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Gas Metal Arc Welding

Instructions:

Answer 50 questions in 30 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. What term is used to describe when the workpiece is hooked to the negative pole on the power source?
15 feet (4.5 meters)
12 to 22 arc volts
The Arc voltage
(DCEP) Direct Current Electrode Positive or Reverse polarity

2. What are the 2 types of wire feeders available?
Constant- speed wire feeders and Voltage- sennsing wire feeders
Higher 26 to 35 arc volts
The Arc voltage
To limit the short circuiting current so that spatter is reduced

3. What does a flowmeter do and what does it measure?
Generally not as accurate
Controls the rate of flow of a shielding gas to the gun nozzle
V groove or U groove
3

4. Regulators control_____________ flowmeters SHOW____________.
DCEP (Direct Current Electrode Positive) Reverse Polarity
Pressure - The rate of flow of a shielding gas
Constant current (CC)
The Arc voltage

5. A 10 minute cycle of welding time vs cooling time a given machine can handle.
Duty cycle
If you dont know this check your phone
1/4 inch to 1/2 inch
Cause flaking - which can clog the liner and contact tube

6. What controls amperage when using GMAW?
15 feet (4.5 meters)
Dry ice can form within the flow control openings and cause blockage of shielding gas
If you dont know this check your phone
Wire feed speed

7. Why is globular transfer generally avoided with GMAW?
Minutes of elapsed time continually run (out of 10 minutes)
Wire feeds smoothly (yet will slip should a problem occur in the gun)
5.8 to 12.5 L/min
Spatter problems and poor weld appearance

8. What is another term for electrode holders for GMAW?
(DCEP) Direct Current Electrode Positive or Reverse polarity
Duty cycle
Molten metal is separated from the end of the filler wire by a squeezing force created by a magnetic field
Guns

9. List the basic equipment requirements for the GMAW process
Constant- speed wire feeders and Voltage- sennsing wire feeders
Wire feed speed - Voltage control
Power source - wire feeder - welding gun - Spooled filler wire - Shielding gas - and a ground
To prevent drawing of liquid CO2 (Carbon Dioxide)

10. Why is a line heater required when using GMAW?
Dry ice can form within the flow control openings and cause blockage of shielding gas
Generally not as accurate
SMAW - GTAW
Gives arc voltage values to the control system of the feeder

11. List the factors that determine the mode of metal 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
AWS and CSA
Welding Current - Filler wire diameter - arc length - type of shielding - position of the weld
Minutes of elapsed time continually run (out of 10 minutes)

12. What is the disadvantage of the gauge preset type of regulator/flowmeter?
(DCEP) Direct Current Electrode Positive or Reverse polarity
Generally not as accurate
15 feet (4.5 meters)
Power source - wire feeder - welding gun - Spooled filler wire - Shielding gas - and a ground

13. What does the abbreviation NEMA stand for?
National Electrical Manufactures Association
DCEP (Direct Current Electrode Positive) Reverse Polarity
Heat input is less than spray transfer - resulting in less distortion - Used in all positions due to controlling the weld metal freeze
Spatter problems and poor weld appearance

14. What processes are constant current (CC) power sources designed to be used with?
Power source - wire feeder - welding gun - Spooled filler wire - Shielding gas - and a ground
These terms are quite restrictive and often technically incorrect
SMAW - GTAW
The resistace to electrical current flow increases with it. Causing the electrode to heat

15. Is the arc voltage for spray transfer higher or lower than that used for short circuit transfer?
Minimum distortion due to low heat input
Welding process that joins metals by heating them with an electric arc
Higher 26 to 35 arc volts
Guns

16. How many times per second does short circuiting take place?
20 to 200 times per second
Power source - wire feeder - welding gun - Spooled filler wire - Shielding gas - and a ground
Wire feed speed
Short- circuiting transfer - Globular transfer - Spray transfer

