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Gas Metal Arc Welding

Instructions:

Answer 50 questions in 15 minutes.
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Match each statement with the correct term.
Don't refresh. All questions and answers are randomly picked and ordered every time you load a test.

This is a study tool. The 3 wrong answers for each question are randomly chosen from answers to other questions. So, you might find at times the answers obvious, but you will see it re-enforces your understanding as you take the test each time.

1. In the GMAW process what does amperage control?
Welding Current - Filler wire diameter - arc length - type of shielding - position of the weld
Penetration and burn - off rate of the electrode
5.8 to 12.5 L/min
Generally not as accurate

2. What type of power source is used with a constant speed wire feeder?
When the filler wire is in direct contract with the base metal
5.8 to 12.5 L/min
Constant voltage (CV)
Constant current (CC)

3. What is the preferred drive roll design for solid wires?
V groove or U groove
Gives arc voltage values to the control system of the feeder
1/4 inch to 1/2 inch
To limit the short circuiting current so that spatter is reduced

4. What is the purpose of the pick- up lead on a voltage sensing wire feeder?
To prevent leakage - Carbon Dioxide (CO2)
85%
Gives arc voltage values to the control system of the feeder
The time rate of response for the current rise and fall

5. What processes are constant current (CC) power sources designed to be used with?
To prevent leakage - Carbon Dioxide (CO2)
Duty cycle
SMAW - GTAW
Wire feed speed - Voltage control

6. Why must CO2 cylinders be used in the vertical position?
Welding Current - Filler wire diameter - arc length - type of shielding - position of the weld
Wire feeds smoothly (yet will slip should a problem occur in the gun)
To prevent drawing of liquid CO2 (Carbon Dioxide)
Pressure - The rate of flow of a shielding gas

7. What is the recommended electrode stick- out for .035 solid wire?
1/4 inch to 1/2 inch
Duty cycle
Minutes of elapsed time continually run (out of 10 minutes)
Increasing inductance increases puddle fluidity - improves penatration - makes the bead flatter and smoother - and reduces spatter. To much inductance though will create erratic starts

8. When is the metal transferred with short circuit transfer?
Pressure vessels and the piping industry
When the filler wire is in direct contract with the base metal
Spatter problems and poor weld appearance
Flux cored wires

9. A machine with a 70% duty cycle can run at its max for 7 minutes with a cooling cycle of only _ minutes.
Constant current (CC)
When the filler wire is in direct contract with the base metal
To limit the short circuiting current so that spatter is reduced
3

10. List the factors that determine the mode of metal transfer
Gas metal arc welding
1/4 inch to 1/2 inch
Spatter problems and poor weld appearance
Welding Current - Filler wire diameter - arc length - type of shielding - position of the weld

11. Give a description of 'pinch effect'
Dry ice can form within the flow control openings and cause blockage of shielding gas
12 to 22 arc volts
Puddle fluidity
Molten metal is separated from the end of the filler wire by a squeezing force created by a magnetic field

12. What is the effect of too much slope?
Electricaly operated valves that control the flow of shielding gas to the weld zone. The control switch located on the gun
Insufficient current to melt the wire off cleanly
By there current carrying capacity
Compressed gas cylinder - Liquid filled cylinder - or a Liquid bulk system

13. What is the key advantage of short circuiting transfer?
Minimum distortion due to low heat input
Motor driven generators - Transformer rectifiers - and Inverter designs
1/4 inch to 1/2 inch
By there current carrying capacity

14. How are GMAW guns rated?
By there current carrying capacity
Flux cored wires
Wire feeds smoothly (yet will slip should a problem occur in the gun)
The Arc voltage

15. What is the purpose of a regulator and what does it indicate on its gauges?
Reducing the gas source pressure to a constant working pressure
5.8 to 12.5 L/min
85%
Cause flaking - which can clog the liner and contact tube

16. What does the abbreviation NEMA stand for?
Reducing the gas source pressure to a constant working pressure
National Electrical Manufactures Association
Insufficient current to melt the wire off cleanly
5.8 to 12.5 L/min

