Introduction to practical application of wire feed welding

1. Mig Welding Introduction to practical application of wire feed welding

2. MIG – Metal Inert Gas Welding • May be called GMAW (Gas Metal Arc Welding) • Avoid cutting in drafty or windy conditions • Molten pool is shielded by the inert gas envelope • Joints are stronger, more ductile, and more corrosion resistant • Flux center wire has slag; Solid wire has no slag, thus eliminating slag inclusion • Welded metal does not readily distort

3. Tools of the trade • Power Supply • Gas Supply • Wire feeder • Gun and Whip • Process

4. MIG Machine Operation • Wire is fed at a pre-set rate • Gas flows at about 35 cubic feet per hour and is directed around the welding wire for shielding

5. Welding can be done in all positions High rates of metal deposition Excellent filling ability for poor-fit joints High weld Quality No electrode stub loss Less distortion due to narrow, deep weld profile Easier process to learn and use Welding power source expensive Shielding gas expensive Higher electrode wire cost Most machines require three-phase input power Not as versatile as SMAW for maintenance Welding cast iron Cutting Carbon arc torch applications GMAW Process Advantages Disadvantages

6. Stationary Portable Integrated Nonintegrated Advantages and Disadvantages Adjustments Power Supply

7. Containers Regulators Ball and Dial indicators Gases Materials Carbon dioxide Steel Argon Stainless Steel Helium Aluminum Oxygen Gas Supply

8. Types Integrated Component Advantages Disadvantages Parts Feed motor Drive Assembly Spool Assembly Wire speed control Computer controller Wire Feeder

9. Gun Types Inline Handle Gun Characteristics Wire Guide Tips Shielding Gas Nozzle Insulator Internal Gun wire driver Whip Characteristics Shielding Gas Sheath Liner Power feed Gun and Whip

10. Wire Types Hard Wire (Solid) Dual Shield Flux Core Polarity DCRP DCSP Advantages Disadvantages Advantages Disadvantages MIG Welding Process

11. TIG – Tungsten Inert Gas Welding

12. TIG • Welding process uses a non-consumable tungsten electrode to form an arc which is shielded by inert gas • Filler rod may or may not be used • AC or DC • Argon or Helium gas used • Torch needs current and inert gas to weld • Ceramic cone protects electrode • Air cooled or water cooled

13. Advantages of TIG • Clean welds – no flux • Weld strength is high • All position use • Visibility is high • Narrow beads – distortion is low • No Spatter • Weld all weldable metals • Best for Aluminum and Magnesium • Best for thinner metal

14. Disadvantages of TIG • Skill required – more complicated • High Frequency interference may occur (radios, TV’s, etc.)

15. Argon Cheap – comes from air Heavier than air – blankets weld well Provides clean welding of Aluminum and Magnesium Best with AC Helium Arc voltage is greater Hotter arc Deeper Penetration Fast Speed Less Distortion May spatter more than Argon Carbon Dioxide Cooling effect Low cost Produces Spatter Deep penetration Not same inert characteristics as Argon and Helium Inert Gases for Shielding