Introduction to practical application of wire feed welding.

Introduction to practical Introduction to practical

application of wire feed weldingapplication of wire feed welding

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

Power Supply

Gas Supply

Wire feeder

Gun and Whip

Process

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

Advantages Disadvantages 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

Stationary

Portable

Integrated

Nonintegrated

Advantages and

Disadvantages

Adjustments

Containers Regulators

Ball and Dial indicators

Gases Materials Carbon dioxide Steel Argon Stainless Steel Helium Aluminum Oxygen

Types Integrated

Component

Advantages

Disadvantages

Parts Feed motor

Drive Assembly

Spool Assembly

Wire speed control

Computer controller

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

Wire Types Hard Wire (Solid) Dual Shield Flux Core

Polarity DCRP DCSP

Advantages Disadvantages

Advantages Disadvantages

TIG – Tungsten Inert Gas Welding

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

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

Disadvantages of TIG

Skill required – more complicated High Frequency interference may occur

(radios, TV’s, etc.)

Inert Gases for Shielding 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