Page 78 - CITS - Welder - Trade Practical

WELDER - CITS

Job Sequence

• Mark the plate and cut to given size.
• Prepare the square edges.
• Set the lap joint without gap and tack the plate on both Ends.

• Clamp the job for overhead lap welding.
• Select 3.15ø electrode and set the current.
• Hold the electrode at an angle of 45° to the plate sur- face and an angle of 15° to the perpendicular to the line
of weld.
• Lay the first bead at the root without weaving the electrode.
• Clean the slag using a chipping hammer.
• Deposit 2nd and 3rd run using stringer beads.

• Deslag, clean and inspect the joint
Skill Sequence

Fillet lap joint on MS plate 10mm thickness in overhead

position

Objectives: At the end of this exercise you shall be able to
• prepare and weld fillet lap joint on MS plate 10mm thickness in overhead position.

Preparation and job setting

Mark and cut the plate to the given size by gas cutting.
Clean the surfaces of the plates and file to square edge.
Set lap fillet without gap and tack the plates at both ends.
Keep the lapping distance as 20mm.

Note: Wear leather gloves, hand sleeves, apron, leg guard, helmet etc.
Clamp the job for overhead welding.
Select a M.S. electrode 3.15 mm ø and set 110 amps current.
Hold the electrode so that it bisects the angle between the edge of the top plate and the surface of the bottom
plate, and is inclined slightly away from the crater, say 15°. (Fig 1)
Lay the first bead at the root of the joint with a short arc without electrode weaving.
Remove the slag from the bead using a chipping hammer and clean with a wire brush.
Use a M.S. electrode 3.15 mm ø and deposit the 2nd run with 110 amps. Current, between the 1st bead and the
surface of the plate, maintaining a short arc. The electrode angle is the same as the one mentioned for root run.
Deslag the second bead thoroughly.
Use a 3.15 mm electrode and set 110 amps current.

Deposit the 3rd bead in between the first bead and the bottom edge of the top plate (Fig 2) with a short arc and
with an electrode angle of 45° to the surface of the plate to pvoid the edge melting off the top plate.
Clean the weld thoroughly and inspect for defects, like undercut, porosity, uneven ripples and the melting off of
the edge plate.

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CITS : C G & M - Welder - Exercise 12