1. Tungsten inert gas welding (tig)

2. Background What is TIG? Tungsten Inert Gas Also referred to as GTAW
Gas Shielded Tungsten Welding
In TIG welding, a tungsten electrode heats the metal you are welding and gas (most typically Argon) protects the weld from airborne contaminants

3. Background TIG welding uses a non-consumable tungsten
Filler metal, when required, is added by hand
Shielding gas protects the weld and tungsten

4. Advantages Welds more metals and metal alloys than any other process
High quality and precision
Aesthetic weld beads
No sparks or spatter
No flux or slag
No smoke or fumes

5. Disadvantages Lower filler metal deposition rates
Good hand-eye coordination a required skill
Brighter UV rays than other processes
Slower travel speeds than other processes
Equipment costs tend to be higher than other processes

6. Safety Electric shock can kill.
Always wear dry insulating gloves
Insulate yourself from work and ground
Do not touch live electrical parts
Keep all panels and covers securely in place
Fumes and gases can be hazardous to your health.
Keep your head out of the fumes
Ventilate area, or use breathing device

7. Safety Welding can cause fire or explosion.
Do not weld near flammable material
Watch for fire; keep extinguisher nearby
Do not locate unit over combustible surfaces
Do not weld on closed containers
Arc rays can burn eyes and skin; Noise can damage hearing.
Wear welding helmet with correct shade of filter
Wear correct eye, ear, and body protection

8. Safety Hot parts can cause injury.
Allow cooling period before touching welded metal
Wear protective gloves and clothing
Magnetic fields from high currents can affect pacemaker operation.
Flying metal can injure eyes.
Welding, chipping, wire brushing, and grinding cause sparks and flying metal; wear approved safety glasses with side shields

9. Techniques for Basic Weld Joints
Arc Length
Arc length normally one electrode diameter, when AC welding with a balled end electrode
When DC welding with a pointed electrode, arc length may be much less than electrode diameter
*Figure copied from “TIG Handbook”

10. Techniques for Basic Weld Joints
Arc Starting with High Frequency
Torch position on left shows recommended method of starting the arc with high frequency when the torch is held manually
By resting gas cup on base metal there is little danger of touching the electrode to the work
After arc is initiated, torch can be raised to proper welding angle
*Figure copied from “TIG Handbook”

11. Techniques for Basic Weld Joints
Manual Torch Movement
ENBE 499
*Figure copied from “TIG Handbook”

12. Techniques for Basic Weld Joints
Manual Torch Movement
Torch and filler rod must be moved progressively and smoothly so the weld pool, the hot filler rod end, and the solidifying weld are not exposed to air that will contaminate the weld metal area or heat affected zone
When arc is turned off, postflow of shielding gas should shield the weld pool, electrode, and hot end of the filler rod

13. Argon/Helium Mixtures
TIG Shielding Gases
Argon
Helium
Argon/Helium Mixtures

14. Helium Argon TIG Shielding Gases Good arc starting
Good cleaning action
Good arc stability
Focused arc cone
Lower arc voltages
10-30 CFH flow rates
Helium
Faster travel speeds
Increased penetration
Difficult arc starting
Less cleaning action
Less low amp stability
Higher arc voltages
Higher flow rates (2x)
Higher cost than argon

15. TIG Shielding Gases Argon/Helium Mixtures
Improved travel speeds over pure argon
Improved penetration over pure argon
Cleaning properties closer to pure argon
Improved arc starting over pure helium
Improved arc stability over pure helium
Arc cone shape more focused than pure helium
Arc voltages between pure argon and pure helium
Higher flow rates than pure argon
Costs higher than pure argon

16. Welding Parameters Aluminum weld parameters
*Figure copied from “TIG Handbook”

17. Welding Parameters Stainless steel weld parameters
*Figure copied from “TIG Handbook”

18. Welding Parameters Titanium weld parameters
*Figure copied from “TIG Handbook”

19. Welding Parameters Mild steel weld parameters
*Figure copied from “TIG Handbook”

20. Tungsten Electrode Selection
Guide to selecting a tungsten electrode based on amperage range
*Figure copied from “Guidelines to Gas Tungsten Arc Welding (GTAW)”