Lincoln Electric IM894-B manual TIG Welding, Typical Current Ranges 1 for Tungsten ELECTRODES2

Models: IM894-B

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B-6

OPERATION

B-6

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 pass- es 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 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 tungsten 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 VANTAGE® 500 (CE) can be used in a wide vari- ety of DC TIG welding applications. In general the ‘Touch Start’ feature allows contamination free start- ing without the use of a Hi-frequency unit. If desired, the K930-2 TIG Module can be used with the VAN- TAGE® 500 (CE). The settings are for reference.

VANTAGE® 500 (CE) 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.

TABLE B.3

TYPICAL CURRENT RANGES (1) FOR TUNGSTEN ELECTRODES(2)

Tungsten Electrode

DCEN (-)

DCEP (+)

Approximate Argon Gas Flow

 

TIG TORCH

 

Diameter in. (mm)

 

 

Flow Rate C.F.H. ( l

/min.)

 

Nozzle Size (4), (5)

 

 

 

 

 

 

 

 

 

 

 

 

 

1%, 2% Thoriated

1%, 2% Thoriated

Aluminum

 

 

Stainless Steel

 

 

 

 

 

Tungsten

Tungsten

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

.010

(.25)

2-15

(3)

3-8

(2-4)

 

3-8

(2-4)

#4, #5, #6

 

0.020

(.50)

5-20

(3)

5-10

(3-5)

 

5-10

(3-5)

 

 

0.040

(1.0)

15-80

(3)

5-10

(3-5)

 

5-10

(3-5)

 

 

1/16

(1.6)

70-150

10-20

5-10

(3-5)

 

9-13

(4-6)

#5, #6

 

3/32

(2.4)

150-250

15-30

13-17

(6-8)

 

11-15

(5-7)

#6, #7, #8

 

1/8

(3.2)

250-400

25-40

15-23

(7-11)

 

11-15

(5-7)

 

 

5/32

(4.0)

400-500

40-55

21-25

(10-12)

 

13-17

(6-8)

#8, #10

 

3/16

(4.8)

500-750

55-80

23-27

(11-13)

 

18-22

(8-10)

 

 

1/4

(6.4)

750-1000

80-125

28-32

(13-15)

 

23-27

(11-13)

 

 

 

 

 

 

 

 

 

 

 

 

 

(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

EWP

1% Thoriated

EWTh-1

2% Thoriated

EWTh-2

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.

VANTAGE® 500 (CE)

Page 24
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Lincoln Electric IM894-B manual TIG Welding, Typical Current Ranges 1 for Tungsten ELECTRODES2, Table B.3