1. In Agriculture Systems 1
You will use GMAW Short Circuit Transfer to perform your assigned Weld Joints.

2. Modes of Metal Transfer
GMAW is a process that features several distinctive, individual methods and types of Weld metal transfer.

3. What is a Transfer Mode?
It is How the Weld wire (electrode) moves into and becomes the weld puddle.

4. Welding Variables
The mode of metal transfer is determined by a number of welding variables
Voltage
Amperage
Shielding Gas
By changing one or more variables, you can go from one metal transfer mode to another.

5. The Transfer modes are Short Circuit Transfer 16 to 22 volts
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The Transfer modes are
Short Circuit Transfer
16 to 22 volts
Globular Transfer
22 to 25 volts
Globular Transfer Generates Spatter!
Spray Transfer
25 to 32 volts
Needs an Argon rich shielding gas
Mig Welding Parameters - Weld Voltage
Voltages for Short Circuit transfer are in the range of 16 to 21 volts.
Spray transfer weld voltages run between 25 and 32 volts.
Globular transfer generally occurs between 22 and 25 volts.
With welding parameters, when your given a range to work with always start out in the middle of that range. If you need to make a slight adjustment, do so, but keep it within the range.
Remember - If you commonly weld using voltages between 22 and 25 you are most likely in the Globular transfer mode and generating excessive spatter. Increase or decrease you voltage to attain the proper transfer mode (Short Circuit or Spray).

6. Short Circuit Transfer…
is the transfer mode you will use Ag Systems 1 GMAW welding.
Short circuit transfer refers to the welding wire actually “short circuiting” (touching) the base metal between times per second.

7. The Sound of the Arc A Rapid Smooth Crackle.
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The Sound of the Arc
A Rapid Smooth Crackle.
The crackle is caused by each short circuit.
The higher the frequency (more short circuits) the more consistent the arc.
Short circuit transfer is an Arc On, Arc Off welding process.
The Sound of the Arc
Once you’ve understood the differences between Spray and Short Circuit, you know when to use them and how to set their parameters, you can use your ears to fine tune the arc.
The sound of a Short Circuit transfer weld is a rapid crackle sound. The crackle is caused by each short circuit. The more short circuits per second the more consistent the arc. Your listening for the highest frequency, the most short circuits.
The sound of a Spray transfer weld is a consistent crackle sound.
When voltage is set too high, a quiet “Whooshing” sound can be heard.
If voltage is set too low a harsh, irregular crackle is heard.
The wire is driving into the puddle and spatter increases. Your in Globular transfer and you need to increase voltage to get out.

8. Short - Arc or Short-circuit Transfer
In short-circuit transfer the electrode touches the work and shorts out.
The metal transfers through the Arc as a result of the short.
This happens at a rate of 20 to more than 200 times per second.

9. Short Circuit Transfer
Setting the weld process parameters:
Volts, amps and wire feed rate is critical to maintaining a stable arc: generally between 100 to 200 amperes at 17 to 22 volts for most applications.
More Explained

10. A Versatile metal transfer mode
With short circuit transfer, wire feed speeds, voltages, and deposition rates are usually lower than with other types of metal transfer such as spray transfer.
This makes short circuit transfer very versatile allowing the welder to weld on thin or thick metals in any position.
Versatile & Useful Video Clip

11. Advantages Of Short Circuit Transfer
All-position Welding: including flat, horizontal, vertical-up or down, and overhead.
Handles poor fit-up extremely well.
Lower heat input which reduces weldment distortion.
Higher operator appeal and ease of use.

12. A relatively low deposition rate.
Disadvantages of short circuit transfer compared to other transfer modes:
A relatively low deposition rate.
Lack of fusion, it could cause cold lap on thicker metals.
Can produce more spatter.
Concerns of Short circuit Video Clip

13. Machine set up and Correct operation!
The disadvantages are minimized when correct welder set up and welding procedures and practices are followed.
** Short circuit transfer usually has a crackling (bacon frying) sound when a good condition exists.

14. Short Circuit Cycle described
Follow the steps, A-F, as the cycle happens.
It is pretty cool.

15. Short Circuit Cycle described
A - Electrode is short circuited to base metal. No arc, and current is flowing through electrode wire and base metal.

16. Short Circuit Cycle described
B - Resistance increases in electrode wire causing it to heat, melt and “neck down”.

17. Short Circuit Cycle described
C - Electrode wire separates from weld puddle, creating an arc. Small portion of electrode wire is deposited which forms a weld puddle.

18. Short Circuit Cycle described
D - Arc length and load voltage are at maximum. Heat of arc is flattening the puddle and increasing the diameter tip of electrode.