17. What output on the welding machine is used to rate the duty cycle?
Constant voltage (CV)
Reducing the gas source pressure to a constant working pressure
Minimum distortion due to low heat input
Minutes of elapsed time continually run (out of 10 minutes)

18. What is a typical flow rate of CO2 for short circuit transfer?
Welding process that joins metals by heating them with an electric arc
Constant- speed wire feeders and Voltage- sennsing wire feeders
National Electrical Manufactures Association
5.8 to 12.5 L/min

19. What does inductance control?
Welding Current - Filler wire diameter - arc length - type of shielding - position of the weld
DCEP (Direct Current Electrode Positive) Reverse Polarity
Puddle fluidity
The time rate of response for the current rise and fall

20. What type of power source is commonly used with a voltage sensing wire feeder?
Puddle fluidity
Duty cycle
15 feet (4.5 meters)
Constant current (CC)

21. What is the effect of too much slope?
Reducing the gas source pressure to a constant working pressure
The negative side of a welding unit
Insufficient current to melt the wire off cleanly
The resistace to electrical current flow increases with it. Causing the electrode to heat

22. Draw a typical volt/amp curve that would be found with a power source designed for SMAW or GTAW
DCEP (Direct Current Electrode Positive) Reverse Polarity
Welding Current - Filler wire diameter - arc length - type of shielding - position of the weld
If you dont know this check your phone
Duty cycle

23. What would be an indication that the drive roll pressure is adjusted correctly?
National Electrical Manufactures Association
Wire feeds smoothly (yet will slip should a problem occur in the gun)
Penetration and burn - off rate of the electrode
5.8 to 12.5 L/min

24. What does the wire feeder control?
These terms are quite restrictive and often technically incorrect
Heat input is less than spray transfer - resulting in less distortion - Used in all positions due to controlling the weld metal freeze
Speed of the feed motor and - starting / stopping electrode feed
Insufficient current to melt the wire off cleanly

25. What wire are knurled drive rolls most commonly used on?
Welding process that joins metals by heating them with an electric arc
AWS and CSA
Flux cored wires
15 feet (4.5 meters)

26. List several industries that would use GMAW
Pressure vessels and the piping industry
5.8 to 12.5 L/min
Pressure - The rate of flow of a shielding gas
Speed of the feed motor and - starting / stopping electrode feed

27. List the three methods of metal transfer with GMAW
Short- circuiting transfer - Globular transfer - Spray transfer
To prevent drawing of liquid CO2 (Carbon Dioxide)
Pressure - The rate of flow of a shielding gas
Pressure vessels and the piping industry

28. What is the reason glass 'tube' type flowmeters must have the tube mounted truly vertical?
(DCEP) Direct Current Electrode Positive or Reverse polarity
Welding process that joins metals by heating them with an electric arc
Electricaly operated valves that control the flow of shielding gas to the weld zone. The control switch located on the gun
...

29. Give a description of 'pinch effect'
Molten metal is separated from the end of the filler wire by a squeezing force created by a magnetic field
Constant current (CC)
20 to 200 times per second
Insufficient current to melt the wire off cleanly

30. What is a solenoid valve and what actuates it?
Wire feed speed
20 to 200 times per second
Electricaly operated valves that control the flow of shielding gas to the weld zone. The control switch located on the gun
Pressure vessels and the piping industry

31. A pull type drive system is usually used on what type of material?
SMAW - GTAW
Aluminum wire
20 to 200 times per second
Electricaly operated valves that control the flow of shielding gas to the weld zone. The control switch located on the gun

32. What is the recommended electrode stick- out for .035 solid wire?
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
Increasing inductance increases puddle fluidity - improves penatration - makes the bead flatter and smoother - and reduces spatter. To much inductance though will create erratic starts
20 to 200 times per second

33. In the GMAW process what does voltage control?
Puddle fluidity
Heat input is less than spray transfer - resulting in less distortion - Used in all positions due to controlling the weld metal freeze
The time rate of response for the current rise and fall
SMAW - GTAW

