MY PRESENTATION TOPIC Tungsten Inert Gas(TIG) Metal Inert Gas(MIG) Resistance Welding Spot Projection seam Submitted By:- GIRISH KUMAR 1214340066(B2) 3rd yrs. ENBE 499

Contents Introduction Techniques advantages Disadvantages Application Safety Conclusion ENBE 499

TIG WELDING

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

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

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”

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”

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

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”

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”

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”

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”

TIG Shielding Gases Argon Helium Argon/Helium Mixtures

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

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

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

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

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

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

MIG WELDING ENBE 499

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. ENBE 499

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. ENBE 499

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. ENBE 499

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. ENBE 499

Gases used to form a shield Carbon Dioxide. Argon. Helium. Combination of 1,2 and3. ENBE 499

Advantege No flux required. High welding speed. Increased corrosion resistance. Easily automated welding. High economy. ENBE 499

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. ENBE 499

RESISTANCE WELDING ENBE 499

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. ENBE 499

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 . ENBE 499

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. ENBE 499

Advantege Very short process time. No consumables. Operator safety because of low voltage. Clean and environmentally friendly. ENBE 499

Types of resistance welding There are following types Spot welding Projection welding Seam welding ENBE 499

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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 ENBE 499

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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. ENBE 499

THANK YOU ENBE 499