Download presentation
Published byJulissa Battey Modified over 10 years ago
1
ESAB University & Florence-Darlington Technical College
GMAW Fundamentals Gas Metal Arc Welding Metal Inert Gas By: Wanda Sue Benton ESAB University & Florence-Darlington Technical College
2
Introduction GMAW is defined as arc welding using a continuously fed consumable electrode and a shielding gas. GMAW is also known as MIG (Metal Inert Gas). Produces high-quality welds Yields high productivity
3
Advantages Large gaps filled or bridged easily
Welding can be done in all positions No slag removal required High welding speeds High weld quality Less distortion of work piece
4
Types of Metal Transfer
The basic GMAW process includes three distinctive process techniques: Short Circuit (Short Arc) Globular Transfer Spray Arc Transfer
5
Short Circuit (Short Arc)
Operates at low voltages and welding current Small fast-freezing weld puddle obtained Useful in joining thin materials in any position, as well as thick materials in vertical and overhead positions Metal transfer occurs when an electrical short circuit is established
6
Globular Transfer Welding current and wire speed are increased above maximum for short arc Droplets of metal have a greater diameter than the wire being used Spatter present Welding is most effectively done in the flat position when using globular transfer
7
Spray Arc Transfer Occurs when the current and voltage settings are increased higher than that used for Globular Transfer Used on thick sections of base material, best suited for flat position due to large weld puddle Spatter is minimal to none
8
Manual GMAW Equipment Three major elements are :
1.) Welding torch and accessories 2.) Welding control & Wire feed motor 3.) Power Source GMAW equipment can be used either manually or automatically
9
WIRE CONTROL & WIRE FEED MOTOR POWER SOURCE
10
Welding Torch & Accessories
The welding torch guides the wire and shielding gas to the weld zone. Brings welding power to the wire also Major components/parts of the torch are the contact tip, shielding gas nozzle, gas diffuser, and the wire conduit
11
GAS DIFFUSER NOZZLE TRIGGER CONTACT TIP INSTALLED COMPONENTS
12
Welding Control & Wire Feed Motor
Welding control & Wire feed motor are combined into one unit Main function is to pull the wire from the spool and feed it to the arc Controls wire feed speed and regulates the starting and stopping of wire feed Wire feed speed controls Amperage
13
WIRE FEEDER
15
Power Source Almost all GMAW is done with reverse polarity also known as DCEP Positive (+) lead is connected to the torch Negative (-) lead is connected to the work piece Provides a relatively consistent voltage to the arc Arc Voltage is the voltage between the end of the wire and the work piece
16
POWER SOURCE POSITIVE TERMINAL NEGATIVE TERMINAL
17
Shielding Gases Purpose of shielding gas is the protect the weld area from the contaminants in the atmosphere Gas can be Inert, Reactive, or Mixtures of both Gas flow rate is between CFH Argon, Helium, and Carbon Dioxide are the main three gases used in GMAW
18
FLOW METER CFH PRESSURE ADJUSTMENT KNOB CYLCINDER PRESSURE GAUGE
Similar presentations
© 2024 SlidePlayer.com. Inc.
All rights reserved.