Question

apply and analyze

1. what is the difference in the electrode wire used in gmaw and fcaw?

answer:

1. what is the difference in the way fcaw - s and fcaw - g protect the weld?

answer:

1. how does a constant voltage power source self - adjust to maintain a constant arc length when the welding gun is moved closer to the work?

answer:

1. what is the purpose of the inch switch on the wire drive control panel?

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1. what shielding gases are used for fcaw - g?

answer:

1. list two precautions to be taken when storing gascylinders.

answer:

Explanation:

1. In GMAW (Gas - Metal Arc Welding), the electrode wire is solid and requires an external shielding gas. In FCAW (Flux - Cored Arc Welding), the electrode wire is flux - cored, which contains flux within the wire and may or may not require an additional shielding gas depending on the type.
2. FCAW - S (Self - Shielded Flux - Cored Arc Welding) relies on the flux within the wire to produce shielding gases and slag to protect the weld. FCAW - G (Gas - Shielded Flux - Cored Arc Welding) uses an external shielding gas in addition to the flux in the wire for better weld protection.
3. When the welding gun is moved closer to the work, the resistance in the arc decreases. A constant voltage power source increases the current to maintain a constant arc length as per Ohm's law (V = IR, where V is constant, so if R decreases, I increases).
4. The inch switch on the wire drive control panel is used to feed a short length of electrode wire manually. This is useful for tasks like starting a weld, checking wire feed, or adjusting the wire position.
5. Common shielding gases used for FCAW - G include carbon dioxide ($CO_2$), argon - carbon dioxide mixtures (e.g., 75% Ar and 25% $CO_2$), which provide good arc stability and weld quality.
6. Precautions when storing gas cylinders: Keep them in a well - ventilated area to prevent gas accumulation and potential asphyxiation or explosion hazards; Store them in an upright position to prevent tipping and damage to the cylinder valves.

Answer:

1. In GMAW, solid electrode wire with external shielding gas; in FCAW, flux - cored wire, may or may not need additional shielding gas.
2. FCAW - S uses flux - generated shielding; FCAW - G uses external shielding gas plus flux.
3. Increases current as resistance in arc decreases to maintain constant arc length.
4. Manually feeds a short length of electrode wire.
5. $CO_2$, argon - $CO_2$ mixtures.
6. Keep in well - ventilated area; store upright.