17. What effect does increasing and decreasing the inductance have on the weld?
To limit the short circuiting current so that spatter is reduced
To prevent drawing of liquid CO2 (Carbon Dioxide)
DCEP (Direct Current Electrode Positive) Reverse Polarity
Increasing inductance increases puddle fluidity - improves penatration - makes the bead flatter and smoother - and reduces spatter. To much inductance though will create erratic starts

18. List the three methods of metal transfer with GMAW
Wire feeds smoothly (yet will slip should a problem occur in the gun)
Minutes of elapsed time continually run (out of 10 minutes)
Short- circuiting transfer - Globular transfer - Spray transfer
Insufficient current to melt the wire off cleanly

19. What term is used to describe when the workpiece is hooked to the negative pole on the power source?
(DCEP) Direct Current Electrode Positive or Reverse polarity
5.8 to 12.5 L/min
AWS and CSA
Wire feed speed - Voltage control

20. In the GMAW process what does voltage control?
Minimum distortion due to low heat input
Puddle fluidity
Heat input is less than spray transfer - resulting in less distortion - Used in all positions due to controlling the weld metal freeze
Reducing the gas source pressure to a constant working pressure

21. With straight polarity where is 2/3 of the arc energy?
Constant voltage (CV)
Welding Current - Filler wire diameter - arc length - type of shielding - position of the weld
Duty cycle
The negative side of a welding unit

22. Why is a fiber washer required and what cylinder gas requires it?
1/4 inch to 1/2 inch
Electricaly operated valves that control the flow of shielding gas to the weld zone. The control switch located on the gun
Controls the rate of flow of a shielding gas to the gun nozzle
To prevent leakage - Carbon Dioxide (CO2)

23. What current and polarity is generally used with GMAW?
DCEP (Direct Current Electrode Positive) Reverse Polarity
The time rate of response for the current rise and fall
Short- circuiting transfer - Globular transfer - Spray transfer
Guns

24. What controls the wire speed on a voltage sensing wire feeder?
The Arc voltage
12 to 22 arc volts
20 to 200 times per second
SMAW - GTAW

25. What is the required arc voltage used for short circuit transfer?
To prevent leakage - Carbon Dioxide (CO2)
12 to 22 arc volts
To prevent drawing of liquid CO2 (Carbon Dioxide)
The time rate of response for the current rise and fall

26. What 2 controls are found on a GMAW set- up?
Insufficient current to melt the wire off cleanly
To prevent leakage - Carbon Dioxide (CO2)
Minimum distortion due to low heat input
Wire feed speed - Voltage control

27. What does the term GMAW identify?
Aluminum wire
Gas metal arc welding
Insufficient current to melt the wire off cleanly
Cause flaking - which can clog the liner and contact tube

28. What power sources are used with the GMAW Process?
Increasing inductance increases puddle fluidity - improves penatration - makes the bead flatter and smoother - and reduces spatter. To much inductance though will create erratic starts
Generally not as accurate
Motor driven generators - Transformer rectifiers - and Inverter designs
Reducing the gas source pressure to a constant working pressure

29. What is the maximum distance that hard wire can be successfully pushed?
Cause flaking - which can clog the liner and contact tube
15 feet (4.5 meters)
To limit the short circuiting current so that spatter is reduced
Controls the rate of flow of a shielding gas to the gun nozzle

30. What is an advantage of pulsed arc transfer with GMAW?
Aluminum wire
85%
Dry ice can form within the flow control openings and cause blockage of shielding gas
Heat input is less than spray transfer - resulting in less distortion - Used in all positions due to controlling the weld metal freeze

31. What does voltage do in an electrical circuit?
Molten metal is separated from the end of the filler wire by a squeezing force created by a magnetic field
Dry ice can form within the flow control openings and cause blockage of shielding gas
The time rate of response for the current rise and fall
Voltage is the force that overcomes resistance to allow amperage flow

32. What would be an indication that the drive roll pressure is adjusted correctly?
Wire feeds smoothly (yet will slip should a problem occur in the gun)
Flux cored wires
To prevent drawing of liquid CO2 (Carbon Dioxide)
Gives arc voltage values to the control system of the feeder

