FRO­NIUS MTG 320i US Style User manual

Fronius prints on elemental chlorine free paper (ECF) sourced from certified sustainable forests (FSC).
/ Perfect Charging / Perfect Welding / Solar Energy
42,0410,2329 005-02062020
MTG 320i US Style
MTG 400i US Style
MTG 270i US Style
MTG 320i US-Style
MTG 400i US-Style
MTG 270i US-Style
[
Operating Instructions
MIG/MAG manual welding torch
Manual de instrucciones
Antorcha manual MIG/MAG
Instructions de service
Torche de soudage MIG/MAG ma-
nuelle
ENESFR

2

3
EN
Contents
Safety......................................................................................................................................................... 5
Proper use ............................................................................................................................................ 5
Safety.................................................................................................................................................... 5
General ...................................................................................................................................................... 6
General ................................................................................................................................................. 6
Available versions................................................................................................................................. 6
Available central connectors................................................................................................................. 7
Installation and commissioning .................................................................................................................. 8
Fitting wearing parts to the torch body.................................................................................................. 8
FSC: Fitting the inner liner inside the torch hosepack .......................................................................... 9
OC (Euro, Miller, SKS): Fitting the inner liner inside the torch hosepack ............................................ 10
OC (Lincoln, Hobart): Fitting the inner liner inside the torch hosepack ................................................ 11
Connecting the welding torch to the wirefeeder.................................................................................... 12
Connecting the welding torch to the power source............................................................................... 12
Care, maintenance and disposal ............................................................................................................... 14
General ................................................................................................................................................. 14
Recognising faulty wearing parts.......................................................................................................... 14
Maintenance at every start-up .............................................................................................................. 14
Maintenance every time the wirespool/basket-type spool is changed.................................................. 15
Troubleshooting ......................................................................................................................................... 16
Troubleshooting .................................................................................................................................... 16
Technical data............................................................................................................................................ 21
General ................................................................................................................................................. 21
MTG 320i / 400i US Style ..................................................................................................................... 21
MTG 270i US Style machine welding torch .......................................................................................... 21

4

5
EN
Safety
Proper use The MIG/MAG manual welding torch is intended solely for MIG/MAG welding in manual ap-
plications.
Any use above and beyond this purpose is deemed improper. The manufacturer shall not
be held liable for any damage arising from such usage.
Proper use includes:
- Carefully reading and following all the instructions given in the operating instructions
- Performing all stipulated inspection and maintenance work.
Safety WARNING!
Incorrect operation or poorly executed work can cause serious injury or damage.
► All activities described in these Operating Instructions may only be carried out by
trained and qualified personnel.
► All functions described in these Operating Instructions may only be used by trained and
qualified personnel.
► Do not carry out any of the work or use any of the functions described until you have
fully read and understood the following documents:
these Operating Instructions,
the enclosed "Safety rules" document,
all the Operating Instructions for the system components, especially the safety rules.
WARNING!
An electric shock can be fatal.
There is also a risk of injury from the emerging wire electrode. Before commencing any of
the work described in these Operating Instructions:
► Turn the power source mains switch to the "O" position
► Disconnect the power source from the mains
► Ensure that the power source remains disconnected from the mains until all work has
been completed
CAUTION!
Welding torch components that have become very hot during use can cause severe
burns.
► Before commencing any of the work described in these Operating Instructions, allow
all welding torch components to cool to room temperature (+25 °C, +77 °F).
CAUTION!
Risk of injury and damage from loose connections.
► All cables, lines and hosepacks must be properly connected, undamaged, correctly in-
sulated and adequately dimensioned at all times.

6
General
General MIG/MAG welding torches are particularly robust and reliable, with an ergonomic grip, ball
joint and perfect weight distribution for fatigue-free working. The welding torches are avail-
able as gas-cooled and water-cooled versions in different power categories and sizes, so
no weld seam is out of reach. The welding torches can be used in an extremely wide range
of applications. They are ideal for manual batch and single-piece production as well as jobs
in the workshop.
Available ver-
sions
The MIG/MAG welding torch is available in three versions:
EH - with ergonomic handle SH - with straight handle
M - as a machine welding torch

7
EN
Available central
connectors
The MIG/MAG welding torch is available with two different central connectors:
FSC - Fronius System Connector
OC - Open connectors
suitable for:
- Euro
- Lincoln
- Miller
- Hobart
- SKS
- etc.
PowerPin OC

8
Installation and commissioning
Fitting wearing
parts to the torch
body
1 2
3
** Screw on and tighten the gas nozzle as far as it will go
1
2
3

9
EN
FSC: Fitting the
inner liner inside
the torch hose-
pack
NOTE!
Ensure that the hosepack is straight when fitting the inner liner, otherwise the liner
might not be inserted correctly.
1 2
3 4
5 6
**** Screw the cap onto the inner liner as far as it will go. The inner liner must be visible
through the hole in the cap.
1
1
2
2
3
4
5
6

