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Gas Metal Arc Welding

Instructions:

Answer 50 questions in 15 minutes.
If you are not ready to take this test, you can study here.
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. Regulators control_____________ flowmeters SHOW____________.
AWS and CSA
Pressure - The rate of flow of a shielding gas
Insufficient current to melt the wire off cleanly
Power source - wire feeder - welding gun - Spooled filler wire - Shielding gas - and a ground

2. What is the effect of too much slope?
SMAW - GTAW
Constant voltage (CV)
Insufficient current to melt the wire off cleanly
Short- circuiting transfer - Globular transfer - Spray transfer

3. What does the abbreviation NEMA stand for?
85%
Shielding the molten weld metal from atmospheric contamination
Penetration and burn - off rate of the electrode
National Electrical Manufactures Association

4. What wire are knurled drive rolls most commonly used on?
Increasing inductance increases puddle fluidity - improves penatration - makes the bead flatter and smoother - and reduces spatter. To much inductance though will create erratic starts
Cause flaking - which can clog the liner and contact tube
Constant- speed wire feeders and Voltage- sennsing wire feeders
Flux cored wires

5. What is the disadvantage of the gauge preset type of regulator/flowmeter?
Welding Current - Filler wire diameter - arc length - type of shielding - position of the weld
1/4 inch to 1/2 inch
Generally not as accurate
Short- circuiting transfer - Globular transfer - Spray transfer

6. List the basic equipment requirements for the GMAW process
Power source - wire feeder - welding gun - Spooled filler wire - Shielding gas - and a ground
Gives arc voltage values to the control system of the feeder
Electricaly operated valves that control the flow of shielding gas to the weld zone. The control switch located on the gun
3

7. What is the required arc voltage used for short circuit transfer?
Wire feeds smoothly (yet will slip should a problem occur in the gun)
V groove or U groove
12 to 22 arc volts
Gives arc voltage values to the control system of the feeder

8. What 2 controls are found on a GMAW set- up?
Reducing the gas source pressure to a constant working pressure
These terms are quite restrictive and often technically incorrect
Wire feed speed - Voltage control
Pressure - The rate of flow of a shielding gas

9. What type of power source is commonly used with a voltage sensing wire feeder?
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
To prevent leakage - Carbon Dioxide (CO2)
Duty cycle
Constant current (CC)

10. What does a flowmeter do and what does it measure?
Duty cycle
Shielding the molten weld metal from atmospheric contamination
Reducing the gas source pressure to a constant working pressure
Controls the rate of flow of a shielding gas to the gun nozzle

11. What is the minimum % value of argon that must be present to use the spray transfer method of GMAW?
Voltage is the force that overcomes resistance to allow amperage flow
Molten metal is separated from the end of the filler wire by a squeezing force created by a magnetic field
Puddle fluidity
85%

12. When is the metal transferred with short circuit transfer?
Voltage is the force that overcomes resistance to allow amperage flow
Welding Current - Filler wire diameter - arc length - type of shielding - position of the weld
Heat input is less than spray transfer - resulting in less distortion - Used in all positions due to controlling the weld metal freeze
When the filler wire is in direct contract with the base metal

13. What is another term for electrode holders for GMAW?
Guns
Increasing inductance increases puddle fluidity - improves penatration - makes the bead flatter and smoother - and reduces spatter. To much inductance though will create erratic starts
Electricaly operated valves that control the flow of shielding gas to the weld zone. The control switch located on the gun
National Electrical Manufactures Association

14. What does the term GMAW identify?
Gas metal arc welding
Power source - wire feeder - welding gun - Spooled filler wire - Shielding gas - and a ground
Aluminum wire
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

15. In the GMAW process what does voltage control?
Reducing the gas source pressure to a constant working pressure
The resistace to electrical current flow increases with it. Causing the electrode to heat
Puddle fluidity
3

16. What is the reason glass 'tube' type flowmeters must have the tube mounted truly vertical?
Short- circuiting transfer - Globular transfer - Spray transfer
Welding process that joins metals by heating them with an electric arc
5.8 to 12.5 L/min
...

