Tig Welding; Mig-Mag Welding - Telwin SUPERIOR 630 CE VRD Manual De Instrucciones

The welding machine is also equipped with HOT START and ANTI STICK devices to
guarantee easy starts and to prevent the electrode from sticking to the piece.
6.1.1 Procedure
- Keeping the mask IN FRONT OF YOUR FACE, rub the tip of the electrode on the
piece to be welded, moving as if striking a match; this is the most correct method for
igniting the arc. With the VRD enabled, the arc ignites when the electrode is placed
in contact with the workpiece and then quickly removed.
CAREFUL: DO NOT TAP the electrode against the workpiece, which could damage
the coating and make arc striking difficult.
- As soon as the arc has struck, try to keep the electrode at a distance from the
workpiece that is equivalent to the diameter of the electrode being used, and keep
this distance as constant as possible while welding; remember that the electrode
angle while moving forward must be approx. 20-30 degrees.
- At the end of the welding seam, take the electrode end slightly back as to the
forward direction, above the crater to fill it, then quickly lift the electrode from the
weld pool to switch off the arc (Aspects of the welding seam - FIG. M).

6.2 TIG WELDING

TIG welding is a process that uses the heat produced by the electric arc that is struck
and maintained between a non-fusible electrode (Tungsten) and the piece to be
welded. The Tungsten electrode is supported by a torch that is suitable for transmitting
the welding current and protecting the electrode and the weld pool from atmospheric
oxidation with a flow of inert gas (normally Argon: Ar 99.5%) that exits from the ceramic
nozzle (FIG. G).
For the welding to be good, the exact diameter of the electrode must be used with the
exact current, see table (TAB. 3).
The electrode normally projects from the ceramic nozzle by 2-3 mm, but can reach 8
mm for welding edges.
The weld is created by the edges that melt. Welding material (FIG. H) is not required
for a suitably prepared thinness (up to approx. 1 mm).
A greater thickness requires rods made from the same material as the basic material
and with a suitable diameter, with edges that have been suitably prepared (FIG. I). For
welding to be successful, the pieces must be carefully cleaned and free from oxide,
grease, oil, solvent, etc.
6.2.1 LIFT strike
Ignite the arc, distancing the tungsten electrode from the workpiece. Igniting in this
manner causes less electric-irradiated disturbances and reduces tungsten inclusions
and electrode wear to a minimum.
6.2.2 Procedure
- Place the tip of the electrode against the workpiece, applying slight pressure; raise
the electrode by 2-3 mm after a few seconds to ignite the arc. The welding machine
begins by supplying an I current, and after this it supplies the set welding current.
LIFT
- Adjust the welding current to the required value using the encoder knob (FIG. D (8));
if necessary adjust during welding to the true thermal ratio that is required.
- Make sure the gas is flowing correctly from the torch.
6.2.3 TIG DC welding
TIG DC welding is suitable for all types of low-alloy and high carbon steel, and heavy
metals such as copper, nickel, titanium and their alloys.
To TIG DC weld with electrode at the (-) pole, an electrode with 2% Thorium (red band)
or an electrode with 2% Cerium (grey band) is normally used.
The tungsten electrode must be positioned axially to the grinding wheel, see FIG. L,
making sure that the tip is perfectly concentric to prevent arc deviations. The electrode
must be ground along its length. This operation must be repeated periodically
according to the use and wear state of the electrode, or when the electrode itself has
been accidentally contaminated, oxidised or used incorrectly.
Table (TAB. 3 shows approximate data for TIG DC welding.
6.3 GOUGING
The GOUGING process uses an electric arc that gouges between a relative carbon
electrode coated with a thin layer of copper and supplied with direct current, and the
piece to be gouged; the arc locally melts the metal, which is removed by a jet of
compressed air. In order to gouge, there must be a suitable clamp for the electrode
that is connected to the positive pole of the generator and a valve that controls the
compressed air. The carbon electrode is fixed to the clamp with a projection of 70 - 150
mm and is kept at approx. 45° as to the piece to be cut. This angle can be reduced
to 20°. The gouging depth depends on this angle and on the forward speed of the
electrode.
The edges remain coated by a layer of oxides and carbon, which must be eliminated
by grinding.
This process can also be used for cutting sheets, even if the edges obtained are not
very regular.
The gouging current is adjusted according to the diameter of the electrode used.
Indicatively, the currents that can be used for the various electrode diameters are:
Welding current (A)
Ø Electrode
(mm)
Min.
4 90
5 200
6.4 300
8 350
10 450

