120103a-bA Wire Feed Welding Equipment and Consumable Part A Flashcards

Wire Feed Welding Equipment and Consumables : Part A

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1
Q

To protect yourself from electrical shock when welding, what must you ensure?

A

Answer: Ensure that all electrical equipment is properly grounded.

Explanation: Proper grounding of electrical equipment is crucial to prevent electrical shocks, which can be dangerous or even fatal. Grounding provides a safe path for electricity to be discharged, reducing the risk of electric shock.

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2
Q

What are the first two signs of oxygen deficiency?

A

Answer: Dizziness and euphoria.

Explanation: Oxygen deficiency in the welding environment can lead to dizziness and euphoria as early symptoms. This condition arises when shielding gases used in welding displace the oxygen in the air, creating a hazardous environment that can affect brain function and consciousness.

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3
Q

What shade of filter plate do AWS and CSA recommend as the minimum?

A

Answer: #10.

Explanation: The American Welding Society (AWS) and the Canadian Standards Group (CSA) recommend a minimum filter plate shade of #10 for welders’ helmets. This shade helps protect the eyes from intense light and radiation produced during welding, which can cause eye damage.

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4
Q

What is the primary function of shielding gas?

A

Answer: To shield the molten weld metal from atmospheric contamination.

Explanation: Shielding gases are used in welding to protect the molten weld pool from atmospheric gases, such as oxygen and nitrogen, that can cause defects like porosity and weak welds. These gases create a protective envelope around the weld area.

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5
Q

List the two outputs produced by common welding sources.

A

Answer: Constant current (CC) and constant voltage (CV).

Explanation: Welding power sources typically provide either constant current (CC) or constant voltage (CV). CC is used where the current remains steady despite changes in voltage, suitable for processes like SMAW and GTAW. CV is used in processes like GMAW, where voltage is kept constant to maintain a stable arc, despite fluctuations in current.

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6
Q

What do flowmeters control?

A

Answer: Flowmeters control the rate of flow of shielding gas to the gun nozzle.

Explanation: Flowmeters are essential for regulating the amount of shielding gas delivered to the welding area. Proper flow rate ensures adequate protection of the molten weld pool from atmospheric contamination while avoiding excessive gas usage.

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7
Q

What should your protective clothing characteristics be when welding with GMAW, and why?

A

Answer: Clothing should be dark, tightly knit 100% cotton to reduce reflected light radiation and promote fire-resistance.

Explanation: Dark, tightly knit cotton clothing minimizes the risk of burns from sparks and reduces light reflection, which can cause glare and impair vision. Cotton is preferred for its fire-resistant properties compared to synthetic materials.

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8
Q

What precautions should you take when welding under wet weather conditions or standing on wet surfaces?

A

Answer: Protect yourself from electrical shock hazards by wearing rubber boots with dry socks and gloves.

Explanation: Wet conditions greatly increase the risk of electrical shock. Rubber boots and gloves provide insulation, reducing the risk of electricity passing through the body, which can be fatal.

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9
Q

Name the two toxic gases that the ultraviolet light from welding will produce.

A

Answer: Ozone and Phosgene gas (from chlorinated hydrocarbon degreasers).

Explanation: Ultraviolet light from welding can react with oxygen to form ozone and with chlorinated solvents to form phosgene gas, both of which are highly toxic and dangerous to health.

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10
Q

How might using a shielding gas during welding affect air quality?

A

Answer: Shielding gases in sufficient quantities displace enough air to render the work area oxygen deficient. Dizziness or euphoria is usually the first sign of oxygen deficiency.

Explanation: High concentrations of shielding gases can displace oxygen in the air, leading to an oxygen-deficient environment. This can cause symptoms like dizziness or euphoria, indicating a need for proper ventilation and air monitoring.

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11
Q

List the essential equipment components always required to set up a wire feed outfit.

A

Answer: Power source, wire feeder, gun and cable assembly, spooled filler wire, shielding gas, and gas control equipment.

