Questions and Answers
In GMAW, the shielding for the molten metal is accomplished through the use of?
GMAW is the abbreviation for?
In GMAW, insufficient gas flow can cause?
A worn contact tube results in?
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The benefit of copper coated electrode wires is?
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What type of power source is used for GMAW?
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In GMAW, which type of metal transfer is restricted to flat position and horizontal fillet welds?
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What type of electrode wire is used with GMAW?
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In GMAW, the amperage is controlled by adjusting the?
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In GMAW, electrode extension is defined as the distance from the?
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Which AWS electrode classification is correct for GMAW wire?
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Which of the following is considered an advantage of the GMAW process?
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Electric current is transferred to the electrode through the?
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What shielding gas or gas mixture will not produce spray transfer?
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The contact tube should be?
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What does the 7 indicate in the electrode classification ER70S-3?
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Excessive amounts of weld spatter in the nozzle may cause?
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Which of the following is not recommended when welding with short-circuiting transfer?
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Which of the following is not an advantage of the GMAW process?
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The transfer mode that uses low currents, low voltage, and small diameter electrode wire to weld in all positions is called?
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What positions and types of welds can be successfully welded using the spray transfer mode on carbon steel?
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Which shielding gas or gas mixture is most often used for welding carbon steel with the short-circuiting transfer mode?
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Which one of the gases listed below is inert?
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A constant voltage power supply is the most common type used for the GMAW process.
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The rate at which the arc moves along the weld joint is called the wire feed speed.
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A minimum of 80% Argon is required to achieve a spray transfer.
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In the electrode classification ER70S-6, the 'S' stands for short circuiting transfer.
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Study Notes
GMAW Overview
- GMAW stands for Gas Metal Arc Welding, utilizing both inert and reactive gases for shielding.
- A constant voltage power supply is typically used in the GMAW process.
Metal Transfer Techniques
- Spray transfer is essential for flat position and horizontal fillet welds.
- Short-circuiting transfer operates at low currents and is applicable for all positions, using small diameter wire.
- Pulsed and globular transfer methods exist but have specific applications.
Shielding Gases
- A minimum of 80% Argon is necessary for achieving spray transfer.
- The combination of 75% Argon and 25% Carbon Dioxide is commonly used for carbon steel in short-circuiting transfer.
- 100% CO2 does not produce spray transfer, while argon is classified as an inert gas.
Electrode Characteristics
- The electrode wire used in GMAW is solid and classified under AWS as ER70S-3.
- The "7" in ER70S-3 indicates a tensile strength of 70,000 psi.
- Copper-coated electrodes enhance performance by improving arc starts, increasing contact tip life, and providing better wire feeding.
Welding Parameters
- Amperage is controlled by adjusting the wire feed speed.
- Electrode extension measures the distance from the end of the contact tube to the tip of the wire.
- A worn contact tube can lead to poor arc starts and increased spatter issues.
Advantages and Disadvantages
- GMAW offers higher deposition rates, reduced electrode waste, and ease of use compared to manual welding processes.
- However, GMAW is not advantageous in windy conditions which can affect the shielding gas.
Common Issues and Solutions
- Insufficient gas flow leads to porosity in welds.
- Excessive spatter in the nozzle can compromise shielding effectiveness.
- Welding thick plates is not recommended when using short-circuiting transfer due to potential difficulties.
Miscellaneous Facts
- The contact tube must match the diameter of the wire for optimal performance.
- GMAW processes can weld both ferrous and nonferrous metals, making it versatile in application.
- Understanding shielding gas mixtures and their effects is crucial for successful GMAW.
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Description
This quiz focuses on key concepts related to Gas Metal Arc Welding (GMAW). Test your knowledge on the terminology, techniques, and definitions related to this welding process. Perfect for welding students and professionals preparing for exams.
