Page 193 - CITS - Welder - Trade Practical

WELDER - CITS

• Set the joint in a flat position.
• Deposit root run by using a Ø1.2mm dia 150 amps.
Ensure an electrode angle of 45° with the 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 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 size.
• Inspect the weld for surface defects and sizes.

Skill Sequence

Set up and monitor GMAW welding machine & accessories

Objectives: At the end of this exercise you shall be able to
• set up and monitor GMAW welding machine & accessories.

Setting up of the CO machine: Fix the wire spool and take the wire through the guide tube, rollers, spiral and
2
contact tip at the end of the torch/gun.
Draw the wire from the spool, pass it on through the inlet wire guide, driver rollers and outlet wire guide.
The roller should not be over tightned to avoid flattening and peeling of copper coating on the wire. The wire is
further passed through the conduit liners with spring liners called spiral (Fig 1) to the welding torch outlet through
the contact tip.
The wire should not develop any bends (or) kinks while inserting.
The contact tip should be removed to facilitate easy flow of the wire from the Spiral and put in position into the
Torch later.
Start the welding machine after the machine is connected to the 3 phase supply mains.
Connect the welding torch to the positive terminal. The positive terminal influences deeper, wider weld penetration
with a good ripple formation.
Connecting the heater, regulator and flow meter: The inlet end of the CO gas heater is connected to the CO 2
2
cylinder. The heater should be connected to either 110V supply from the welding machine (or) 230V supply from
the mains.
This will help to avoid ice-forming (freezing) of the CO gas at regulator and flow meter. Fix a two stage regulator
2
using a flat spanner to the outlet end of the gas heater and ensure proper functioning of the dial gauges. Connect
finally the Flow meter, Gas hose to the welding torch/gun. Set an outflow pressure for CO gas to get a gas flow
2
of 8 to 10 LPM as required for the Dip Transfer mode.
Ensure to avoid leakage at all connections so as to get correct pressure at the nozzle end. This could be checked
by using soap-water solution. When used with correct gas flow rate a rapid cracking and hissing sound shall be
heard. Too little flow results in porosity and too high flow rate creates turbulances and in turn contaminates weld.
Setting up arc voltage, stickout and wire feed rate for dip transfer

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CITS : C G & M - Welder - Exercise 49 CITS : C G & M - Welder - Exercise 49