34. List 3 forms compressed gases may be supplied for welding
To limit the short circuiting current so that spatter is reduced
Increasing inductance increases puddle fluidity - improves penatration - makes the bead flatter and smoother - and reduces spatter. To much inductance though will create erratic starts
Compressed gas cylinder - Liquid filled cylinder - or a Liquid bulk system
When the filler wire is in direct contract with the base metal

35. What does the term GMAW identify?
Gas metal arc welding
Welding process that joins metals by heating them with an electric arc
Generally not as accurate
Gives arc voltage values to the control system of the feeder

36. What effect does increasing and decreasing the inductance have on the weld?
Gives arc voltage values to the control system of the feeder
Power source - wire feeder - welding gun - Spooled filler wire - Shielding gas - and a ground
Puddle fluidity
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. Give a brief description of the GMAW process
Welding process that joins metals by heating them with an electric arc
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
Spatter problems and poor weld appearance
20 to 200 times per second

38. What power sources are used with the GMAW Process?
15 feet (4.5 meters)
The resistace to electrical current flow increases with it. Causing the electrode to heat
Motor driven generators - Transformer rectifiers - and Inverter designs
Welding process that joins metals by heating them with an electric arc

39. What is the purpose of a regulator and what does it indicate on its gauges?
1/4 inch to 1/2 inch
Higher 26 to 35 arc volts
Welding Current - Filler wire diameter - arc length - type of shielding - position of the weld
Reducing the gas source pressure to a constant working pressure

40. What current and polarity is generally used with GMAW?
DCEP (Direct Current Electrode Positive) Reverse Polarity
If you dont know this check your phone
12 to 22 arc volts
Pressure vessels and the piping industry

41. How are GMAW guns rated?
Dry ice can form within the flow control openings and cause blockage of shielding gas
Penetration and burn - off rate of the electrode
To prevent leakage - Carbon Dioxide (CO2)
By there current carrying capacity

42. What 2 organizations designate specifications for GMAW wires?
Gas metal arc welding
Guns
20 to 200 times per second
AWS and CSA

43. What is the maximum distance that hard wire can be successfully pushed?
Short- circuiting transfer - Globular transfer - Spray transfer
Duty cycle
Gives arc voltage values to the control system of the feeder
15 feet (4.5 meters)

44. What is the purpose of the pick- up lead on a voltage sensing wire feeder?
The negative side of a welding unit
Duty cycle
Molten metal is separated from the end of the filler wire by a squeezing force created by a magnetic field
Gives arc voltage values to the control system of the feeder

45. Why is the term GMAW preferred over MIG or MAG?
These terms are quite restrictive and often technically incorrect
Gives arc voltage values to the control system of the feeder
Welding process that joins metals by heating them with an electric arc
Short- circuiting transfer - Globular transfer - Spray transfer

46. When using flat drive rolls with too much pressure on copper coated solid wires what problem could take place?
Wire feed speed
85%
12 to 22 arc volts
Cause flaking - which can clog the liner and contact tube

47. A machine with a 70% duty cycle can run at its max for 7 minutes with a cooling cycle of only _ minutes.
These terms are quite restrictive and often technically incorrect
3
Gives arc voltage values to the control system of the feeder
Guns

48. In the GMAW process what does amperage control?
20 to 200 times per second
Pressure - The rate of flow of a shielding gas
Voltage is the force that overcomes resistance to allow amperage flow
Penetration and burn - off rate of the electrode

49. What is the minimum % value of argon that must be present to use the spray transfer method of GMAW?
Constant voltage (CV)
Heat input is less than spray transfer - resulting in less distortion - Used in all positions due to controlling the weld metal freeze
85%
Wire feeds smoothly (yet will slip should a problem occur in the gun)

50. When is the metal transferred with short circuit transfer?
3
SMAW - GTAW
Dry ice can form within the flow control openings and cause blockage of shielding gas
When the filler wire is in direct contract with the base metal