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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. 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
Gas metal arc welding
Controls the rate of flow of a shielding gas to the gun nozzle

2. What is another term for electrode holders for GMAW?
These terms are quite restrictive and often technically incorrect
Welding Current - Filler wire diameter - arc length - type of shielding - position of the weld
The time rate of response for the current rise and fall
Guns

3. What term is used to describe when the workpiece is hooked to the negative pole on the power source?
12 to 22 arc volts
When the filler wire is in direct contract with the base metal
To prevent drawing of liquid CO2 (Carbon Dioxide)
(DCEP) Direct Current Electrode Positive or Reverse polarity

4. What is the recommended electrode stick- out for .035 solid wire?
Insufficient current to melt the wire off cleanly
Electricaly operated valves that control the flow of shielding gas to the weld zone. The control switch located on the gun
Minutes of elapsed time continually run (out of 10 minutes)
1/4 inch to 1/2 inch

5. What does a flowmeter do and what does it measure?
Motor driven generators - Transformer rectifiers - and Inverter designs
By there current carrying capacity
Controls the rate of flow of a shielding gas to the gun nozzle
The time rate of response for the current rise and fall

6. What controls amperage when using GMAW?
Spatter problems and poor weld appearance
AWS and CSA
Wire feed speed
Aluminum wire

7. What does the abbreviation NEMA stand for?
SMAW - GTAW
Generally not as accurate
Spatter problems and poor weld appearance
National Electrical Manufactures Association

8. Regulators control_____________ flowmeters SHOW____________.
15 feet (4.5 meters)
Pressure - The rate of flow of a shielding gas
Spatter problems and poor weld appearance
AWS and CSA

9. A machine with a 70% duty cycle can run at its max for 7 minutes with a cooling cycle of only _ minutes.
Constant- speed wire feeders and Voltage- sennsing wire feeders
Spatter problems and poor weld appearance
Voltage is the force that overcomes resistance to allow amperage flow
3

10. What does voltage do in an electrical circuit?
Gas metal arc welding
Voltage is the force that overcomes resistance to allow amperage flow
DCEP (Direct Current Electrode Positive) Reverse Polarity
Constant voltage (CV)

11. What is the reason glass 'tube' type flowmeters must have the tube mounted truly vertical?
Wire feed speed - Voltage control
20 to 200 times per second
Wire feeds smoothly (yet will slip should a problem occur in the gun)
...

12. Is the arc voltage for spray transfer higher or lower than that used for short circuit transfer?
Controls the rate of flow of a shielding gas to the gun nozzle
Electricaly operated valves that control the flow of shielding gas to the weld zone. The control switch located on the gun
Welding process that joins metals by heating them with an electric arc
Higher 26 to 35 arc volts

13. What controls the wire speed on a voltage sensing wire feeder?
National Electrical Manufactures Association
These terms are quite restrictive and often technically incorrect
The Arc voltage
Shielding the molten weld metal from atmospheric contamination

14. When using flat drive rolls with too much pressure on copper coated solid wires what problem could take place?
Speed of the feed motor and - starting / stopping electrode feed
Constant current (CC)
Puddle fluidity
Cause flaking - which can clog the liner and contact tube

15. What happens when the electrode extension is increased?
To prevent drawing of liquid CO2 (Carbon Dioxide)
Minutes of elapsed time continually run (out of 10 minutes)
The resistace to electrical current flow increases with it. Causing the electrode to heat
Reducing the gas source pressure to a constant working pressure

16. Draw a typical volt amp curve for a machine that is designed for GMAW
Compressed gas cylinder - Liquid filled cylinder - or a Liquid bulk system
Aluminum wire
If you dont know this check your phone
5.8 to 12.5 L/min

17. What is a typical flow rate of CO2 for short circuit transfer?
Minimum distortion due to low heat input
5.8 to 12.5 L/min
Constant- speed wire feeders and Voltage- sennsing wire feeders
Guns

18. What power sources are used with the GMAW Process?
Motor driven generators - Transformer rectifiers - and Inverter designs
The Arc voltage
SMAW - GTAW
These terms are quite restrictive and often technically incorrect

19. In the GMAW process what does amperage control?
85%
Penetration and burn - off rate of the electrode
Minutes of elapsed time continually run (out of 10 minutes)
Compressed gas cylinder - Liquid filled cylinder - or a Liquid bulk system

20. Draw a typical volt/amp curve that would be found with a power source designed for SMAW or GTAW
Guns
Heat input is less than spray transfer - resulting in less distortion - Used in all positions due to controlling the weld metal freeze
Welding Current - Filler wire diameter - arc length - type of shielding - position of the weld
If you dont know this check your phone

21. List the basic equipment requirements for the GMAW process
Power source - wire feeder - welding gun - Spooled filler wire - Shielding gas - and a ground
1/4 inch to 1/2 inch
Higher 26 to 35 arc volts
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

22. What output on the welding machine is used to rate the duty cycle?
Compressed gas cylinder - Liquid filled cylinder - or a Liquid bulk system
To prevent leakage - Carbon Dioxide (CO2)
5.8 to 12.5 L/min
Minutes of elapsed time continually run (out of 10 minutes)

23. Give a description of 'pinch effect'
The resistace to electrical current flow increases with it. Causing the electrode to heat
Welding Current - Filler wire diameter - arc length - type of shielding - position of the weld
Molten metal is separated from the end of the filler wire by a squeezing force created by a magnetic field
Wire feeds smoothly (yet will slip should a problem occur in the gun)

