PowerPoint Presentation - TIG Welding Introduction

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TUNGSTEN INERT GAS WELDING
(TIG)
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
2
BACKGROUND
• TIG welding uses a non-consumable tungsten
• Filler metal, when required, is added by hand
• Shielding gas protects the weld and tungsten
3
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
4
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
5
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
6
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
7
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
8
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
9
*Figure copied from “TIG Handbook”
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
10
*Figure copied from “TIG Handbook”
TECHNIQUES FOR BASIC WELD JOINTS
Manual Torch Movement
ENBE 499
*Figure copied from “TIG Handbook”
11
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
12
TIG SHIELDING GASES
• Argon
• Helium
• Argon/Helium Mixtures
13
TIG SHIELDING GASES
Helium
Argon
• Good arc starting
• Good cleaning action
• Good arc stability
• Focused arc cone
• Lower arc voltages
• 10-30 CFH flow rates
•
•
•
•
•
•
•
•
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
14
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
15
WELDING PARAMETERS
Aluminum weld parameters
16
*Figure copied from “TIG Handbook”
WELDING PARAMETERS
Stainless steel weld parameters
17
*Figure copied from “TIG Handbook”
WELDING PARAMETERS
Titanium weld parameters
18
*Figure copied from “TIG Handbook”
WELDING PARAMETERS
Mild steel weld parameters
19
*Figure copied from “TIG Handbook”
TUNGSTEN ELECTRODE SELECTION
Guide to selecting a tungsten electrode based on amperage range
20
*Figure copied from “Guidelines to Gas Tungsten Arc Welding (GTAW)”
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