GMAW / Mig Welding - PowerPoint PPT Presentation

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GMAW / Mig Welding

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GMAW / Mig Welding Basic equipment setup and welding procedures Gas Metal Arc Welding Is a process where a continuously fed metal electrode ( Wire ) contacts the base ... – PowerPoint PPT presentation

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Title: GMAW / Mig Welding


1
GMAW / Mig Welding
  • Basic equipment setup and welding procedures

2
Gas Metal Arc Welding
  • Is a process where a continuously fed metal
    electrode ( Wire ) contacts the base metal and
    produces heat . The arc is shielded by an inert
    gas

3
GMAW Components
  • DC or Direct Current power supply
  • Electrode or wire feed controller
  • Wire drive roller assembly
  • Shielding gas source (cylinder) regulator
  • Manually held Gun ground clamps
  • Wire reel

4
GMAW component diagram
5
Gas Metal Arc Welding Principles
  • Gas metal arc welding is generally used due to
    the high efficiency of filler metal that can be
    deposited per hour.
  • GMAW is approximately 92 - 98 efficient
  • GMAW requires a shielding gas

6
Gas Metal Arc Welding Principles
  • The GMAW process is performed using DCEP ( Direct
    Current Electrode Positive)
  • Alternating current is never used for GMAW
  • DCEN is used only for a specialized process
    using emissive electrodes

7
GMAW Advantages
  • Welding can be done in all positions
  • No slag removal required
  • High efficiency
  • Less work piece distortion
  • Large gaps bridged easily , Good for poor fitup
  • High Weld Quality

8
Typical Setup for voltage
  • The GMAW machine is a Constant Voltage power
    supply. This is set using the voltage dial
  • This setting can be monitored by the Volt meter
    on the front panel of the welder
  • Ideal voltage settings can be found in the wire
    manufactures data book

9
Typical Setup for Wire speed
  • The wire feed rate or speed is set using the dial
    on the wire controller This setting increases or
    decreases current or Heat. This setting is
    measured in AMPS or IPM (inches per minute )
  • Ideal settings can be monitored by the Amp
    meter on the front panel of the welder. Note
    Some machines display Current (Same as AMPS)
    or IMP
  • Ideal settings can be found in the wire
    manufactures data book for both IPM and Current

10
Shielding Gas
  • Air in the welding zone is displaced by inert gas
    to Shield the molten weld pool and prevent it
    from contamination from Oxygen, Nitrogen and
    Water present in the atmosphere.
  • Insufficient gas flow will not displace the
    atmosphere resulting in porosity or voids in
    the deposited weld.
  • Flow is measured in CFH (Cubic Feet per Hour).

11
Insufficient Shielding Gas coverage
  • Gas not turned on
  • Flow rate not properly adjusted
  • Leaks in the hose supplying the shielding gas to
    the machine
  • GMAW / MIG Gun loose at wire drive connection
  • Spatter buildup on gas cup
  • Windy environment

12
Excessive Gas coverage
  • Will cause porosity.
  • The turbulence caused by the rapid flow of
    shielding gas exiting from the gas cup will draw
    the surrounding atmosphere into the stream of
    gas.
  • It will reduce weld pool temperatures causing
    decreased penetration .

13
Check the Manufactures data for settings
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