10
OC (Euro, Miller,
SKS): Fitting the
inner liner inside
the torch hose-
pack
NOTE!
Ensure that the hosepack is straight when fitting the inner liner, otherwise the liner
might not be inserted correctly.
1 2
3 4
5 6
1
1
2
2
3
4
5
2
6

11
EN
OC (Lincoln, Ho-
bart): Fitting the
inner liner inside
the torch hose-
pack
NOTE!
Ensure that the hosepack is straight when fitting the inner liner, otherwise the liner
might not be inserted correctly.
1 2
3 4
5 6
1
1
2
2
3
4
5
2
3
6

12
7
Connecting the
welding torch to
the wirefeeder
1
Connecting the
welding torch to
the power source
1 2
2
3
7
1
1
2

13
EN
1
3

14
Care, maintenance and disposal
General Regular preventive maintenance of the welding torch is essential if trouble-free operation
is to be ensured. The welding torch is subjected to high temperatures and heavy soiling.
The welding torch therefore requires more frequent maintenance than other components
in the welding system.
NOTE!
When removing welding spatter, avoid
scoring or scratching the torch.
Future welding spatter may become firmly
lodged in score or scratch marks.
Do not bend the torch body under any cir-
cumstances!
Recognising
faulty wearing
parts
1. Insulating parts
– Burned-off outside edges, notches
2. Nozzle fittings
– Burned-off outside edges, notches
– Heavily covered in welding spatter
3. Spatter guard
– Burned-off outside edges, notches
4. Contact tips
– Worn-out (oval) wire entry and wire exit holes
– Heavily covered in welding spatter
– Fusion penetration on the tip of the contact tube
5. Gas nozzles
– Heavily covered in welding spatter
– Burned-off outside edges
– Notches
Maintenance at
every start-up
- Check wearing parts
- replace faulty wearing parts
- Remove welding spatter from gas nozzle
1. 2. 3. 4. 5.

15
EN
1 2
* Check the gas nozzle, spatter guard and insulation for damage and replace any
damaged components.
Maintenance
every time the
wirespool/basket-
type spool is
changed
- Clean wirefeeding hose with reduced compressed air
- Recommended: replace the inner liner. Clean the wearing parts before fitting the new
inner liner
1 2
1
2
1
2

16
Troubleshooting
Troubleshooting No welding current
Power source mains switch is on, indicators on the power source are lit up, shielding gas
available
Cause: Grounding (earthing) connection is incorrect
Remedy: Establish a proper grounding (earthing) connection
Cause: There is a break in the current cable in the welding torch
Remedy: Replace welding torch
Nothing happens when the torch trigger is pressed
Power source mains switch is on, indicators on the power source are lit up
Cause: The FSC ('Fronius System Connector' central connector) is not plugged in
properly
Remedy: Push on the FSC as far as it will go
Cause: Welding torch or welding torch control line is faulty
Remedy: Replace welding torch
Cause: Interconnecting hosepack faulty or not connected properly
Remedy: Connect interconnecting hosepack properly
Replace faulty interconnecting hosepack
Cause: Faulty power source
Remedy: Contact After-Sales Service
No shielding gas
All other functions are OK
Cause: Gas cylinder is empty
Remedy: Change the gas cylinder
Cause: Gas pressure regulator is faulty
Remedy: Replace gas pressure regulator
Cause: The gas hose is not connected, or is damaged or kinked
Remedy: Fit gas hose, lay out straight Replace faulty gas hose
Cause: Welding torch is faulty
Remedy: Replace welding torch
Cause: Gas solenoid valve is faulty
Remedy: Contact After-Sales Service (arrange for gas solenoid valve to be replaced)

17
EN
Poor weld properties
Cause: Incorrect welding parameters
Remedy: Correct settings
Cause: Poor grounding (earthing) connection
Remedy: Ensure good contact to workpiece
Cause: Inadequate or no protective gas shield
Remedy: Check the pressure regulator, gas hose, gas solenoid valve and welding torch
shielding gas connection. On gas-cooled welding torches, inspect the gas
seals, use a suitable inner liner
Cause: Contact tip is too large or worn out
Remedy: Replace the contact tip
Cause: Wrong wire alloy or wrong wire diameter
Remedy: Check wirespool/basket-type spool in use
Cause: Wrong wire alloy or wrong wire diameter
Remedy: Check weldability of the base material
Cause: The shielding gas is not suitable for this wire alloy
Remedy: Use the correct shielding gas
Cause: Unfavourable welding conditions: shielding gas is contaminated (by moisture,
air), inadequate gas shield (weld pool "boiling", draughts), contaminants in
the workpiece (rust, paint, grease)
Remedy: Optimise the welding conditions
Cause: Welding spatter in the gas nozzle
Remedy: Remove welding spatter
Cause: Turbulence caused by too high a rate of shielding gas flow
Remedy: Reduce shielding gas flow rate, recommended:
shielding gas flow rate (l/min) = wire diameter (mm) x 10
(e.g. 16 l/min for 1.6 mm wire electrode)
Cause: Too large a distance between the welding torch and the workpiece
Remedy: Reduce the distance between the welding torch and the workpiece (approx.
10 - 15 mm / 0.39 - 0.59 in.)
Cause: Tilt angle of the welding torch is too great
Remedy: Reduce the tilt angle of the welding torch
Cause: Wirefeed components do not match the diameter of the wire electrode / the
wire electrode material
Remedy: Use the correct wirefeed components

