Jasic MIG SERIES - Guide to TIG Welding; DC Welding Principles; TIG Welding Techniques; TIG Welding Amperage Guide

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GUIDE TO TIG WELDING
Before starng any welding acvity ensure that you have suitable eye protecon and
protecve clothing. Also take the necessary steps to protect any persons within the welding
area.
DC welding
Direct current welding is when the current ows in one direcon only. Compared with AC welding the
current once owing will not go to zero unl welding has ended.
The Jasic TIG Series polarity should generally be set up for Direct Current - Electrode Negave (DCEN) as
this method of welding can be used for a wide range of materials.
The TIG welding torch is connected to the negave output of the machine
and the work return cable to the posive output.
When the arc is established the current ows in the circuit and the heat
distribuon in the arc is around 33% in the negave side of the arc (the
welding torch) and 67% in the posive side of the arc (the work piece).
This balance gives deep arc penetraon of the arc into the work piece
and reduces heat in the electrode.
This reduced heat in the electrode allows more current to be carried by
smaller electrodes compared to other polarity connecons. This method of connecon is oen referred
to as straight polarity and is the most common connecon used in DC welding.
TIG welding techniques
• Before welding (especially with mild steel) you should ensure all material being welded are clean, as
parculates can weaken the weld
• The torch angle is best kept at 15 - 20° (from vercal) away from the direcon of travel. This assists
with visibility of the weld area and allows easier access for the ller material
• The ller metal should be fed in at a low angle to help avoid touching the tungsten electrode and
contaminang it
• The TIG welding arc melts the base material and the molten puddle melts the ller rod, it is
important you resist the urge to melt the ller material directly into the welding arc
• For thinner sheet materials, a ller material may not be needed
• Prepare the tungsten correctly, using a diamond grinding wheel will give you the best results for a
sharp point see page 36
• For welding stainless steel, be careful of applying too much heat. If the colour is dark grey and looks
dirty and heavily oxidized then too much heat has been applied, this could also cause the material
to warp. Reducing the amperage and increase travel speed may correct this problem, you could also
consider using a smaller diameter ller material, as that will require less energy to melt
TIG welding amperage guide
Base Metal
Thickness
Mild Steel
DC Current
Stainless Steel
DC Current
Tungsten Elec-
trode Diameter
Filler Wire Diameter
(If required)
Argon Gas
Flow Rate
(Litres/Min)
Joint Types
1.0mm 40-50 25-35 1.0mm 1.6mm 5-7 Bu/Corner/Fillet/Lap
1.2mm 50-60 35-50 1.0mm 1.6mm 5-7 Bu/Corner/Fillet/Lap
1.6mm 70-90 50-70 1.6mm 1.6mm 6-8 Bu/Corner/Fillet/Lap
3.2mm 90-115 90-110 1.6mm 2.4mm 7-9 Bu/Corner/Fillet/Lap
4.8mm 140-165 125-150 2.4mm 3.2mm 10-12 Bu/Corner/Fillet/Lap
6.4mm 170-200 160-180 3.2mm 4.0mm 10-12 Bu/Corner/Fillet/Lap