24. What is the purpose of the shielding gas used in GMAW?
Power source - wire feeder - welding gun - Spooled filler wire - Shielding gas - and a ground
Wire feed speed
Constant current (CC)
Shielding the molten weld metal from atmospheric contamination

25. What would be an indication that the drive roll pressure is adjusted correctly?
Motor driven generators - Transformer rectifiers - and Inverter designs
Wire feeds smoothly (yet will slip should a problem occur in the gun)
Minutes of elapsed time continually run (out of 10 minutes)
20 to 200 times per second

26. What is the disadvantage of the gauge preset type of regulator/flowmeter?
Controls the rate of flow of a shielding gas to the gun nozzle
The Arc voltage
If you dont know this check your phone
Generally not as accurate

27. What processes are constant current (CC) power sources designed to be used with?
(DCEP) Direct Current Electrode Positive or 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
Pressure vessels and the piping industry
SMAW - GTAW

28. A 10 minute cycle of welding time vs cooling time a given machine can handle.
Duty cycle
Voltage is the force that overcomes resistance to allow amperage flow
...
Gas metal arc welding

29. What type of power source is commonly used with a voltage sensing wire feeder?
When the filler wire is in direct contract with the base metal
Spatter problems and poor weld appearance
Constant current (CC)
Voltage is the force that overcomes resistance to allow amperage flow

30. With straight polarity where is 2/3 of the arc energy?
The negative side of a welding unit
20 to 200 times per second
To limit the short circuiting current so that spatter is reduced
Puddle fluidity

31. What is the preferred drive roll design for solid wires?
Motor driven generators - Transformer rectifiers - and Inverter designs
V groove or U groove
By there current carrying capacity
Flux cored wires

32. What is the key advantage of short circuiting transfer?
Controls the rate of flow of a shielding gas to the gun nozzle
Minimum distortion due to low heat input
If you dont know this check your phone
5.8 to 12.5 L/min

33. How are GMAW guns rated?
Reducing the gas source pressure to a constant working pressure
By there current carrying capacity
To prevent leakage - Carbon Dioxide (CO2)
The negative side of a welding unit

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
Increasing inductance increases puddle fluidity - improves penatration - makes the bead flatter and smoother - and reduces spatter. To much inductance though will create erratic starts
3
Molten metal is separated from the end of the filler wire by a squeezing force created by a magnetic field

35. In the GMAW process what does voltage control?
Wire feed speed
5.8 to 12.5 L/min
Puddle fluidity
Heat input is less than spray transfer - resulting in less distortion - Used in all positions due to controlling the weld metal freeze

36. Give a brief description of the GMAW process
Welding process that joins metals by heating them with an electric arc
Pressure - The rate of flow of a shielding gas
The Arc voltage
5.8 to 12.5 L/min

37. What is the required arc voltage used for short circuit transfer?
12 to 22 arc volts
DCEP (Direct Current Electrode Positive) Reverse Polarity
(DCEP) Direct Current Electrode Positive or Reverse polarity
1/4 inch to 1/2 inch

38. What does the wire feeder control?
Wire feed speed
Speed of the feed motor and - starting / stopping electrode feed
(DCEP) Direct Current Electrode Positive or Reverse polarity
Aluminum wire

39. What 2 controls are found on a GMAW set- up?
These terms are quite restrictive and often technically incorrect
Wire feed speed - Voltage control
Compressed gas cylinder - Liquid filled cylinder - or a Liquid bulk system
Generally not as accurate

40. What is the purpose of the pick- up lead on a voltage sensing wire feeder?
Gives arc voltage values to the control system of the feeder
To prevent leakage - Carbon Dioxide (CO2)
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

41. List the three methods of metal transfer with GMAW
Controls the rate of flow of a shielding gas to the gun nozzle
Duty cycle
Short- circuiting transfer - Globular transfer - Spray transfer
If you dont know this check your phone

42. What current and polarity is generally used with GMAW?
Spatter problems and poor weld appearance
To prevent drawing of liquid CO2 (Carbon Dioxide)
National Electrical Manufactures Association
DCEP (Direct Current Electrode Positive) Reverse Polarity

43. List 3 forms compressed gases may be supplied for welding
Cause flaking - which can clog the liner and contact tube
...
Insufficient current to melt the wire off cleanly
Compressed gas cylinder - Liquid filled cylinder - or a Liquid bulk system

44. What 2 organizations designate specifications for GMAW wires?
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
AWS and CSA
National Electrical Manufactures Association

45. Why must CO2 cylinders be used in the vertical position?
V groove or U groove
85%
(DCEP) Direct Current Electrode Positive or Reverse polarity
To prevent drawing of liquid CO2 (Carbon Dioxide)

46. What is the main purpose of 'slope'?
Gives arc voltage values to the control system of the feeder
Minutes of elapsed time continually run (out of 10 minutes)
To limit the short circuiting current so that spatter is reduced
When the filler wire is in direct contract with the base metal

47. What is the maximum distance that hard wire can be successfully pushed?
Pressure - The rate of flow of a shielding gas
12 to 22 arc volts
15 feet (4.5 meters)
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

48. What does inductance control?
The time rate of response for the current rise and fall
DCEP (Direct Current Electrode Positive) Reverse Polarity
Insufficient current to melt the wire off cleanly
Dry ice can form within the flow control openings and cause blockage of shielding gas

49. A pull type drive system is usually used on what type of material?
Motor driven generators - Transformer rectifiers - and Inverter designs
Penetration and burn - off rate of the electrode
...
Aluminum wire

50. What effect does increasing and decreasing the inductance have on the weld?
Molten metal is separated from the end of the filler wire by a squeezing force created by a magnetic field
SMAW - GTAW
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