BEAM WELDING.ppt

A SEMINAR REPORT ONBEAM WELDING

Fig:1.1 electron beam welding

The electron beam is produced in a high vacuum environment by an electron gun ,usually consisting of a tungsten or tantalum cathode, a grid or forming electrode and a anode.A stream of electrons is given off from a tungsten filament heated to about 2200 c.The electrons are gathered, accelerated to high velocity and shaped into a beam by a potential difference between cathode and anode.

The beam is collimated and focused by passing through the field of an electromagnetic focusing coil or” magnetic lens”.Beams typically are focused to about 0.25 to 1 mm diameter and have a power density of about 10kw/mm2, which is sufficient to melt and vaporize any metal.The operation is carried out in a vacuum, which enables, the beam source to be at a distance of up to about 1 m from the work. Deep penetration with a very narrow heat affected zone is achieved by this process.Aluminum can be fused up to a depth of about 40 mm and stainless steel up to about 30 mm,with a width of fusion area about one tenth of a penetration.

1. An electron beam gun.2. A vacuum chamber.3. Moving the work under the beam

while welding.4. Microscope for viewing the work.

1. Weld produced are made of a high quality and can made at high speeds.

2. The fusion zone and heat affected zone are narrow.

3. Distortion is eliminated due to narrow beam.4. Welding joints are clean and bright having no

oxide, scale or flux slugs thus no need to clean.5. Electron beam welds have a highly desirable

depth to width ratio.6. Small thin parts can be welded to heavy sections.7. Precise control is possible.8. Filler metal is not required

ANY QUESTION