Page 204 - CITS - Welder - Trade Practical

WELDER - CITS

• Wear chipping goggle for the protection of eyes.
• Deposit the final covering run with a weave motion with150-160amps welding current.
Note: Prevent the upper edge of the plate from melting off.

• Remove the slag from the final weld and clean thoroughly.

Note: Use a weld gauge to check the fillet size.
• Inspect the lap fillet weld for surface defects and size.

Skill Sequence

Construct & evaluate single v butt joint on m.s. plate (10 mm. thick
plate) in flat position by GMAW

Objectives: At the end of this exercise you shall be able to
• Construct & evaluate single v butt joint on m.s. plate (10 mm. thick plate) in flat position by GMAW.

Setting and tacking the lap joint (Fig 1)
Set the joint with an overlap of 2.5mm.
The overlap may vary based on the plate thickness.
Tack-weld on both ends. (Fig 1) Ensure the 2 lapping sur-faces are perfectly cleaned and they contact each other
properly. Use 120-amp current for tacking.
Set the joint in a flat position using angle iron (Fig 2).
Welding the lap fillet joint in flat position
Deposit root run with 100-110 amp curre
Maintain 80° angle to the line of the weld and 45° between the weld faces. (Fig 2)
Maintain a short arc to get uniform fusion and root penetration.
Note: Avoid side-to-side movement of the electrode.

Deslag and clean the root bead thoroughly.
Deposit the final covering run with a 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 lap fillet weld and ensure.
Fig 1 Fig 2

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CITS : C G & M - Welder - Exercise 51 CITS : C G & M - Welder - Exercise 51