Fundamentals Of Mig, Fcaw And Mcaw - Linde BOC RAPTOR 250R MIG Operating Manual

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BOC RAPTOR 200C & 250R MIG Operating manual
Typical Metal Transfer Mode
Process
Metal Inert Gas (MIG)
Metal Active Gas (MAG)
Flux Cored (Gas Shielded)
Flux Cored (Self Shielded)
Metal Cored
* Not True Spray

12.5 Fundamentals of MIG, FCAW and MCAW

Welding Technique
Successful welding depends on the following factors:
1 Selection of correct consumables
2 Selection of the correct power source
3 Selection of the correct polarity on the power source
4 Selection of the correct shielding gas
5 Selection of the correct application techniques
a Correct angle of electrode to work
b Correct electrical stickout
c Correct travel speed
6 Selection of the welding preparation
Selection of Correct Consumable
Chemical composition
As a general rule the selection of a wire is straightforward, in that
it is only a matter of selecting an electrode of similar composition
to the parent material. It will be found, however, that there are
certain applications that electrodes will be selected on the basis
of its mechanical properties or level of residual hydrogen in the
weldmetal. Solid MIG wires are all considered to be of the 'low
Hydrogen type' consumables.
The following table gives a general overview of the selection
of some of the BOC range of MIG wires for the most common
materials.
Common Materials Welded with BOC MIG Wire
Material
AS2074 C1,C2,C3, C4-1,C4-2,C5,C6
BS3100 AW1,A2,A3
BS1504-430,480,540
Dip Globular
Transfer Transfer
✓ ✗
✓ ✓
✓ ✓
✓ ✗
BOC MIG Wire
BOC Mild Steel MIG Wire
BOC Mild Steel MIG Wire
BOC Mild Steel MIG Wire
Cast and Helix
Spray
Transfer
✓
✓*
Cast – Diameter of the circle
Helix – Vertical height
✗
✓
Common Materials Welded with BOC MIG Wire
Material
ASTM A36,A106,EN8,8A
Stainless Steel
Grade 304
Grade 309
Grade 316
Physical condition
Surface condition
The welding wire must be free from any surface contamination
including mechanical damage such as scratch marks.
A simple test for checking the surface condition is to run the wire
through a cloth that has been dampened with acetone for 20 secs.
If a black residue is found on the cloth the surface of the wire is not
properly cleaned.
Cast and Helix
The cast and helix of the wire has a major influence on the
feedability of MIG wire.
If the cast is too large the wire will move in an upward direction
from the tip when welding and if too small the wire will dip down
from the tip. The result of this is excessive tip wear and increased
wear in the liners.
If the helix is too large the wire will leave the tip with a
corkscrew effect.
Cast
BOC MIG Wire
BOC Mild Steel MIG Wire
BOC Stainless Steel 308LSi
BOC Stainless Steel 309LSi
BOC Stainless Steel 316LSi
Helix