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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. A 10 minute cycle of welding time vs cooling time a given machine can handle.
The negative side of a welding unit
Duty cycle
Controls the rate of flow of a shielding gas to the gun nozzle
AWS and CSA

2. Is the arc voltage for spray transfer higher or lower than that used for short circuit transfer?
Increasing inductance increases puddle fluidity - improves penatration - makes the bead flatter and smoother - and reduces spatter. To much inductance though will create erratic starts
If you dont know this check your phone
Higher 26 to 35 arc volts
Aluminum wire

3. Why is the term GMAW preferred over MIG or MAG?
DCEP (Direct Current Electrode Positive) Reverse Polarity
These terms are quite restrictive and often technically incorrect
Shielding the molten weld metal from atmospheric contamination
If you dont know this check your phone

4. What is the purpose of the pick- up lead on a voltage sensing wire feeder?
Constant current (CC)
Gives arc voltage values to the control system of the feeder
Reducing the gas source pressure to a constant working pressure
Generally not as accurate

5. What does the wire feeder control?
Speed of the feed motor and - starting / stopping electrode feed
Electricaly operated valves that control the flow of shielding gas to the weld zone. The control switch located on the gun
Dry ice can form within the flow control openings and cause blockage of shielding gas
Reducing the gas source pressure to a constant working pressure

6. In the GMAW process what does voltage control?
Duty cycle
If you dont know this check your phone
Puddle fluidity
12 to 22 arc volts

7. How many times per second does short circuiting take place?
Molten metal is separated from the end of the filler wire by a squeezing force created by a magnetic field
3
Constant voltage (CV)
20 to 200 times per second

8. What type of power source is used with a constant speed wire feeder?
Constant voltage (CV)
Electricaly operated valves that control the flow of shielding gas to the weld zone. The control switch located on the gun
Heat input is less than spray transfer - resulting in less distortion - Used in all positions due to controlling the weld metal freeze
Penetration and burn - off rate of the electrode

9. What happens when the electrode extension is increased?
Minimum distortion due to low heat input
The resistace to electrical current flow increases with it. Causing the electrode to heat
Insufficient current to melt the wire off cleanly
DCEP (Direct Current Electrode Positive) Reverse Polarity

10. What current and polarity is generally used with GMAW?
Reducing the gas source pressure to a constant working pressure
DCEP (Direct Current Electrode Positive) Reverse Polarity
5.8 to 12.5 L/min
Minimum distortion due to low heat input

11. What is the disadvantage of the gauge preset type of regulator/flowmeter?
Puddle fluidity
The resistace to electrical current flow increases with it. Causing the electrode to heat
Generally not as accurate
5.8 to 12.5 L/min

12. What is the key advantage of short circuiting transfer?
Speed of the feed motor and - starting / stopping electrode feed
The time rate of response for the current rise and fall
Minimum distortion due to low heat input
To limit the short circuiting current so that spatter is reduced

13. What is the maximum distance that hard wire can be successfully pushed?
Aluminum wire
(DCEP) Direct Current Electrode Positive or Reverse polarity
Generally not as accurate
15 feet (4.5 meters)

14. What is an advantage of pulsed arc transfer with GMAW?
Pressure vessels and the piping industry
Welding process that joins metals by heating them with an electric arc
12 to 22 arc volts
Heat input is less than spray transfer - resulting in less distortion - Used in all positions due to controlling the weld metal freeze

15. What effect does increasing and decreasing the inductance have on the weld?
Increasing inductance increases puddle fluidity - improves penatration - makes the bead flatter and smoother - and reduces spatter. To much inductance though will create erratic starts
The resistace to electrical current flow increases with it. Causing the electrode to heat
Controls the rate of flow of a shielding gas to the gun nozzle
The time rate of response for the current rise and fall

16. What controls the wire speed on a voltage sensing wire feeder?
The Arc voltage
Guns
Minimum distortion due to low heat input
Constant voltage (CV)

17. What is the recommended electrode stick- out for .035 solid wire?
Higher 26 to 35 arc volts
1/4 inch to 1/2 inch
Welding process that joins metals by heating them with an electric arc
Wire feed speed

18. What is the preferred drive roll design for solid wires?
Electricaly operated valves that control the flow of shielding gas to the weld zone. The control switch located on the gun
V groove or U groove
15 feet (4.5 meters)
Compressed gas cylinder - Liquid filled cylinder - or a Liquid bulk system

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
Voltage is the force that overcomes resistance to allow amperage flow
Duty cycle
Welding process that joins metals by heating them with an electric arc

20. What type of power source is commonly used with a voltage sensing wire feeder?
15 feet (4.5 meters)
Increasing inductance increases puddle fluidity - improves penatration - makes the bead flatter and smoother - and reduces spatter. To much inductance though will create erratic starts
Constant current (CC)
Electricaly operated valves that control the flow of shielding gas to the weld zone. The control switch located on the gun

21. What power sources are used with the GMAW Process?
If you dont know this check your phone
National Electrical Manufactures Association
Motor driven generators - Transformer rectifiers - and Inverter designs
Gives arc voltage values to the control system of the feeder

22. What controls amperage when using GMAW?
V groove or U groove
To prevent drawing of liquid CO2 (Carbon Dioxide)
DCEP (Direct Current Electrode Positive) Reverse Polarity
Wire feed speed

23. Draw a typical volt/amp curve that would be found with a power source designed for SMAW or GTAW
Generally not as accurate
If you dont know this check your phone
Duty cycle
15 feet (4.5 meters)

24. What is the purpose of a regulator and what does it indicate on its gauges?
V groove or U groove
Controls the rate of flow of a shielding gas to the gun nozzle
The negative side of a welding unit
Reducing the gas source pressure to a constant working pressure

