Lincoln Electric IM702-A manual Making a TIG Weld with AN Amptrol

B-12 OPERATION B-12

MAKING A TIG WELD WITH AN AMPTROL

1.Install welding equipment per Section A-5.

2.Setup controls per Section B-10.

3.Turn on the shielding gas supply, and torch coolant

input supply (if used).

Note: The Precision TIG Under-Cooler (or Water Solenoid connected to the Cooler receptacle) runs with the Fan-As-Needed machine cooling fan (See Maintenance Section D), so the cooler fan and water pump will also not run continuously in idle, but will run while welding.

4.With the torch held safely away from everything, close the Arc Start Switch of the Amptrol and set the gas flow meter. Then open the switch. The welder is now ready for welding.

5.Position the tungsten electrode at the start of the weld at a 65° to 75° angle with the horizontal, in the direction of pushing travel, so that the electrode is approximately 1/8" (4 mm) above the work piece.

Close the arc start switch. This opens the gas valve to automatically purge air from the hose and torch, then shields the arc strike area. After the 0.5 sec- ond preflow time, the high frequency becomes available to strike the arc. When the arc strikes the torch coolant (if used) starts to flow. Also, if welding DC- TIG, the high frequency shuts off just after the arc strikes.

6.Hold the arc start switch closed at minimum Amptrol Start level (See Section B-10) until an arc is estab- lished, then increase the output to the desired weld- ing level and push the torch in the direction of trav- el.

7.At the end of the weld, decrease the Amptrol output to the crater-fill level before releasing the arc start switch to start the Postflow time. Hold the torch gas shielding over the solidifying weld crater while post- flow time expires and the gas valve reopens. The torch coolant (if used) continues to flow for up to 8 minutes after the arc goes out (with the Fan-As- Needed feature) to assure torch cooling.

•Repeat steps 5 through 7 to make another weld.

RECOMMENDED ELECTRODE AMPERAGE RANGES - PRECISION TIG 275

SMAW Process

ELECTRODE

POLARITY

3/32"

1/8"

5/32"

Fleetweld 5P, Fleetweld 5P+

DC+

40 - 70

75 - 130

90 - 175

Fleetweld 180

DC+

40 - 80

55 - 110

105 - 135

Fleetweld 37

DC+

70 - 95

100 - 135

145 - 180

Fleetweld 47

DC-

75 - 95

100 - 145

135 - 200

Jet-LH MR

DC+

85 - 110

110 - 160

130 - 220

Blue Max Stainless

DC+

40 - 80

75 - 110

95 - 110

Red Baron Stainless

DC+

40 - 70

60 - 100

90 - 140

Mild steel procedures are based on recommended procedures listed in C2.10 8/94 and the maximum rating of the PRECISION TIG 275

Excaliber 7018 procedures are based on Jet-LH 78 MR

Blue Max procedures are based on C6.1 6/95

Red Baron Procedure are based on ES-503 10/93

GTAW Process

Electrode Polarity

DC-

AC*

Approximate Argon

Electrode Tip Preparation

Sharpened

Balled

Gas Flow Rate

Electrode Type

EWZr

C.F.H. (l/min.)

EWTh-1, EWCe-2

EWTh-1, EWTh-2

EWTh-2, EWLa-1

EWP

EWCe-2, EWLa-1

Stainless

Electrode Size (in.)

EWG

EWG

Aluminum

Steel

.010

Up to 15 A.

Up to 15 A.

Up to 15 A.

3-8

(2-4)

3-8

(2-4)

.020

Up to 15 A.

10 to 15 A.

5 to 20 A.

5-10

(3-5)

5-10

(3-5)

.040

Up to 80 A.

20 to 30 A.

20 to 60 A.

5-10

(3-5)

5-10

(3-5)

1/16

Up to 150 A.

30 to 80 A.

60 to 120 A.

5-10

(3-5)

9-13 (4-6)

3/32

Up to MAX. A.

60 to 130 A.

100 to 180 A.

13-17 (6-8)

11-15 (5-7)

1/8

X

100 to 180 A.

160 to 250 A.

15-23

(7-11)

11-15

(5-7)

Tungsten electrodes are classified as follows by the American Welding Society (AWS):

Pure

EWP

green

+1% Thoria

EWTh-1

yellow

+2% Thoria

EWTh-2

red

+2% Ceria

EWCe-2

.....orange

+1.5% Lanthana

EWLa-1

black

+0.15 to 0.40% Zirconia

EWZr

brown

Ceriated Tungsten is now widely accepted as a substitute for 2% Thoriated Tungsten in AC and DC applications.

*Balanced Wave, Unbalanced Wave requires derating of the electrode.

PRECISION TIG 275