1. MY PRESENTATION TOPIC Tungsten Inert Gas(TIG) Metal Inert Gas(MIG)
Resistance Welding
Spot
Projection
seam Submitted By:-
GIRISH KUMAR
(B2)
3rd yrs.
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2. Contents Introduction Techniques advantages Disadvantages Application
Safety
Conclusion
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3. TIG WELDING

4. Introduction What is TIG? Also referred to as GTAW
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

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

6. 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”

7. Techniques for Basic Weld Joints
Gas Cup Size
Inside diameter of gas cup should be at least three times the tungsten diameter to provide adequate shielding gas coverage
Picture on right shows example of gas cup size and torch position
1-Workpiece, 2-Work clamp, 3-Torch, 4-Filler rod, 5-Gas cup, 6-Tungsten electrode
*Figure copied from “TIG Handbook”

8. Techniques for Basic Weld Joints
Electrode Extension
Refers to distance the tungsten extends out beyond the gas cup
May vary from flush with the gas cup to no more than the inside diameter of the gas cup
Longer the extension, the more likely it may contact something by accident
General rule would be to start with an extension of one electrode diameter

9. Techniques for Basic Weld Joints
Butt Weld and Stringer Bead
Be sure to center weld pool on adjoining edges
When finishing a butt weld, torch angle may be decreased to aid in filling the crater
Torch and rod position for welding the butt weld and stringer bead
*Figure copied from “TIG Handbook”

10. Techniques for Basic Weld Joints
Lap Joint
Pool is formed so that the edge of the overlapping piece and the flat surface of the second piece flow together
Torch angle is important because the edge will become molten before the flat surface
Enough filler metal must be added to fill the joint as illustrated on the right
Torch and rod position for welding the lap joint
*Figure copied from “TIG Handbook”

11. Techniques for Basic Weld Joints
T-Joint
Edge will heat up and melt sooner
Torch angle illustrated will direct more heat onto the flat surface
Electrode may need to be extended further beyond the cup in order to hold a short arc
Torch and rod position for welding the T-joint
*Figure copied from “TIG Handbook”

12. Techniques for Basic Weld Joints
Corner Joint
Both edges of the adjoining pieces should be melted and the pool kept on the joint centerline
Sufficient filler metal is necessary to create a convex bead as shown
Torch and rod position for welding the corner joint
*Figure copied from “TIG Handbook”

13. TIG Shielding Gases
Argon
Helium
Argon/Helium Mixtures

14. 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
Helium
Faster travel speeds
Increased penetration
Difficult arc starting
Less cleaning action
Less low amp stability
Flared arc cone
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. Advantages Welds more metals and metal alloys than any other process
High quality and precision
Pin point control
Aesthetic weld beads
No sparks or spatter
No flux or slag
No smoke or fumes

17. 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

18. 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

19. Conclusion
TIG welding is an exciting skill that proves itself useful in countless applications
Because it welds more metal and metal alloys than any other process, TIG welding should be regarded as an important tool where experience is the teacher
Welding parameters and tungsten electrode selection tables are recommended values and should be used as a guideline
Information presented here is only the tip of the iceberg, and further research and hands-on involvement should be pursued to be comprehensive

20. MIG WELDING
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21. Introduction MIG- Metal Inert Gas. Used for thin metals.
Use for high strength metals.
Used for low alloy steels.
It has little or no slag.
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22. Principles and Characteristics
Welding wire is automatically fed at a constant speed.
Arc is generated between the base metal and the wire.
Resulting in heat joining the 2 base metals together.
Process ranges in frequency from 50 to 200 cycles a second.
Mig uses reverse polarity.
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23. Starting the MIG welder
Open the gas valve.
Set the voltage for the arc.
Set the wire speed.
Turn the welder on.
Press the trigger on the gun.
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24. Types of wire feed welders
Gas metal- arc process (MIG)- This system has a continuous feed of solid wire.
Uses on DC current with reverse polarity.
Used a mild steel.
Used on thinner metals.
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25. Gases used to form a shield
Carbon Dioxide.
Argon.
Helium.
Combination of 1,2 and3.
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26. Advantege No flux required. High welding speed.
Increased corrosion resistance.
Easily automated welding.
High economy.
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27. DisAdvantege Higher initial setup cost.
Higher maintenance costs due to extra electronic component.
The setting of plant variables requires a high skill level.
Radiation effects are more server.
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28. RESISTANCE WELDING
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29. General principles
Resistance welding is a thermo- electric process in which heat is generated at the interface of the parts to be joined by passing an electrical current through the parts for a precisely controlled time and under a controlled pressure (also called force).
Process variables
Current, Time, Force.
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30. Working
Resistance welding is a pressure welding technique using high current and low voltage.
In resistance welding the metal parts to be joined are heated to a plastic state over a limited areas by their resistance to the flow of an electric current .
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31. Cont…
Electrode tips wear during service, causing nugget size to decrease.
Zinc- coating on steel alloys with copper electrodes to form brass.
Copper base materials, divided into classes.
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32. Advantege Very short process time. No consumables.
Operator safety because of low voltage.
Clean and environmentally friendly.
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33. Types of resistance welding
There are following types
Spot welding
Projection welding
Seam welding
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37. Disadvantage of spot welding
It can create only localized joins, which may not be particularly strong
The strength of spot weld depend on the force & temperature that has been applied & cleanliness of the electrodes & metal
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43. Disadvantage of projection welding
Production of projection may be more costly.
Close tolerance must be held to obtain acceptable quality.
Weld size is limited by projection size.
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44. THANK YOU
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