19. Short Circuit Cycle described
E - Wire feed speed overcomes heat of arc and wire approaches base metal again.

20. Short Circuit Cycle described
F - Arc is off and the short circuit cycle starts again.

21. View Short Circuit Transfer
See it in action
Click on the figure

22. Well Now! Lets see what You know about Welding in Agriculture Systems 1,
DO YOU:
know which Welding Process you are to use in Ag Systems 1…
know which Transfer mode you are to use in Ag Systems 1…
know which Joint designs and positions you are to use in Ag Systems 1…
Gas Metal Arc Welding
Short Circuit transfer
Lets find out!

23. Weld Joints, and Positions.
For Ag systems 1

24. Welding Positions
Welding is often done on structures in the position in which they are found.
Techniques have been developed to allow welding in any position.
Some welding processes have all-position capabilities, while others may be used in only one or two positions.

25. There are four basic welding positions
All welding can be classified according to the position of the workpiece or the position of the welded joint on the plates or sections being welded.
The Face and the geometric center of the weld bead give reference to the position it is in.

26. Types of Welds, Positions, and Joints for Agriculture Systems 1
Fillet Welds
Groove Welds

27. A Tip to help with Joint set up
Tack welds are often used to assist assembly or to maintain edge alignment during welding.

28. Flat position GMAW welding for fillet and groove welds.
A steady motion works well here but any pattern will too as long as the electrode is at the leading edge of the puddle for better weld penetration.

29. Welding In the Flat Position T-Joint
For a fillet weld on a T-joint, keep the gun at a 45 degree angle, or equal distance from each piece. This helps avoid uneven weld beads and undercuts.
The angle of the MIG gun can be pointing straight down to leaning 5°–15° in the direction of travel.

30. Welding In the Flat Position Butt Joint
For a groove weld on a butt joint, hold the gun at a 90 degree angle to the workpiece, directing the filler metal into the joint.
The angle of the MIG gun can be pointing straight down to leaning 5°–15° in the direction of travel.

31. Use a Small Weave or not
A small, back and forth motion with the gun can help fill a large gap or flatten the bead profile.

32. Horizontal Position Welding
A horizontal weld is a bit more tricky than a flat position weld.
Work (gun) angle is very important.

33. Welding in the Horizontal position
The travel angle, whether using a push or a drag technique, remains about the same as for the flat position.
A back-and-forth or slight up-and down weave bead may be used to fill a horizontal position weld joint.
The Horizontal Position

34. Welding a Horizontal Fillet weld
In this position, welding is performed on the upper side of an approximately horizontal surface and against an approximately vertical surface.
45°
Horizontal fillet welds.

35. Welding a Horizontal T-Joint
Voltage and amperage maybe set 10-15% less, than settings for welding in the flat position.
A slight pause at the top edge of the weld helps prevent undercut and ensure proper tie-in of the weld to the base metal.

36. Another Technique
See the yellow line on the weld beads. It looks like a series of little cursive e's or little u's, some what like little loops.

37. 2F
See a clip of horizontal fillet welding: Tee and Lapp joint

38. Welding a Horizontal Groove joint
The effect of Gravity requires you to angle the gun slightly upward toward the top piece of material.
Without changing the work angle, the filler metal may sag or rollover on the bottom edge of the weld joint.

39. Welding a Horizontal Groove joint
Voltage and amperage settings is 10-15% less, than settings for welding in the flat position.
The travel angle, whether using a push or a drag technique, remains about the same as for the flat position.

40. Some Techniques
A slight up-and –down weave bead may be used to help fill a horizontal position groove joint.
A slight pause at the top edge of the weld helps prevent undercut and underfill.

41. Welding a 2G butt joint
In this position, the axis of the weld lies in an approximately horizontal plane and the face of the weld lies in an approximately vertical plane.
To help overcome gravity, the gun must be pointed slightly upward 5°–15° toward the top piece of material.
5°–15°

42. 2G welding
See a clip of Horizontal Groove joint

43. Practice & Practice & Practice
Each individual welder is different, holds the gun a little differently, uses a little different angle, uses different stickout, and uses different wire speed settings.
I am not sure any one GMAW welding technique could be called the best.
Learn and practice several.

44. The techniques that helps you produce quality welds REPEATEDLY is the one you should use!
“When you are not practicing, remember, someone somewhere is practicing, and when you apply for a job against them, they will be harder to beat!”

45. Get the assignment “Weld procedure My recipe for a good weld”.
Fill it out
Complete the weld
DO IT WELL!
Turn it in for evaluation.