Transcript Gas metal Arc Welding PPT.

Weld Joints
Butt Joint
Corner Joint
Inside
Outside
Edge Joint
T Joint
Lap Joint
Electrode Classification
Electrode #’s
Tensile Strength
Welding Position
Special Characteristics
60 = 60,000 psi
1 = All Positions
0 = Deep/DC + / Fast Freeze
70 = 70,000 psi
2 = Flat/Horizontal
1 = Deep/AC/DC + / Fast Freeze
80 = 80,000 psi
3 = Flat Only
3 = Shallow /AC/DC+/DC-
90 = 90,000 psi
8 = Medium / AC/DC+/Low Hydro
X 1000 lbs sq inch
Tensile Strength
Special Characteristics
•Current Type
•Flux Characteristics
•Metal Type
Electrode
•Penetration
E 60 1 1
Position
E 60 11
60,000 psi
Special Characteristics
•Deep Penetration
•Cellulose Potassium flux
•Fast Freeze
Electrode
•AC/DC+ (current)
E 60 1 1
All Position
E 60 1 0
60,000 psi
Special Characteristics
•Deep Penetration
•Cellulose sodium flux
•Fast Freeze
Electrode
•DC+ (current)
E 60 1 0
All Position
E 70 1 8
70,000 psi
Special Characteristics
•Medium Penetration
•Iron Powder Low Hydrogen flux
•AC/ DC+ (current)
Electrode
E 70 1 8
All Position
E 60 1 3
60,000 psi
Special Characteristics
•Shallow Penetration
•Titania Potassium flux
•AC / DC+ / DC - (current)
Electrode
E 60 1 3
All Position
Electrode #’s Quiz Slide
E
Electrode
80
80,000 psi tensile
strength
2
Flat/Horizontal
Position
1 Deep Penetration
Fast Freeze
AC/DC +
Tensile Strength
Welding Position
Special Characteristics
60 = 60,000 psi
1 = All Positions
0 = Deep/DC + / Fast Freeze
70 = 70,000 psi
Electrode
80 = 80,000 psi
E
90 = 90,000 psi
60
Low +
Hydrogen
Flux
2 = Flat/Horizontal
1 = Deep/AC/DC
/ Fast Freeze
60,000
psi tensile
Flat Position
strength
Medium Penetration
3 = Flat Only
Only 3 = Shallow /AC/DC+/DC+
8 = Medium AC/DC
/ AC/DC+/Low
Hydro
3
8
Welding Terminology
Arc Length





Distance between the tip of the electrode
and the base metal. Also known as Arc
Gap.
Long Arc = large Gap
Short Arc = Small Gap
Shorter the Gap = Cooler the Arc
Longer the Gap = Hotter the Arc
Shielding Gases

Carbon Dioxide (C02)

Co2/Argon Mix (Mixed Gas)



75%/25%
85%/15%
90%/10%
Wire Speed


Speed in Inches Per Minute (IPM) that the
wire spools through lead cable out the
nozzle.
Changes the Amp in the Circuit (Current)
Wire Stick-out


Distance the wire protrudes past electrode
tip/nozzle
Can:



Increase spatter (Too long or short)
Burn tip/wire together (create too much resistance)
Be adjusted to get smooth current (Volts/Amps)
Gun Angle

Angle the Gun/Tip is held from the base
metal

1)Base Angle (BA)

2)Direction of Travel Angle (DOTA)
Forehand/backhand

Forehand: Pushing the puddle


80 Degree Push
Backhand: Dragging puddle

80 Degrees DOT.
Porosity
Gas Pocket in/on the weld that is a defect
in the weld.
Causes:
 Long arc
 Dirty base metal
 Shielding Gas Off (needs to be 20 CF)





Gas Off
To Low of Pressure
To High of Pressure (causes Turbulence)
Wind/Weather
Fusion

Combining or joining of two materials
Non Ferrous=
 Metal
that does not contain Iron
 Example:
Aluminum/Copper, brass,
lead, nickel, tin, titanium
Ferrous Metal

Metal containing Iron

Example: mild steel Metal/Stainless,
carbon steel/AR plate
Welding Electrical Terms
Electrical Terms

12. The arc is extinguished every halfcycle as the current passes through zero,
usually at the rate of 120 times per
second.
Alternating Current

Current (electrons) is traveling in both
directions back and forth.
Current is changing from positive-Negative

Hertz: sign wave electrical current

DC Current

DC: Direct Current

Current is traveling in one direction

Polarity: Changing direction current flows

Ground to Electrode or Electrode to ground
DC Polarity


DC + electrode is Positive and electrons
will flow from neg to pos therefore will go
from neg Ground to positive electrode.
Reverse polarity/DCEP/DC+
DC - Electrode is negative and electrons
will flow from Neg to positive therefore go
to the positive ground clamp.
Straight polarity/DCEN/DC-
Amps




The measure of Electrical Flow
1) electrons traveling
2) Water running out of a garden hose
would be compared to Amps
3) Water Flow/Electrical Flow
Volts




Measure of Electrical Pressure
1) Force of electrons
2) Compared to your finger over a running
garden hose to generate more
pressure.
3) water pressure/Electrical pressure
CC

Constant Current

Amps (Current) stays constant (Vary Slightly)
and there are change in voltage during
welding process.

?? What changes Voltage?

Typical processes: SMAW/GTAW
CV
Constant Voltage
Voltage stays constant (Varies slightly) and
there are changes in Current (Amps) during
welding process.

?? What changes Amperage?

Typical processes: GMAW
Weld Pattern/Movement
Out of position Welding
D. There are four positions used
when welding:

Overhead
D. There are four positions used
when welding:

Horizontal
D. There are four positions used
when welding:

Vertical
D. There are four positions used
when welding:


Flat
The flat position produces welds that are
stronger than in any other position.
Base metal Prep
9. The double V butt joint is
excellent for all load conditions and
is often used on metal sections over
¾ inch in thickness.
7. The single V butt joint is often used
on plate steel 3 /8 inch to ¾ inch in
thickness. This joint is strong in loads
with tension forces but weak in loads
that bend at the weld root. The weld
root is the bottom of the weld groove
opposite the weld face.
8. The single-bevel butt joint is used
on metals from 1/8 inch to ½ inch in
thickness and the bevel is 45
degrees.
4. The plug and slot welds are
used to join pieces that
overlap. The welds are placed
in plug or slot holes. These
types of welds commonly take
the place of rivets in welded
structures.
GMAW Gas Metal Arc Welding
GMAW Spool & Roller Guides
Tensioner
Wire irregularly fed (rat or bird nest)
GMAW Machine/equipment
GMAW Torch Parts
GMAW Shielding Action
GMAW Nozzle/Gun parts
GMAW welding
Flow meter
PAC Plasma Arc Cutting
Brands Of plasma Cutters