1. ELECTRIC ARC WELDING
DEEPAK-KUMAR
C4902A-07

2. Introduction Electric arc welding
A group of fusion welding processes that use an electric arc to produce the heat required for melting the metal.
Electric arc is about 9,000
All fusion welding process have thee requirements.
Heat
Shielding
Filler metal
The method used to meet these three requirements is the primary difference between arc welding processes.

3. Arc Welding Requirements
Filler
Material
Process
Heat
Shielding
Stick
Electrode
SMAW
Electric
Arc
Inert Gas
(Flux)
Electric
Arc
Inert Gas
(Cylinder)
Wire
Electrode
GMAW

4. Arc Welding Power Supplies
The current for arc welder can be supplied by line current or by an alternator/generator.
The amount of heat is determined by the current flow (amps)
The ease of starting and harshness of the arc is determined by the electrical potential (volts).
Welding current adjustments can include:
Amperage
Voltage
Polarity
High frequency current
Wave form

5. Five Common Output Currents For Arc Welding
1. AC (Alternating Current)
2. DC (Direct Current)
3. ACHF (Alternating Current-High Frequency)
4. PC (Pulsed Current)
5. Square wave

6. TYPES OF JOINTS
Five (5) joints:
Corner
Butt
Lap
Edge T

7. 1. Surface Welds
Surface welds are welds were a material has been applied to the surface of another material.
May or may not be blended with the work piece.
Two common applications are for hard surfacing
and padding.

8. 2. Groove Welds
Groove welds are used to fuse the sides or ends of two pieces of metal.
The primary use of groove welds is to complete butt joints.

9. 3. Fillet Welds
Fillet welds have a triangular cross section and are used to fuse two faces of metal that are at a 90 degree angle to each other.
Lap Joint
Outside Corner
T Joint

10. Joints, Welds & Positions Arc Welding Positions
Flat
Horizontal
Vertical Up
Vertical Down
Overhead

11. Weld Nomenclature Bead Penetration Base metal Reinforcement
Joint Angle
Bead
Root Face
Excessive
Penetration
Root Opening

12. Weld Nomenclature-cont.
Reinforcement
Toe
Face
Throat
Leg
Toe
Root
Leg

13. Common Defects and Causes
Description
Cause(s)
The depth of the weld is less than specifications.
Excessive heat
Excessive speed.
The weld metal is not completely fused to base metal or passes are not completely fused.
Incorrect angle
Incorrect manipulation
Insufficient heat
Weld material flows over, but is not fused with the base metal.
Slow speed

14. Common Defects and Causes--cont.
Description
Cause(s)
Weld bead does not extend to the desired depth.
Low heat
Long arc
Incorrect joint design
Small indentions in the surface of the weld
Excessive gas in the weld zone.
Moisture
Rust
Dirt
Accelerated cooling
Small voids throughout the weld material.

15. Common Defects and Causes--cont.
Description
Cause(s)
Usually visible cracks on the surface or through the weld
Accelerated cooling
Constrained joint
Small weld volume
Cracks in the transition zone between the weld and base metal
Induced hydrogen
Incompatible electrode or wire
Accelerated cooling
Misshapen and/or uneven ripples
Inconstant speed
Incorrect manipulation
Incorrect welder settings