Tig Welding; Typical Current Ranges For Tungsten Electrodes - Lincoln Electric DUAL VANTAGE 700 (AU) Operator's Manual

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DUAL VANTAGE
®
700 (AU)

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 current 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 tung-
sten contamination. Then, the tungsten is gently lifted off
the work in a rocking motion, which establishes the arc.
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 DUAL VANTAGE
700 (AU) an be used in a wide
®
variety of DC TIG welding applications. In general the
'Touch Start' feature allows contamination free start-
ing without the use of a Hi-frequency unit.
TYPICAL CURRENT RANGES
Tungsten Electrode
DCEN (-)
Diameter in. (mm)
1%, 2% Thoriated
Tungsten
.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 = 1/2 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.
TABLE B.3
FOR TUNGSTEN ELECTRODES
(1)
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
B-8
If desired, the K930-2 TIG Module can be used with
the DUAL VANTAGE
700 (AU). The settings are for
®
reference.
DUAL VANTAGE
700 (AU) 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.
• Set the "WELDING TERMINALS" switch to the
"REMOTELY CONTROLLED" position.
This will keep the "Solid State" contactor open and
provide a "cold" electrode until the Amptrol or Arc
Start Switch is pressed.
When using the TIG Module, the OUTPUT CONTROL
on the DUAL VANTAGE
maximum range of the CURRENT CONTROL on the
TIG Module or an Amptrol if connected to the TIG
Module.
NOTE: The TIG process is to receive a low voltage
welding process. There is no difference in
operation with the VRD "On" or "Off" for this
mode. For indicator light operation, see Table
B.1.
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)
OPERATION
700 (AU) is used to set the
®
(2)
TIG TORCH
Nozzle Size (4), (5)

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