron Beam Welding (EBW) is a unique way of
  delivering large amounts of concentrated thermal
  energy to materials being welded. It became
  viable, as a production process, in the late
  1950's. At that time, it was used mainly in the
  aerospace and nuclear industries. Since then, it
  has become the welding technique with the widest
  range of applications. This has resulted from the
  ability to use the very high energy density of
  the beam to weld parts ranging in sizes from very
  delicate small components using just a few watts
  of power, to welding steel at a thickness of 10
  to 12 inches with 100 Kilowatts or more. However,
  even today most of the applications are less than
  1/2" in thickness, and cover a wide variety of
  metals and even dissimilar metal joints

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• Two welding modes are used in the
  (EBW)1-Conductance modeMainly applicable to
  thin materials, heating of the weld joint to
  melting temperature is quickly generated at or
  below the materials surface followed by thermal
  conductance throughout the joint for complete or
  partial penetration. The resulting weld is very
  narrow for two reasonsa- It is produced by a
  focused beam spot with energy densities
  concentrated into a .010 to.030 area.b- The high
  energy density allows for quick travel speeds
  allowing the weld to occur so fast that the
  adjacent base metal does not absorb the excess
  heat therefore giving the E.B. process it's
  distinct minimal heat affected zone.2-Keyhole
  modeIt is employed when deep penetration is a
  requirement. This is possible since the
  concentrated energy and velocity of the electrons
  of the focused beam are capable of subsurface
  penetration. The subsurface penetration causes
  the rapid vaporization of the material thus
  causing a hole to be drilled through the
  material. In the hole cavity the rapid
  vaporization and sputtering causes a pressure to
  develop thereby suspending the liquidus material
  against the cavity walls. As the hole is advanced
  along the weld joint by motion of the workpiece
  the molten layer flows around the beam energy to
  fill the hole and coalesce to produce a fusion
  weld. The hole and trailing solidifying metal
  resemble the shape of an old fashion
  keyhole.Both the conductance and keyhole welding
  modes share physical features such as narrow
  welds and minimal heat affected zone .The basic
  difference is that a keyhole weld is a full
  penetration weld and a conductance weld usually
  carries a molten puddle and penetrates by virtue
  of conduction of thermal energy.

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