New update from the Dinamitek welding school

Dinamitek presents a guide on MIG MAG welding and welding wire

Let's go back to a basic concept of MIG MAG welding, because a refresher is useful even for the most experienced, but above all, these notions are fundamental for those who are just starting to experiment with welding.

We want to talk about welding wires, the technique used is MIG MAG WELDING

MIG MAG stands for CONTINUOUS WIRE ARC WELDING.

Arc welding can be done

• WITH GAS PROTECTION (GMAW GAS METAL ARC WELDING)
• WITHOUT GAS PROTECTION (FLUX OR SELF SHIELDED WIRE)

MIG and MAG mean two different welding processes:

• MIG (Metal-arc Inert Gas)
• MAG (Metal-arc Active Gas)

The two processes differ in the gas used to shield the weld pool. This process is called continuous wire welding.
To proceed with MIG MAG welding it is necessary to know something more about welding wires.
What characterizes the welding wire is its chemical composition.

The morphology of the wire section is also important:

1. solid wire : section made of metal only
2. cored wire : wire with an internal core containing granules

See all available welding wire spools

a. The solid wire is chosen to be made of the same substance to be welded ; it must have the same chemical composition to be effective.
In addition, the wire contains elements that help clean the material being welded.

b. The flux-cored wire performs the same function as the coated electrode.
Flux-cored wire has a gas shield; the center of the wire is filled with granular powder—flux. Because it acts as a coated electrode, it can be rutile, basic, or a special type.

The Telwin 802975 flux cored wire reel
has a diameter of 0.8 mm,
weight of 0.8 kg.
The thread is very soft and easy to use.

As with all welding, the goal is to prevent the molten metal from oxidizing while welding. Flux-cored wire can be used to weld thin layers because it operates at low amperage. For high amperage, solid wire combined with a shielding gas is used. This allows for welding even thicker layers.

To choose the diameter of the solid wire, orient yourself towards the most common measurements:
0.6 - 0.8 - 0.9 - 1 - 1.2 - 1.6 mm.

For choosing the diameter of the cored wire, the most common measurements are:
0.6 - 0.8 - 0.9 - 1.2 - 1.6 mm.

Users provide a reference measurement to use:

Wires with a diameter of 0.8 mm or 0.9 mm are used to weld pieces with a thickness of 2 mm to 5-6 mm.

The welding machine manuals report this diagram

WELDABLE THICKNESSES

With cored wire Ø 0.9 = 0.8 ÷ 5 mm.
With aluminium wire Ø 0.8 = 1 ÷ 3 mm.
With solid wire (AR CO2) Ø 0.6 = 0.6 ÷ 5 mm.
With solid wire (AR CO2) Ø 0.8 = 1 ÷ 5 mm.
With solid wire Ø 0.6 INOX = 1 ÷ 3 mm.

It should not be forgotten that the thickness of the wire is also influenced by the intensity of the current required to perform the welding.
How to choose between solid wire and flux-cored wire?
Flux-cored wire offers greater arc stability and allows for deeper penetration into the weld pool. The joint will have a more aesthetically pleasing appearance. Welding almost always requires no finishing work, such as the classic spatter grinding. The weld is unlikely to have defects such as porosity. Flux-cored wire, however, requires slag removal, just like in MMA welding .

What shielding gas is used?
• CO2 is suitable for weld seams that penetrate steel.

• The CO2 may be too hot for the thin metal.

• For fine steel a mixture of 75% Argon and 25% CO2 is used.

• Argon is used to weld aluminum.

• For stainless steel you can use the mixture Helium + Argon + CO2.

Suggested use:

The wire must be free of grease or moisture. These substances promote welding conditions that generate cracks, porosity, and blowholes.

Check that the winding is uniform to ensure smooth feed and a stable weld.

For welding with flux-cored wire , adjust the wire output speed onto the metal support to be welded in proportion to the current intensity (taking into account the thickness of the wire) to have a continuous and flawless weld.

Flux-cored welding is performed indoors . It is not performed in an open construction site because the wind disperses the protective "core," affecting the quality of the weld.

For best control of your weld bead, hold the wire directly to the leading edge of the weld bead.

When making continuous welds (vertical, horizontal, or overhead welds), keep the weld spot smaller for better control. Use the shortest possible wire diameter.

Go to the welding range

Notes

• With wire welding it is possible to:
also weld aluminum and stainless steel
welding thin sheets
work continuously

• With flux cored wire welding
They can weld iron and steel (not stainless steel)
the wire feed speed must be precisely adjusted
the torch must be tilted with respect to the welding plane by 35° outwards with respect to the vertical plane
the torch must pass through the joint line and be inclined at 75° towards the direction of the bead's advancement
the advancement must be from right to left to obtain correct protection of the weld pool.

Ask our specialized technician for the wire spool and
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