6.4 MIG-MAG WELDING

6.4.1 SHORT ARC TRANSFER MODE
The melting of the electrode wire and the detachment of the drop is produced by
repeated short circuits (up to 200 times per second) from the tip of the wire to the
molten pool.
Carbon and mild steels
- Suitable wire diameter:
- Welding current range:
- Arc voltage range:
- Suitable gases:
Stainless steels
- Suitable wire diameter:
- Welding current range:
- Arc voltage range:
- Suitable gases:
Aluminium and alloys
- Suitable wire diameter:
- Welding current range:
- Arc voltage range:
Air pressure Flow rate
Max. bar
150 4.0
250 4.0
400 4.0
450 5.5
600 5.5
0.6-1.2mm
CO , mix Ar/CO , Ar/CO
2 2
mix Ar/O , Ar/CO
2
0.8-1.6mm
- Suitable gases:
Generally, the contact tip should be flush with the nozzle or protrude slightly when
using the thinnest wires and lowest arc voltages; the length of free wire (stick-out) will
normally be between 5 and 12mm.
Application: Welding in all positions, on thin material or for the first passage in
bevelled edges, with the advantage of limited heat transfer and highly controllable
pool.
Note: SHORT ARC transfer for welding aluminium and alloys should be used with
great care (especially with wires of diameter >1mm) because the risk of melting
defects may arise.
6.4.2 SPRAY ARC TRANSFER MODE
Higher voltages and currents than for "short arc" are used here to achieve the melting
of the wire. The wire tip does not come into contact with the molten pool; an arc forms
from the tip and through it flows a stream of metallic droplets. These are produeced by
the continuous melting of the electrode wire without short-circuits involved.
Carbon and mild steels
- Suitable wire diameter:
- Welding current range:
- Arc voltage range:
- Suitable gases:
Stainless steels
- Suitable wire diameter:
- Welding current range:
- Welding voltage range:
- Suitable gases:
Aluminium and alloys
- Suitable wire diameter:
- Welding current range:
- welding voltage range:
- suitable gases:
The contact tip should generally be 5-10mm inside the nozzle, the higher the arc
voltage the further inside; the length of free wire (stick-out) should normally be
between 10 and 12mm.
Application: Horizontal welding with thicknesses of at least 3-4mm (very fluid pool);
execution rate and deposit rate are very high (high heat transfer).
6.4.3 Adjusting the MIG-MAG welding parameters
6.4.3.1 Protective gas
The protective gas flow rate must be set according to the intensity of the welding
current and the nozzle diameter:
short arc: 8-14 l/min;
spray arc: 12-20 l/min
6.4.3.2 Welding voltage and wire speed
The welding voltage is set by the operator by rotating the encoder knob (FIG. D
(8)), while the wire speed is set directly on the front panel of the feeder. The welding
current cannot be set directly, but is obtained according to the voltage and wire speed
settings. Use the push-button (FIG. D (9)) to see the output current on the display (10).
The output voltage is tied to the output current as follows:
V = ( 14+0.05 I ) where:
2 2
- V = Output voltage in volts.
2
- I = Output current in amperes.
2
Approximate values of current for the most commonly used wires are given in Table 4.
7. MAINTENANCE
WARNING! BEFORE CARRYING OUT MAINTENANCE OPERATIONS
MAKE SURE THE WELDING MACHINE IS SWITCHED OFF AND DISCONNECTED
FROM THE MAIN POWER SUPPLY.
7.1 ROUTINE MAINTENANCE
ROUTINE MAINTENANCE OPERATIONS CAN BE CARRIED OUT BY THE
OPERATOR.
7.1.1 Torch
- Do not put the torch or its cable on hot pieces; this would cause the insulating
materials to melt, making the torch unusable after a very short time.
- Make regular checks on the gas pipe and connector seals.
- Accurately match collet and collet body with the selected electrode diameter in order
to avoid overheating, bad gas diffusion and poor performance.
- At least once a day check the terminal parts of the torch for wear and make sure they
are assembled correctly: nozzle, electrode, electrode-holder clamp, gas diffuser.
7.2 EXTRAORDINARY MAINTENANCE
EXTRAORDINARY MAINTENANCE MUST ONLY BE CARRIED OUT BY
m /h
3
TECHNICIANS WHO ARE EXPERT OR QUALIFIED IN THE ELECTRIC-
15
MECHANICAL FIELD, AND IN FULL RESPECT OF THE IEC/EN 60974-4
TECHNICAL DIRECTIVE.
15
15
WARNING! BEFORE REMOVING THE WELDING MACHINE PANELS
40
AND WORKING INSIDE THE MACHINE MAKE SURE THE WELDING MACHINE
IS SWITCHED OFF AND DISCONNECTED FROM THE MAIN POWER SUPPLY
40
OUTLET.
If checks are made inside the welding machine while it is live, this may cause
serious electric shock due to direct contact with live parts and/or injury due to
direct contact with moving parts.
- Periodically, and in any case with a frequency in keeping with the utilisation and with
the environment's dust conditions, inspect the inside of the welding machine and
remove the dust deposited on the electronic boards with a very soft brush or with
appropriate solvents.
40-210A
- At the same time make sure the electrical connections are tight and check the wiring
14-23V
for damage to the insulation.
/O
2 2
- At the end of these operations re-assemble the panels of the welding machine and
screw the fastening screws right down.
0.8-1mm
- Never, ever carry out welding operations while the welding machine is open.
40-160A
- After having carried out maintenance or repairs, restore the connections and wiring
14-20V
as they were before, making sure they do not come into contact with moving parts or
(1-2%)
2
parts that can reach high temperatures. Tie all the wires as they were before, being
careful to keep the high voltage connections of the primary transformer separate
from the low voltage ones of the secondary transformer.
75-160A
Use all the original washers and screws when closing the casing.
16-22V
- 8 -
Ar 99.9%
0.8-1.6mm
180-450A
24-40V
mix Ar/CO , Ar/CO /O
2 2 2
1-1.6mm
140-390A
22-32V
mix Ar/O , Ar/CO (1-2%)
2 2
0.8-1.6mm
120-360A
24-30V
Ar 99.9%