Explanation: These components are fundamental for wire feed welding setups. The power source generates the welding current, the wire feeder controls the filler wire feed, the gun and cable assembly deliver the current and wire to the weld, and the shielding gas and control equipment regulate gas flow to protect the weld pool.

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12
Q

What three properties are wire feed welding power source ratings based on?

A

Answer: Amperage, Voltage, Duty cycle.

Explanation: Power source ratings are based on these properties to determine their suitability for various welding applications. Amperage and voltage define the power source’s capacity, while the duty cycle indicates how long it can operate continuously at a given amperage and voltage without overheating.

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13
Q

What is the most common current that the wire processes use?
a) Constant current (CC)
b) Constant voltage (constant potential)
c) Alternating current (AC)
d) High frequency (hf)

A

Answer: b) Constant voltage (constant potential).

Explanation: Constant voltage systems are commonly used in wire welding processes as they maintain a relatively stable voltage level, which is crucial for a consistent arc and weld quality.

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14
Q

A CV power source increases or decreases the welding current to account for what?

A

Answer: Voltage fluctuations.

Explanation: A Constant Voltage (CV) power source adjusts the welding current to compensate for voltage fluctuations. This ensures a stable arc and consistent welding quality, even if the voltage changes.

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15
Q

What is preset by the voltage control on the power source?

A

Answer: Desired arc length.

Explanation: The voltage control on a power source is used to preset the desired arc length. Voltage directly influences arc length, with higher voltages producing longer arcs and vice versa.

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16
Q

Why is a constant voltage constant speed system preferred over constant current
voltage sensing systems?

a) Smoother arc characteristics and consistent bum off rate
b) Higher deposition rates
c) Easier arc starting properties.
d) The ability to have a longer stick out length for visibility

A

Answer: a) Smoother arc characteristics and consistent burn off rate.

Explanation: A constant voltage constant speed system is preferred because it provides smoother arc characteristics and a consistent rate of electrode burn-off. This results in more uniform welds and easier control of the welding process.

17
Q

What must a constant current machine be equipped with to be used for wire processes?

A

Answer: A voltage sensing unit.

Explanation: For wire processes, a constant current machine must have a voltage sensing unit. This unit is necessary to maintain stable arc conditions and adjust the current in response to changes in arc length, which is crucial for wire feed processes.

18
Q

What is the maximum distance you can push wire using a push feed system?

A

Answer: 4.5 m (15 ft).

Explanation: In a push feed system, the drive rolls in the wire feeder push the wire through a conduit to the welding gun. The maximum effective distance for this system is typically 4.5 meters, beyond which feeding issues may occur due to resistance in the conduit.

19
Q

What is the most common pull feed system?

A

Answer: Spool on the gun.

Explanation: The most common pull feed system involves having a spool of wire directly on the welding gun. This system is beneficial for welding soft or small diameter wires, as the shorter feed path reduces the chance of wire tangling and feeding issues.

20
Q

What is the maximum distance you can feed wire through a push-pull system?

A

Answer: 15.2 m (50 ft).

Explanation: Push-pull systems combine push and pull mechanisms, allowing for longer feeding distances. In this system, wire can be effectively fed up to 15.2 meters, making it suitable for applications where the welder needs to move over larger distances.

21
Q

Which system maintains arc length by automatically adjusting the amperage output as the electrode extension changes?

A

Answer: Constant speed wire feeder.

Explanation: A constant speed wire feeder maintains a consistent wire feed rate, automatically adjusting the amperage to keep the arc length constant. This system helps in achieving a stable arc and consistent welding quality, especially important in automated welding processes.

22
Q

List the essential components of a typical air-cooled gun.

A

Answer: Gun body, Gas diffuser, Contact tube, Nozzle, Cable assembly including conduit and liner.

Explanation: A typical air-cooled welding gun comprises these components:
Gun Body: The main structure of the gun.
Gas Diffuser: Disperses shielding gas into the welding area.
Contact Tube: Also known as a contact tip, it conducts welding current to the wire.
Nozzle: Directs shielding gas and protects the welding area.
Cable Assembly with Conduit and Liner: Transmits current, wire, and shielding gas from the wire feeder to the gun.

