Define the following terms used in welding.

1. Welded Joint
2. Overhead welding
3. Edge preparation
4. Slag
5. Flux

Mumbai University > Mechanical Engineering > Sem 3 > Production Process 1

Marks: 5M

Year: May 2015

1. Welded Joint

   It is a process of joining of two or more pieces of metal or plastic, by melting and joining them either by the application of heat or without heat, with or without the application of pressure, or both.

2. Overhead welding

   Overhead welding is performed from the underside of a joint. In overhead welding, the metal deposited tends to drop or sag on the plate, causing the bead to have a high crown. To overcome this difficulty, the molten puddle should be kept small, and enough filler metal should be added to obtain good fusion with some reinforcement at the bead.

1. Edge preparation

   In order to have good penetration of the filler material and good welding strength, generally weld edge preparation has to be done. Factors which influence edge preparation are

2. Thickness of weld materials to be joined
3. Material
4. Welding process
5. Extent of penetration required
6. Welding distortion

7. Cost

8. Slag

   Slag is a byproduct of some arc welding processes, most specifically shielded metal arc welding , submerged arc welding, and flux –cored arc welding. Slag is formed when flux, the solid shielding material used in the welding process, melts in or on top of the weld zone. Slag is solidified remaining flux after the weld area cools.

9. Flux

   Welding flux is the combination of carbonate and silicate materials used in the welding processes to shield the weld from atmospheric gases. When the heat of the weld zone reaches the flux, the flux melts and outgases. The gases produced push the atmospheric gas back, preventing oxidation (and reactions with nitrogen).