Tig Welding; Typical Current Ranges For Tungsten Electrodes - Lincoln Electric VANTAGE 400 Service Manual

B-7
The OUTPUT CONTROL dial adjusts the full output range
for pipe welding.
The ARC CONTROL dial sets the short circuit current
(arc-force) during stick welding to adjust for a soft or more
forceful digging arc (crisp). Increasing the number from -
10(soft) to +10(crisp) increases the short circuit current
which results in a more forceful digging arc.
Typically a forceful digging arc is preferred for root and hot
passes. A softer arc is preferred for fill and cap passes
where weld puddle control and deposition ("stacking" of
iron) are key to fast travel speeds. This can also increase
spatter.
It is recommended that the ARC CONTROL be set to the
minimum number without electrode sticking. Start with the
dial set at 0.
NOTE: With the VRD switch in the "ON" position there is
no output in the DOWNHILL PIPE mode. For indicator
light operation, see Table B.1.

TIG WELDING

The TOUCH START TIG setting of the MODE switch is for
DC TIG (Tungsten Inert Gas) welding. To initiate a weld,
the OUTPUT CONTROL dial is first set to the desired cur-
rent and the tungsten is touched to the work. During the
time the tungsten is touching the work there is very little
voltage or current and, in general, no tungsten contami-
nation. Then, the tungsten is gently lifted off the work in a
rocking motion, which establishes the arc.
TYPICAL CURRENT RANGES
Tungsten Electrode DCEN (-)
Diameter in. (mm)
1%, 2% Thoriated
Tungsten
0.010 (.25) 2-15
0.020 (.50) 5-20
0.040 (1.0) 15-80
1/16 (1.6) 70-150
3/32 (2.4) 150-250
1/8 (3.2) 250-400
5/32 (4.0) 400-500
3/16 (4.8) 500-750
1/4 (6.4) 750-1000
(1) When used with argon gas. The current ranges shown must be reduced when using argon/helium or pure helium shielding gases.
(2) Tungsten electrodes are classified as follows by the American Welding Society (AWS):
Pure
1% Thoriated
2% Thoriated
Though not yet recognized by the AWS, Ceriated Tungsten is now widely accepted as a substitute for 2% Thoriated Tungsten in AC and DC applications.
(3) DCEP is not commonly used in these sizes.
(4) TIG torch nozzle "sizes" are in multiples of 1/16ths of an inch:
# 4 = 1/4 in. (6 mm)
# 5 = 5/16 in. (8 mm)
# 6 = 3/8 in. (10 mm)
# 7 = 7/16 in. (11 mm)
# 8 = _ in. (12.5 mm)
#10 = 5/8 in. (16 mm)
(5) TIG torch nozzles are typically made from alumina ceramic. Special applications may require lava nozzles, which are less prone to breakage, but cannot withstand high temperatures
and high duty cycles.
THEORY OF OPERATION
TABLE B.3
(1)
FOR TUNGSTEN ELECTRODES
DCEP (+) Approximate Argon Gas Flow
Flow Rate C.F.H. ( l /min.)
1%, 2% Thoriated Aluminum
Tungsten
(3) 3-8 (2-4)
(3) 5-10 (3-5)
(3) 5-10 (3-5)
10-20 5-10 (3-5)
15-30 13-17 (6-8)
25-40 15-23 (7-11)
40-55 21-25 (10-12)
55-80 23-27 (11-13)
80-125 28-32 (13-15)
EWP
EWTh-1
EWTh-2
VANTAGE® 400
When in the TOUCH START TIG mode and when a
Amptrol is connected to the 6-Pin connector the OUT-
PUT CONTROL dial is used to set the maximum cur-
rent range of the current control of the Amptrol.
The ARC CONTROL is not active in the TIG mode. To
STOP a weld, simply pull the TIG torch away from the
work.
When the arc voltage reaches approximately 30 Volts
the arc will go out and the machine will reset the cur-
rent to the Touch Start level.
To reinitiate the arc, retouch the tungsten to the work
and lift. Alternatively, the weld can be stopped by
releasing the Amptrol or arc start switch.
The VANTAGE® 400 can be used in a wide variety of
DC TIG welding applications. In general the 'Touch
Start' feature allows contamination free starting without
the use of a Hi-frequency unit. If desired, the K930-2
TIG Module can be used with the VANTAGE® 400.
The settings are for reference.
VANTAGE® 400 settings when using the K930-2 TIG
Module with an Amptrol or Arc Start Switch:
• Set the MODE Switch to the TOUCH START TIG
setting.
• Set the "IDLER" Switch to the "AUTO" position.
Nozzle Size (4), (5)
Stainless Steel
3-8 (2-4) #4, #5, #6
5-10 (3-5)
5-10 (3-5)
9-13 (4-6) #5, #6
11-15 (5-7) #6, #7, #8
11-15 (5-7)
13-17 (6-8) #8, #10
18-22 (8-10)
23-27 (11-13)
B-7
(2)
TIG TORCH