25. Why is a line heater required when using GMAW?
SMAW - GTAW
Speed of the feed motor and - starting / stopping electrode feed
Dry ice can form within the flow control openings and cause blockage of shielding gas
Cause flaking - which can clog the liner and contact tube

26. What is the minimum % value of argon that must be present to use the spray transfer method of GMAW?
85%
The negative side of a welding unit
Short- circuiting transfer - Globular transfer - Spray transfer
These terms are quite restrictive and often technically incorrect

27. When using flat drive rolls with too much pressure on copper coated solid wires what problem could take place?
Cause flaking - which can clog the liner and contact tube
Gives arc voltage values to the control system of the feeder
Shielding the molten weld metal from atmospheric contamination
Puddle fluidity

28. What is another term for electrode holders for GMAW?
Guns
Power source - wire feeder - welding gun - Spooled filler wire - Shielding gas - and a ground
Wire feeds smoothly (yet will slip should a problem occur in the gun)
SMAW - GTAW

29. What does inductance control?
The time rate of response for the current rise and fall
Dry ice can form within the flow control openings and cause blockage of shielding gas
Higher 26 to 35 arc volts
Generally not as accurate

30. List several industries that would use GMAW
Controls the rate of flow of a shielding gas to the gun nozzle
DCEP (Direct Current Electrode Positive) Reverse Polarity
Pressure vessels and the piping industry
By there current carrying capacity

31. What 2 controls are found on a GMAW set- up?
Duty cycle
Constant- speed wire feeders and Voltage- sennsing wire feeders
Wire feed speed - Voltage control
3

32. When is the metal transferred with short circuit transfer?
National Electrical Manufactures Association
Shielding the molten weld metal from atmospheric contamination
Constant voltage (CV)
When the filler wire is in direct contract with the base metal

33. What are the 2 types of wire feeders available?
Constant- speed wire feeders and Voltage- sennsing wire feeders
Pressure vessels and the piping industry
Flux cored wires
Constant current (CC)

34. How are GMAW guns rated?
Molten metal is separated from the end of the filler wire by a squeezing force created by a magnetic field
15 feet (4.5 meters)
By there current carrying capacity
If you dont know this check your phone

35. List the basic equipment requirements for the GMAW process
Power source - wire feeder - welding gun - Spooled filler wire - Shielding gas - and a ground
Speed of the feed motor and - starting / stopping electrode feed
To prevent drawing of liquid CO2 (Carbon Dioxide)
Duty cycle

36. Regulators control_____________ flowmeters SHOW____________.
Pressure - The rate of flow of a shielding gas
(DCEP) Direct Current Electrode Positive or Reverse polarity
15 feet (4.5 meters)
Constant current (CC)

37. Why is globular transfer generally avoided with GMAW?
Spatter problems and poor weld appearance
Power source - wire feeder - welding gun - Spooled filler wire - Shielding gas - and a ground
Gas metal arc welding
Constant- speed wire feeders and Voltage- sennsing wire feeders

38. What does a flowmeter do and what does it measure?
To prevent drawing of liquid CO2 (Carbon Dioxide)
Controls the rate of flow of a shielding gas to the gun nozzle
By there current carrying capacity
Constant voltage (CV)

39. Give a brief description of the GMAW process
Wire feed speed - Voltage control
Generally not as accurate
Gives arc voltage values to the control system of the feeder
Welding process that joins metals by heating them with an electric arc

40. A pull type drive system is usually used on what type of material?
The negative side of a welding unit
Constant voltage (CV)
Aluminum wire
Minutes of elapsed time continually run (out of 10 minutes)

41. List 3 forms compressed gases may be supplied for welding
20 to 200 times per second
Duty cycle
Compressed gas cylinder - Liquid filled cylinder - or a Liquid bulk system
Welding process that joins metals by heating them with an electric arc

42. What would be an indication that the drive roll pressure is adjusted correctly?
20 to 200 times per second
Wire feeds smoothly (yet will slip should a problem occur in the gun)
Insufficient current to melt the wire off cleanly
Controls the rate of flow of a shielding gas to the gun nozzle

43. What 2 organizations designate specifications for GMAW wires?
85%
Pressure vessels and the piping industry
Welding process that joins metals by heating them with an electric arc
AWS and CSA

44. List the factors that determine the mode of metal transfer
V groove or U groove
Welding Current - Filler wire diameter - arc length - type of shielding - position of the weld
20 to 200 times per second
Short- circuiting transfer - Globular transfer - Spray transfer

45. What does the abbreviation NEMA stand for?
National Electrical Manufactures Association
Gas metal arc welding
Higher 26 to 35 arc volts
Compressed gas cylinder - Liquid filled cylinder - or a Liquid bulk system

46. What is the main purpose of 'slope'?
Increasing inductance increases puddle fluidity - improves penatration - makes the bead flatter and smoother - and reduces spatter. To much inductance though will create erratic starts
To limit the short circuiting current so that spatter is reduced
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

47. List 3 wire drive systems and give a short description of each
Constant current (CC)
1/4 inch to 1/2 inch
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
Penetration and burn - off rate of the electrode

48. What output on the welding machine is used to rate the duty cycle?
Welding Current - Filler wire diameter - arc length - type of shielding - position of the weld
15 feet (4.5 meters)
Minutes of elapsed time continually run (out of 10 minutes)
Dry ice can form within the flow control openings and cause blockage of shielding gas

49. Why must CO2 cylinders be used in the vertical position?
To prevent drawing of liquid CO2 (Carbon Dioxide)
If you dont know this check your phone
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
Flux cored wires

50. What is the purpose of the shielding gas used in GMAW?
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
Shielding the molten weld metal from atmospheric contamination
(DCEP) Direct Current Electrode Positive or Reverse polarity