18
Poor wirefeed
Cause: Depending on the system, brake force in wire-feed unit or power source set
too high
Remedy: Reduce the braking force
Cause: Hole in the contact tip is displaced
Remedy: Replace the contact tip
Cause: The inner liner or wire-guide insert is defective
Remedy: Check the inner liner and wire-guide insert for kinks, dirt, etc.
Change the faulty inner liner or wire-guide insert
Cause: The wirefeeder rollers are not suitable for the wire electrode being used
Remedy: Use suitable wirefeeder rollers
Cause: Wirefeeder rollers have the wrong contact pressure
Remedy: Optimise the contact pressure
Cause: The wirefeeder rollers are soiled or damaged
Remedy: Clean the wirefeeder rollers or replace them by new ones
Cause: Inner liner wrongly laid or kinked
Remedy: Replace inner liner
Cause: The inner liner has been cut too short
Remedy: Replace the inner liner and cut the new inner liner to the correct length
Cause: Wire electrode worn due to excessive contact pressure on the wirefeeder roll-
ers
Remedy: Reduce contact pressure on the wirefeeder rollers
Cause: Wire electrode contains impurities or is corroded
Remedy: Use high-quality wire electrode with no impurities
Cause: For steel inner liners: use of uncoated inner liner
Remedy: Use a coated inner liner
The gas nozzle becomes very hot
Cause: No thermal dissipation as the gas nozzle is too loose
Remedy: Screw on the gas nozzle as far as it will go
Welding torch becomes very hot
Cause: Welding torch operated above the maximum welding current
Remedy: Reduce welding power or use a more powerful welding torch
Cause: Welding torch is inadequately dimensioned
Remedy: Observe the duty cycle and loading limits
Cause: The tip of the welding torch is too close to the arc
Remedy: Increase stick out

19
EN
Contact tip has a short service life
Cause: Incorrect wirefeeder rollers
Remedy: Use correct wirefeeder rollers
Cause: Wire electrode worn due to excessive contact pressure on the wirefeeder roll-
ers
Remedy: Reduce contact pressure on the wirefeeder rollers
Cause: Wire electrode contains impurities/is corroded
Remedy: Use high-quality wire electrode with no impurities
Cause: Uncoated wire electrode
Remedy: Use wire electrode with suitable coating
Cause: Wrong dimension of contact tip
Remedy: Use a contact tip of the correct dimension
Cause: Duty cycle of welding torch has been exceeded
Remedy: Shorten the duty cycle or use a more powerful welding torch
Cause: Contact tip has overheated. No thermal dissipation as the contact tip is too
loose
Remedy: Tighten the contact tip
NOTE!
When using CrNi, the contact tip may be subject to a higher degree of wear due to
the nature of the surface of the CrNi wire electrode.
Torch trigger malfunction
Cause: Defective plug connection between welding torch and power source
Remedy: Establish proper plug connections / have power source or welding torch ser-
viced
Cause: Build up of dirt between torch trigger and torch trigger housing
Remedy: Clean away the dirt
Cause: Control line is faulty
Remedy: Contact After-Sales Service

20
Weld seam porosity
Cause: Spatter build-up in the gas nozzle causing inadequate gas shield for weld
seam
Remedy: Remove welding spatter
Cause: Holes in gas hose or hose is not connected properly
Remedy: Replace gas hose
Cause: O-ring on central connector has been cut or is faulty
Remedy: Replace O-ring
Cause: Moisture/condensation in the gas line
Remedy: Dry gas line
Cause: Gas flow is either too high or too low
Remedy: Correct gas flow
Cause: Insufficient gas flow at start or end of welding
Remedy: Increase gas pre-flow and gas post-flow
Cause: Rusty or poor quality wire electrode
Remedy: Use high-quality wire electrode with no impurities
Cause: For gas-cooled welding torches: gas is escaping through a non-insulated in-
ner liner
Remedy: Use only insulated inner liners with gas-cooled welding torches
Cause: Too much parting agent applied
Remedy: Remove excess parting agent/apply less parting agent