– 4 –
3.2 Selection of Collet, Collet Body
A collet and a collet body are for feeding and holding electrode. They are divided into two kinds
depending on whether they have gas lenses. (Ones for gas lenses are incorporated as standards.)
Moreover, they are divided into four kinds depending on the electrode diameter to be used with, thus
use a right collet and a collet body according to electrode diameter.
3.3 Selection of Nozzle
In order to have a sufficient shielding effect of argon gas, see Table 5 and use a right nozzle according
to welding current.
Nozzles have good electric insulation, and they especially have excellent shock-resistance and
heat-resistance.
The relationship between welding current and nozzle diameter is described in Table 5, and the
relationship between nozzle No. and inside diameter in Table 6.
Table 5 The Relationship between Welding Current and Nozzle Diameter
DC welding
AC welding
Welding
current (A)
Nozzle No.
Gas flow rate
Nozzle No.
Gas flow rate
10 – 100
4, 5, 6
4 – 5 liter / min
5, 6
6 – 8 liter / min
101 – 150
4, 5, 6
5 – 7 liter / min
6, 7
7 – 10 liter / min
151 – 200
4, 5, 6, 7, 8
6 – 8 liter / min
7, 8
7 – 10 liter / min
201 – 300
5, 6, 7, 8
8 – 9 liter / min
8, 10, 12
8 – 15 liter / min
Table 6 The Relationship between Nozzle No. and Inside Diameter
Nozzle
No.
4 5 6 7 8 10
12
Inside diameter (mm)
6.5
8
9.5
11
12.7
16
19
3.4 Nozzle for Gas Lens
When a fluid flows inside a tube, the bigger the value of L/D is,
the easier it is to obtain the streamline flow.
(L: length of a tube, D: diameter of a tube)
Gas lens has this logic applied.
●
As gas is spouted from a nozzle in a streamline flow, it has
good shield effect.
●
Even a small gas flow rate brings about sufficient shield effect.
●
As the length of the tip of tungsten is adjustable, more space between a nozzle and a workpiece can
be obtained. That makes it easier for personnel to observe arc and the working area well.
Moreover, welding in a narrow area will be feasible.
●
The productivity will rise and the damage to a nozzle will be far reduced. Therefore, a gas nozzle is
very useful in high-quality or complicated welding.
∗
When you do not use a nozzle for a gas lens, you do not need No. 3: Insulator (H21B60) in the Parts
List on pp.8.
Gas lens controls the flow of shield gas at a uniform pace.
Gas lens has the following advantages.
This length is
adjustable.
5 to 7 times longer
than usual