23
Q

What maximum weight can you get in a bulk drum?
a) 250 lb
b) 500 lb
c) 750 lb
d) 1000 lb

A

Answer: d)1000 lb.

Explanation: Bulk drums for welding wires can have a maximum weight of 1000 pounds. This large capacity is beneficial for high-volume welding operations, reducing the frequency of wire changes and thus improving efficiency.

24
Q

How should you store unused wire or open filler metal packaging?

How should you store unused wire or open filler metal packaging?
a) Keep them covered and away from humid environments
b) Loosely set to the side for easy access
c) Stacked in a designated area on the floor
d) Store all filler metals so they are readily available

A

Answer: a) Keep them covered and away from a humid environment.

Explanation: Unused welding wire or open filler metal packaging should be stored in a way that protects them from humidity and other environmental factors that could lead to corrosion or contamination. Proper storage ensures the wire maintains its quality and performance.

25
Q

List five (5) identification factors that you would find listed on packaging.

A

Answer: Classification, Wire size, Spool size, Batch number, Manufacturer.

Explanation:
Classification: Specifies the wire type and its applicable welding standards.
Wire Size: Indicates the diameter of the wire, crucial for selecting the appropriate wire for different welding applications.
Spool Size: Provides information about the amount of wire on the spool.
Batch Number: Useful for quality control and traceability.
Manufacturer: Identifies the producer of the wire, important for quality assurance and compatibility with welding equipment.

26
Q

What are the basic modes of metal transfer in wire feed processes?

A

Answer: Short-circuiting transfer, Globular transfer, Spray transfer, Pulsed-spray transfer, Modified short-circuit transfer.

Explanation:
Short-Circuiting Transfer: Involves the wire touching the weld pool and creating a short circuit. Used for thin materials and all positions.
Globular Transfer: Characterized by large droplets, often avoided in GMAW due to spatter and poor weld appearance.
Spray Transfer: Produces a stream of small droplets and is used for thicker materials, typically in flat or horizontal positions.
Pulsed-Spray Transfer: A variation of spray transfer that uses pulsing current to lower heat input, allowing for welding thinner materials in all positions.
Modified Short-Circuit Transfer: An advanced method that controls the transfer of metal to minimize spatter and improve control.

27
Q

What position(s) can short circuit metal transfer be used in?
a) Flat position
b) Horizontal position
c) Vertical downhill
d) All the above

A

Answer: d) All the above (flat, horizontal, vertical).

Explanation: Short circuit transfer is versatile and can be used in all welding positions due to its controlled heat input and adaptability to various joint configurations.

28
Q

Which mode of metal transfer is avoided with GMAW due to increased spatter and
poor weld metal appearance?
a) Globular
b) Short circuiting
c) Spray
d) Pulsed spray

A

Answer: a) Globular transfer.

Explanation: Globular transfer is typically avoided in Gas Metal Arc Welding (GMAW) because it produces large, irregular droplets that lead to increased spatter and poor weld appearance.

29
Q

What position(s) is spray arc metal transfer most used in?
a) Flat position only
b) Horizontal and flat position
c) Vertical downhill position only
d) All positions

A

Answer: b) Flat and horizontal positions.

Explanation: Spray arc transfer is commonly used in flat and horizontal positions due to its high deposition rates and deep penetration, which are ideal for thicker materials in these orientations.

30
Q

List six (6) operating variables in a wire feed system that impact welding quality.

A

Answer: Voltage, Amperage, Polarity, Electrode extension (stickout), Inductance, Slope.

Explanation:
Voltage: Affects arc length and heat input.
Amperage: Determines the rate of electrode melting.
Polarity: Influences penetration and bead shape.
Electrode Extension (Stickout): Impacts resistance heating and melting rate.
Inductance: Modulates the arc characteristics, especially in short-circuiting transfer.
Slope: Controls the rate of current increase, affecting spatter in short-circuiting transfer.