Page 187 - CITS - Fitter Trade Pactical - Volume - 2

FITTER - CITS

TABLE 1
Guideline for Manual AC GTA welding of aluminium

Plate Welding Joint type Current AC Electrode Nozzle Argon Filler Number
thickness position (Amp) Dia.(mm) size flow rod of
(mm) (10) mm Rate Dia. runs
(mm) LPM mm

2 mm F Square butt 70 - 100 2.4 8.0 10 2.4 1
H, V Square butt 70 - 100 2.4 8.0 10 2.4 1
O Square butt 60 - 90 2.4 8.0 13 2.4 1
3.2 F Square butt 120 - 150 3.2 9.5 10 3.2 1
H, V Square butt 110 - 140 3.2 9.5 10 3.2 1
O Square butt 110 - 140 3.2 9.5 13 3.2 1
4.8 F 60 Single Vee 180 - 220 4.0 11 12 4.0 2
0
H, V 60 Single Vee 160 - 200 4.0 11 12 4.0 2
0
O 60 Single Vee 170 - 200 4.0 11 12 4.0 2
0
6.35 F 60 Single Vee 220 - 240 4.8 12.7 15 4.0 2
0
H, V 60 Single Vee 220 - 240 4.8 12.7 15 4.0 2
0
O 60 Single Vee 210 - 250 4.8 12.7 18 4.0 2
0
F - Flat, H - Horizontal, V - Vertical, O - Overhead
Maintain uniform short arc throughtout the welding.
Care to be taken to avoid end crater.
During welding a temporary backing is to be given on the underside to support the penetration bead.

Fig 2

Fillet weld - Tee joint on aluminium sheet 2mm - position

flat (1F)

Objectives : At the end of this exercise you shall be able to
• weld a Tee fillet joint using 5% Silicon Aluminium Filler wire in flat position by TIG welding process.
Job Sequence

1 Prepare aluminium sheets as per dimensions.
2 Clean the edges of the sheets by the chemical cleaning method and deburr. Use the stainless steel wire brush
for surface cleaning.

3 Set the “Tee” joint for aluminium welding.
4 Use 2.4mm size tungsten (zirconium) electrode.
5 Select 95% aluminium 5% silicon filler wire 1.6mmf.
6 Weld Tee joint in flat position using leftward technique.
7 Clean the weld area thoroughly.

8 Inspect the job.

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CITS : C G & M - Fitter - Exercise 52