17. What effect does increasing and decreasing the inductance have on the weld?
DCEP (Direct Current Electrode Positive) Reverse Polarity
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
Voltage is the force that overcomes resistance to allow amperage flow

18. 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
Constant current (CC)
Short- circuiting transfer - Globular transfer - Spray transfer
To prevent drawing of liquid CO2 (Carbon Dioxide)

19. What 2 organizations designate specifications for GMAW wires?
Pressure - The rate of flow of a shielding gas
Electricaly operated valves that control the flow of shielding gas to the weld zone. The control switch located on the gun
Constant current (CC)
AWS and CSA

20. List the three methods of metal transfer with GMAW
V groove or U groove
AWS and CSA
Welding process that joins metals by heating them with an electric arc
Short- circuiting transfer - Globular transfer - Spray transfer

21. With straight polarity where is 2/3 of the arc energy?
To prevent drawing of liquid CO2 (Carbon Dioxide)
DCEP (Direct Current Electrode Positive) Reverse Polarity
The negative side of a welding unit
Heat input is less than spray transfer - resulting in less distortion - Used in all positions due to controlling the weld metal freeze

22. Give a brief description of the GMAW process
Penetration and burn - off rate of the electrode
Wire feeds smoothly (yet will slip should a problem occur in the gun)
Power source - wire feeder - welding gun - Spooled filler wire - Shielding gas - and a ground
Welding process that joins metals by heating them with an electric arc

23. Why is globular transfer generally avoided with GMAW?
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
Guns
Spatter problems and poor weld appearance
DCEP (Direct Current Electrode Positive) Reverse Polarity

24. What would be an indication that the drive roll pressure is adjusted correctly?
Increasing inductance increases puddle fluidity - improves penatration - makes the bead flatter and smoother - and reduces spatter. To much inductance though will create erratic starts
Gives arc voltage values to the control system of the feeder
Wire feeds smoothly (yet will slip should a problem occur in the gun)
Aluminum wire

25. Why is a line heater required when using GMAW?
Dry ice can form within the flow control openings and cause blockage of shielding gas
Aluminum wire
Constant current (CC)
Short- circuiting transfer - Globular transfer - Spray transfer

26. A pull type drive system is usually used on what type of material?
By there current carrying capacity
Insufficient current to melt the wire off cleanly
Dry ice can form within the flow control openings and cause blockage of shielding gas
Aluminum wire

27. How many times per second does short circuiting take place?
20 to 200 times per second
AWS and CSA
To limit the short circuiting current so that spatter is reduced
Constant voltage (CV)

28. Why must CO2 cylinders be used in the vertical position?
5.8 to 12.5 L/min
Constant- speed wire feeders and Voltage- sennsing wire feeders
Gives arc voltage values to the control system of the feeder
To prevent drawing of liquid CO2 (Carbon Dioxide)

29. What controls the wire speed on a voltage sensing wire feeder?
Shielding the molten weld metal from atmospheric contamination
Increasing inductance increases puddle fluidity - improves penatration - makes the bead flatter and smoother - and reduces spatter. To much inductance though will create erratic starts
Controls the rate of flow of a shielding gas to the gun nozzle
The Arc voltage

30. What are the 2 types of wire feeders available?
Puddle fluidity
Constant- speed wire feeders and Voltage- sennsing wire feeders
The negative side of a welding unit
1/4 inch to 1/2 inch

31. What is the key advantage of short circuiting transfer?
Short- circuiting transfer - Globular transfer - Spray transfer
Welding process that joins metals by heating them with an electric arc
1/4 inch to 1/2 inch
Minimum distortion due to low heat input

32. What is the preferred drive roll design for solid wires?
Shielding the molten weld metal from atmospheric contamination
V groove or U groove
Wire feeds smoothly (yet will slip should a problem occur in the gun)
85%

