Page 180 - CITS - Fitter Trade Pactical - Volume - 2

FITTER - CITS

Skill Sequence

Square butt joint by arc in flat position (TASK 1)

Objectives: At the end of this exercise you shall be able to
• weld a square butt joint in a flat position
• inspect the completed butt weld.

This type of joint is used very extensively in industry. If welded from both the sides (6 mm plate thickness), a
sound weld can be obtained.
Setting and tacking

Set the pieces as butt joints with a 3 mm gap in a welding.
Tack at both the ends and one in the centre. (Fig 1)

Fig 1

Use a Ø 3.15mm M.S electrode. Set the current

120-130 amps and length of the tack 15 mm.
Ensure the tacks are fused.
Check the alignment after tacking, and reset, if necessary (Fig 2).

Fig 2

Check the tack-welds thoroughly.
Welding butt joint
Place the joint in a flat position.

Deposit the first bead, using a Æ4mm M.S. electrode and 150-160 amps current with a correct:
• Electrode angle
• Travel speed, and
• Arc length. (Fig 3)

165

CITS : C G & M - Fitter - Exercise 51