Page 214 - CITS - Welder - Trade Practical

WELDER - CITS

Skill Sequence

Construct corner joint on M.S. plate (3 mm. thick plate) in horizontal

position by GMAW

Objectives: At the end of this exercise you shall be able to
• construct corner joint on m.s. plate (3 mm. thick plate) in horizontal position by GMAW.

1 Cut the sheet by shearing machine as per drawing.

2 Grind and file the edges of sheet to square.
3 Deburr and clean the surface of the plates by carbon steel wire brush and filing.
4 Set the plate in the form of Corner joint at 90degrees with specified root gap in flat position as per drawing.
5 Wear protective clothing.
6 Connect the torch to positive terminal of the machine.

7 Set current to 90 - 100 amperes/corresponding wire feeding rate 19 to 20 arc voltage and deposit the root.
8 Run using dip transfer mode.
9 Tack weld (min 10 mm length) on both ends of the corner joint.
10 Keep the tack welded job in horizontal position.

11 Weld the corner joint by using 0.8 mm dia. mild steel filler wire and using stringer bead welding technique.
12 Deposit root run on the joint by forming key hole and obtain complete penetration and even fusion of plates.
Note: Avoid side-to-side movement of the electrode.

Deslag and clean the root bead thoroughly.
Deposit the final covering run with 160 amp current.
Give side-to-side movement to the electrode not more than 2.5 times its dia.

Use the same electrode angle as was used for the root bead.
Note: Prevent the upper edge of the plate from melting off by not allowing the arc to concentrate
more on the upper edge.
Remove the slag with a chipping hammer.
Clean the weld with a steel wire brush.
Inspect the fillet corner weld and ensure.

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CITS : C G & M - Welder - Exercise 52(C)