33. When using flat drive rolls with too much pressure on copper coated solid wires what problem could take place?
The time rate of response for the current rise and fall
Cause flaking - which can clog the liner and contact tube
Generally not as accurate
AWS and CSA

34. List 3 wire drive systems and give a short description of each
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
If you dont know this check your phone
20 to 200 times per second
To prevent leakage - Carbon Dioxide (CO2)

35. What is the purpose of the shielding gas used in GMAW?
Shielding the molten weld metal from atmospheric contamination
When the filler wire is in direct contract with the base metal
Reducing the gas source pressure to a constant working pressure
Speed of the feed motor and - starting / stopping electrode feed

36. What is the recommended electrode stick- out for .035 solid wire?
Electricaly operated valves that control the flow of shielding gas to the weld zone. The control switch located on the gun
Duty cycle
These terms are quite restrictive and often technically incorrect
1/4 inch to 1/2 inch

37. What is a solenoid valve and what actuates it?
Duty cycle
The resistace to electrical current flow increases with it. Causing the electrode to heat
Electricaly operated valves that control the flow of shielding gas to the weld zone. The control switch located on the gun
These terms are quite restrictive and often technically incorrect

38. What controls amperage when using GMAW?
When the filler wire is in direct contract with the base metal
Gas metal arc welding
20 to 200 times per second
Wire feed speed

39. Draw a typical volt/amp curve that would be found with a power source designed for SMAW or GTAW
Guns
Speed of the feed motor and - starting / stopping electrode feed
Voltage is the force that overcomes resistance to allow amperage flow
If you dont know this check your phone

40. Why is a fiber washer required and what cylinder gas requires it?
By there current carrying capacity
Gas metal arc welding
To prevent leakage - Carbon Dioxide (CO2)
To limit the short circuiting current so that spatter is reduced

41. A machine with a 70% duty cycle can run at its max for 7 minutes with a cooling cycle of only _ 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
The Arc voltage
3
Minutes of elapsed time continually run (out of 10 minutes)

42. Is the arc voltage for spray transfer higher or lower than that used for short circuit transfer?
15 feet (4.5 meters)
Higher 26 to 35 arc volts
If you dont know this check your phone
Puddle fluidity

43. What does voltage do in an electrical circuit?
Speed of the feed motor and - starting / stopping electrode feed
Molten metal is separated from the end of the filler wire by a squeezing force created by a magnetic field
Voltage is the force that overcomes resistance to allow amperage flow
Gas metal arc welding

44. What processes are constant current (CC) power sources designed to be used with?
SMAW - GTAW
12 to 22 arc volts
Generally not as accurate
The Arc voltage

45. What happens when the electrode extension is increased?
Duty cycle
Puddle fluidity
The resistace to electrical current flow increases with it. Causing the electrode to heat
Pressure - The rate of flow of a shielding gas

46. What is a typical flow rate of CO2 for short circuit transfer?
1/4 inch to 1/2 inch
85%
Pressure - The rate of flow of a shielding gas
5.8 to 12.5 L/min

47. What type of power source is used with a constant speed wire feeder?
To limit the short circuiting current so that spatter is reduced
Pressure - The rate of flow of a shielding gas
Constant voltage (CV)
Flux cored wires

48. What is the purpose of the pick- up lead on a voltage sensing wire feeder?
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
Wire feed speed - Voltage control
These terms are quite restrictive and often technically incorrect
Gives arc voltage values to the control system of the feeder

49. List 3 forms compressed gases may be supplied for welding
Welding Current - Filler wire diameter - arc length - type of shielding - position of the weld
...
National Electrical Manufactures Association
Compressed gas cylinder - Liquid filled cylinder - or a Liquid bulk system

50. A 10 minute cycle of welding time vs cooling time a given machine can handle.
Cause flaking - which can clog the liner and contact tube
Minimum distortion due to low heat input
Duty cycle
85%