07-10-2010, 11:20 AM
WELDING.ppt (Size: 309.5 KB / Downloads: 319)
WELDING
-Welding is a materials joining process which produces coalescence of materials by heating them to suitable temperatures with or without the application of pressure or by the application of pressure alone, and with or without the use of filler material.
-Welding is used for making permanent joints.
-It is used in the manufacture of automobile bodies, aircraft frames, railway wagons, machine frames, structural works, tanks, furniture, boilers, general repair work and ship building.
TYPES
-Plastic Welding or Pressure Welding
The piece of metal to be joined are heated to a plastic state and forced together by external pressure
(Ex) Resistance welding
-Fusion Welding or Non-Pressure Welding
The material at the joint is heated to a molten state and allowed to solidify
(Ex) Gas welding, Arc welding
Classification of welding processes:
(i). Arc welding
Carbon arc
Metal arc
Metal inert gas
Tungsten inert gas
Plasma arc
Submerged arc
Electro-slag
(ii). Gas Welding
Oxy-acetylene
Air-acetylene
Oxy-hydrogen
(iii). Resistance Welding
Butt
Spot
Seam
Projection
Percussion
(iv)Thermit Welding
(v)Solid State Welding
Friction
Ultrasonic
Diffusion
Explosive
(vi)Newer Welding
Electron-beam
Laser
(vii)Related Process
Oxy-acetylene cutting
Arc cutting
Hard facing
Brazing
Soldering