33. A pull type drive system is usually used on what type of material?
Penetration and burn - off rate of the electrode
Aluminum wire
To prevent leakage - Carbon Dioxide (CO2)
The time rate of response for the current rise and fall

34. What is the disadvantage of the gauge preset type of regulator/flowmeter?
Generally not as accurate
12 to 22 arc volts
Wire feeds smoothly (yet will slip should a problem occur in the gun)
Wire feed speed - Voltage control

35. What type of power source is commonly used with a voltage sensing wire feeder?
Constant current (CC)
Penetration and burn - off rate of the electrode
Welding process that joins metals by heating them with an electric arc
Guns

36. What output on the welding machine is used to rate the duty cycle?
Power source - wire feeder - welding gun - Spooled filler wire - Shielding gas - and a ground
Minutes of elapsed time continually run (out of 10 minutes)
Spatter problems and poor weld appearance
Increasing inductance increases puddle fluidity - improves penatration - makes the bead flatter and smoother - and reduces spatter. To much inductance though will create erratic starts

37. What is the purpose of the shielding gas used in GMAW?
Higher 26 to 35 arc volts
Shielding the molten weld metal from atmospheric contamination
Duty cycle
If you dont know this check your phone

38. List 3 forms compressed gases may be supplied for welding
Power source - wire feeder - welding gun - Spooled filler wire - Shielding gas - and a ground
Voltage is the force that overcomes resistance to allow amperage flow
Compressed gas cylinder - Liquid filled cylinder - or a Liquid bulk system
Welding process that joins metals by heating them with an electric arc

39. Regulators control_____________ flowmeters SHOW____________.
Insufficient current to melt the wire off cleanly
Pressure - The rate of flow of a shielding gas
DCEP (Direct Current Electrode Positive) Reverse Polarity
15 feet (4.5 meters)

40. What happens when the electrode extension is increased?
National Electrical Manufactures Association
Spatter problems and poor weld appearance
3
The resistace to electrical current flow increases with it. Causing the electrode to heat

41. List the basic equipment requirements for the GMAW process
Power source - wire feeder - welding gun - Spooled filler wire - Shielding gas - and a ground
Puddle fluidity
The time rate of response for the current rise and fall
15 feet (4.5 meters)

42. Why is globular transfer generally avoided with GMAW?
15 feet (4.5 meters)
Spatter problems and poor weld appearance
Electricaly operated valves that control the flow of shielding gas to the weld zone. The control switch located on the gun
Gas metal arc welding

43. What 2 organizations designate specifications for GMAW wires?
Aluminum wire
Guns
Motor driven generators - Transformer rectifiers - and Inverter designs
AWS and CSA

44. What is the main purpose of 'slope'?
To limit the short circuiting current so that spatter is reduced
...
When the filler wire is in direct contract with the base metal
Gives arc voltage values to the control system of the feeder

45. What is another term for electrode holders for GMAW?
Guns
1/4 inch to 1/2 inch
Cause flaking - which can clog the liner and contact tube
3

46. How many times per second does short circuiting take place?
The resistace to electrical current flow increases with it. Causing the electrode to heat
20 to 200 times per second
Wire feed speed
The time rate of response for the current rise and fall

47. What does inductance control?
1/4 inch to 1/2 inch
15 feet (4.5 meters)
The time rate of response for the current rise and fall
Duty cycle

48. A 10 minute cycle of welding time vs cooling time a given machine can handle.
To prevent leakage - Carbon Dioxide (CO2)
20 to 200 times per second
Duty cycle
Shielding the molten weld metal from atmospheric contamination

49. Why is the term GMAW preferred over MIG or MAG?
Spatter problems and poor weld appearance
Push type: Wire is fed by a set of drive rolls located in the wire feed unit - Pull type: Drive rolls mounted in the gun itself - Push- pull type: Combination of the two
Cause flaking - which can clog the liner and contact tube
These terms are quite restrictive and often technically incorrect

50. Give a brief description of the GMAW process
Welding process that joins metals by heating them with an electric arc
Compressed gas cylinder - Liquid filled cylinder - or a Liquid bulk system
1/4 inch to 1/2 inch
Guns