Page 242 - CITS - Welder - Trade Practical

WELDER - CITS

Note: Ensure an electrode angle of 45° with the fillet corner and 80° with the welding line.
• Remove the slag with a chipping hammer and clean with a wire brush.

• Use tongs to hold the job.
• Wear chipping goggle for the protection of eyes.
• Deposit the final covering run with a weave motion using 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 butt fillet weld for surface defects and size.

Skill Sequence

Monitor square butt joint on S.S sheet. 2 mm thick by

GMAW

Objectives: At the end of this exercise you shall be able to
• monitor square butt joint on s.s sheet. 2 mm thick by GMAW.

Setting and tacking the butt joint
Set the butt joint with an overlap of 25mm.
The overlap may vary based on the plate thickness.
Tack-weld on both ends. Ensure the 2 lapping sur-faces are perfectly cleaned and they contact each other
properly current for tacking.
Set the joint in a flat position using angle iron.
Welding the butt joint in flat position

Deposit root run with a with 100-110 amp current.
Maintain 80° angle to the line of the weld and 45° between the weld faces.
Maintain a short arc to get uniform fusion and root penetration.
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 butt fillet weld and ensure:

- It has equal leg length with slight convexity
- The upper edge of the plate has not melted off
- It is free from surface defects.

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CITS : C G & M - Welder - Exercise 58(C)