Page 167 - CITS - Welder - Trade Practical

WELDER - CITS

• Arrange the 2 pipes to form as a butt joint.
• Use a fixture or V profile of an angle iron to align pipes

Wear protective clothing
• Switch ‘on’ the machine and select a 3.15 mm electrode for tacking and the root run and set a 110 amps
current

• Put 4 tacks at regular intervals adjusting 3 mm root gap between the pipes using spacers.
• Ensure that each tack ends with a key hole
• Check and ensure that the pipes are in line after tacking
• Set 110 amp for a 3 15mmø electrode for root run.
• Deposit the root run in flat position by without rotating the pipe

• Welding using the keyhole technique ensures root penetration.
• Remove slag from the root thoroughly.
• Deposit the second and third run using a 3.15 mm a electrodes ie the same as for the root run.
• Clean and inspect the joint

Skill Sequence

Pipe welding butt joint on MS pipe ø50mm and 5mm wall thickness

in 1G position
Objectives: At the end of this exercise you shall be able to
• prepare and weld butt joint on MS pipe in (IG) position.

Cut the pipes to the given size by a hacksaw.
Check the squares of the pipe end by using a try square (Fig 1) and file the pipe end so that it is square with the
pipe axis

Fig 1

Prepare 30 to 35 bevel on one end of each pipe, leaving 1.5 to 1.75 mm root face by grinding or by filing (Fig 2)

Switch ‘on’ the machine and adjust 110amp current for 3.15 mm medium coated M.S. electrode (B.I.S code
ER4211). Use DCEN polarity
Before tacking, align the pipes on V profile of an angle iron with 2 mm root gap (Fig 3) and tack them as shown
in Fig 4. Check the gap using a 2 mm rod.

150

CITS : C G & M - Welder - Exercise 36 CITS : C G & M - Welder - Exercise 36