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WIRE WELDING

Welding technique

Set the correct parameters given for the base material, wire and shielding gas that are to be used. These parameters include: (1) Gas flow rate.

(2) Wire feed speed.

(3) Amperage or voltage setting. When setting the gas flow rate, allow the gas to flow for a while to ensure that the gas supply system is fully purged. If in doubt of the actual wire feed speed at a certain setting on the machine, this may be checked by pressing the torch micro-switch and initiate wire feed for exactly 6 seconds. Measure the wire length that has been fed, multiply by 10 and you will have feed rate per minute. When doing this remember to keep the wire away from contact with deck or workpiece. While feeding in this way the wire will be electrically live and an arc will occur if contact is made.

cold arc and insufficient gas shield and must be avoided.

Too short stickout may overheat the contact tip and will also allow more spatter to reach the nozzle. This may again cause turbulence in the gas flow, and insufficient shielding. When Flux Cored Arc Welding Self Shielded is to be used, a to short a stick out will give porosity.

Within limits, and depending on the characteristic of the power source, the welder may use the stick out to adjust the welding parameters while welding. Increasing stick out will: • decrease penetration. • increase deposition rate. • increase bead size.

• decrease bead width.

While welding the welder controls five variables; wire stickout (4), travel speed and direction (5), torch angles (6) and weaving (7).

Wire stickout

The stick-out is the distance from the end of the contact tip to the baseplate, including the arc length. This distance decides how long the current carrying part of the welding wire is to be. The electric resistance and voltage drop in the wire increases with increasing stickout. This voltage drop is part of what the equipment measures as arc voltage, and the welding current will decrease with increasing stickout and vice versa.

4.03

Too long stickout may result in too

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