| |
|
Slide 1 :
|
OTHER FUSION WELDING PROCESSES THERMIT WELDING
ELECTRON BEAM WELDING
LASER BEAM WELDING |
|
|
|
|
Slide 3 :
|
Thermit welding has following applications Railway tracks repair of large steel castings and forgings large diameter shafts and frames for machinery and ship rudders The surface of the weld in these applications is often sufficiently smooth so that no subsequent finishing is required. |
|
|
Slide 4 :
|
ELECTRON BEAM WELDING Highly focussed ,high intensity stream of electrons impinging against the wok surface produce the heat. |
|
|
Slide 5 :
|
10-150kv Power density w/mm2 f1-heat transfer factor(0.8-0.95) E-accelerating voltage(V) I-beam current(amp) A-work surface area on which beam is focussed mm2(3X10-3 to 2000X10-3) |
|
|
Slide 6 :
|
Types of electron beam welding High vacuum welding
Medium vacuum welding
Low vacuum welding EBM-HV- Welding is carried out in the same vacuum as beam generation EBM-MV- Welding is carried out in the separate chamber where only a partial vacuum is achieved EBM-NV- Welding is carried at or near atmospheric pressure. |
|
|
Slide 7 :
|
Applications: work sizes ranges from foil to thick plate any refractory metal can be welded which is suited to AW automotive(steel torque converters, catalytic converters. Transmission components) , aerospace and nuclear industries Advantages: high quality welds with deep and narrow profiles, limited heat affected zone and less thermal distortion welding speeds are high compared to other welding processes no filler metal flux or shielding gas Disadvantages: high equipment cost, need for precise joint preparation and alignment limitation of performing in vacuum safety concerns: need shield from x-rays |
|
|
Slide 8 :
|
LASER BEAM WELDING Coalescence is achieved by:
Energy of highly concentrated and coherent light beam focussed on the joint |
|
|
Slide 9 :
|
Features: normally performed with shielding gases (helium,argon,nitrogen and carbon dioxide) to prevent oxidation filler metal is not added Advantages of LBW over EBW NO vacuum chamber NO X-rays laser beams can be focussed and directed by optical lenses and mirrors. Disavantages of LBW over EBW doesnot posses the capabilty for deep weldsand high depth to width ratios(5:1) maximum depth acieved is around 19mm whereas EBW used for 50mm Highly concentrated enegy in the small area of laser beam, the process is used to join small parts |
|