Page 43 - CITS - Welder - Trade Practical

WELDER - CITS

Job Sequence

• Clean and inspect the lap fillet weld for surface defects.
• Cut the plate pieces by gas cutting as per drawing.
• Grind the gas-cut edges to square.
• Remove the grinding burrs and clean the surfaces by Wire brush.
• Set the pieces in the form of a lap joint as per drawing.

• Select DCEN polarity, in case of a DC machine.
Note: Wear protective clothing.
• Tack-weld on both ends.
• Set the lap joint in a flat position.
• Deposit root run by using a 3.15mm dia. Medium coated M.S. electrode with 100-110 amps current.
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 a 4.00 mm dia. Medium coated M.S. electrode with
150-160 amps 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.
• Inspect the lap fillet weld for surface defects and size.

Skill Sequence

Lap fillet joint in flat position

Objectives: At the end of this exercise you shall be able to
• prepare and weld lap fillet joint in flat position.

Setting and tacking the lap joint (Fig 1)
Set the lap joint with an overlap of 25mm.

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 a 3.15mmø MS electrode with 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 a 3.15mmø medium coated MS electrode with 100-110 amp current.
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.

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CITS : C G & M - Welder - Exercise 6