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Idiomas disponibles
Idiomas disponibles
Safety in the use of gases (welding with TIG or MIG inert gases)
Compressed gas cylinders
Compressed gas cylinders are potentially dangerous. Refer to suppliers for proper handling procedures:
- No impact: secure the cylinders and keep them away from impacts.
- No excess heat (over 50°C)
Pressure relief valve
- Check that the pressure relief screw is slackened off before connecting to the cylinder.
- Check that the union is tight before opening the valve of the cylinder. Open it slowly a fraction of a turn.
- If there is a leak, NEVER tighten a union under pressure, but first close the valve on the cylinder.
- Always check that hoses are in good condition.
2. MMA WELDING (coated electrode)
To stablish a welding electric arc, a difference of potential must be
inducted between the electrode and the workpiece.
The air between them becomes ionized and conductive, so that the
circuit is closed and an electric arc is created. The heat of the arc
partially melts the base material and the electrode to be deposited
creating a welding seam.
Arc welding is very common due to the low cost of the equipments
and the consumables used in this process.
The metal core of electrode is coated with a flux material that while
merging creates a protective atmosphere that prevents the oxidation
of the molten metal and facilitates the welding operation.
On DC power sources (rectifiers) the polarity of the electric current
affects the metal transfer mode. Typically, the electrode is connec-
ted to the positive (+), although in very thin materials it can be con-
nected to the negative (-).
Despite the favorable welding position is horizontal, this process allows its use at all positions.
MMA welding parameter chart:
Electrode Diameter
Æ 2,5 mm
Æ 3,2 mm
Æ 4,0 mm
Æ 5,0 mm
Æ 6,0 mm
Æ 8,0 mm
Welding current
40 – 125 A
75 – 185 A
105 – 250 A
140 – 305 A
210 – 430 A
275 – 450 A
Electrode holder
Coated electrode
Metal transference
Welding piece
Welding zone
Plate thickness
> 2 mm
> 3 mm
> 6 mm
> 9 mm
> 9 mm
> 9 mm
Arc protection
athmosphere
Earth clamp
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