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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. What does inductance control?
Voltage is the force that overcomes resistance to allow amperage flow
5.8 to 12.5 L/min
The time rate of response for the current rise and fall
(DCEP) Direct Current Electrode Positive or Reverse polarity

2. What power sources are used with the GMAW Process?
To prevent drawing of liquid CO2 (Carbon Dioxide)
12 to 22 arc volts
Motor driven generators - Transformer rectifiers - and Inverter designs
Voltage is the force that overcomes resistance to allow amperage flow

3. When using flat drive rolls with too much pressure on copper coated solid wires what problem could take place?
Wire feed speed - Voltage control
Duty cycle
Cause flaking - which can clog the liner and contact tube
15 feet (4.5 meters)

4. A pull type drive system is usually used on what type of material?
Speed of the feed motor and - starting / stopping electrode feed
Minutes of elapsed time continually run (out of 10 minutes)
Aluminum wire
Dry ice can form within the flow control openings and cause blockage of shielding gas

5. What is the minimum % value of argon that must be present to use the spray transfer method of GMAW?
DCEP (Direct Current Electrode Positive) Reverse Polarity
Voltage is the force that overcomes resistance to allow amperage flow
85%
1/4 inch to 1/2 inch

6. What would be an indication that the drive roll pressure is adjusted correctly?
To prevent drawing of liquid CO2 (Carbon Dioxide)
Wire feeds smoothly (yet will slip should a problem occur in the gun)
The Arc voltage
Short- circuiting transfer - Globular transfer - Spray transfer

7. Why is a line heater required when using GMAW?
Dry ice can form within the flow control openings and cause blockage of shielding gas
85%
Short- circuiting transfer - Globular transfer - Spray transfer
Duty cycle

8. What is the purpose of the shielding gas used in GMAW?
...
Controls the rate of flow of a shielding gas to the gun nozzle
Shielding the molten weld metal from atmospheric contamination
5.8 to 12.5 L/min

9. What 2 controls are found on a GMAW set- up?
To prevent drawing of liquid CO2 (Carbon Dioxide)
Wire feed speed - Voltage control
Reducing the gas source pressure to a constant working pressure
Motor driven generators - Transformer rectifiers - and Inverter designs

10. What type of power source is commonly used with a voltage sensing wire feeder?
Power source - wire feeder - welding gun - Spooled filler wire - Shielding gas - and a ground
Pressure vessels and the piping industry
Welding process that joins metals by heating them with an electric arc
Constant current (CC)

11. What type of power source is used with a constant speed wire feeder?
Shielding the molten weld metal from atmospheric contamination
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
Dry ice can form within the flow control openings and cause blockage of shielding gas
Constant voltage (CV)

12. What is a solenoid valve and what actuates it?
15 feet (4.5 meters)
Gas metal arc welding
Generally not as accurate
Electricaly operated valves that control the flow of shielding gas to the weld zone. The control switch located on the gun

13. When is the metal transferred with short circuit transfer?
DCEP (Direct Current Electrode Positive) Reverse Polarity
SMAW - GTAW
When the filler wire is in direct contract with the base metal
Spatter problems and poor weld appearance

14. What controls amperage when using GMAW?
Minimum distortion due to low heat input
Wire feed speed
Guns
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. What happens when the electrode extension is increased?
By there current carrying capacity
The resistace to electrical current flow increases with it. Causing the electrode to heat
When the filler wire is in direct contract with the base metal
3

16. List the basic equipment requirements for the GMAW process
The resistace to electrical current flow increases with it. Causing the electrode to heat
The negative side of a welding unit
Power source - wire feeder - welding gun - Spooled filler wire - Shielding gas - and a ground
Increasing inductance increases puddle fluidity - improves penatration - makes the bead flatter and smoother - and reduces spatter. To much inductance though will create erratic starts

17. Regulators control_____________ flowmeters SHOW____________.
Pressure - The rate of flow of a shielding gas
To limit the short circuiting current so that spatter is reduced
The Arc voltage
15 feet (4.5 meters)

18. What does the abbreviation NEMA stand for?
The negative side of a welding unit
Minimum distortion due to low heat input
15 feet (4.5 meters)
National Electrical Manufactures Association

19. What is the maximum distance that hard wire can be successfully pushed?
To limit the short circuiting current so that spatter is reduced
By there current carrying capacity
Generally not as accurate
15 feet (4.5 meters)

20. 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
...
Controls the rate of flow of a shielding gas to the gun nozzle
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

21. What controls the wire speed on a voltage sensing wire feeder?
The Arc voltage
3
Controls the rate of flow of a shielding gas to the gun nozzle
Voltage is the force that overcomes resistance to allow amperage flow

22. What is the main purpose of 'slope'?
20 to 200 times per second
Compressed gas cylinder - Liquid filled cylinder - or a Liquid bulk system
By there current carrying capacity
To limit the short circuiting current so that spatter is reduced

23. With straight polarity where is 2/3 of the arc energy?
Gas metal arc welding
Insufficient current to melt the wire off cleanly
National Electrical Manufactures Association
The negative side of a welding unit

24. List the factors that determine the mode of metal transfer
Wire feeds smoothly (yet will slip should a problem occur in the gun)
Welding Current - Filler wire diameter - arc length - type of shielding - position of the weld
Minutes of elapsed time continually run (out of 10 minutes)
When the filler wire is in direct contract with the base metal

25. In the GMAW process what does amperage control?
15 feet (4.5 meters)
(DCEP) Direct Current Electrode Positive or Reverse polarity
Penetration and burn - off rate of the electrode
By there current carrying capacity

26. A machine with a 70% duty cycle can run at its max for 7 minutes with a cooling cycle of only _ minutes.
3
Short- circuiting transfer - Globular transfer - Spray transfer
Motor driven generators - Transformer rectifiers - and Inverter designs
National Electrical Manufactures Association

27. List 3 forms compressed gases may be supplied for welding
Minutes of elapsed time continually run (out of 10 minutes)
Compressed gas cylinder - Liquid filled cylinder - or a Liquid bulk system
Short- circuiting transfer - Globular transfer - Spray transfer
If you dont know this check your phone

28. What current and polarity is generally used with GMAW?
Power source - wire feeder - welding gun - Spooled filler wire - Shielding gas - and a ground
Speed of the feed motor and - starting / stopping electrode feed
By there current carrying capacity
DCEP (Direct Current Electrode Positive) Reverse Polarity

29. Why must CO2 cylinders be used in the vertical position?
Speed of the feed motor and - starting / stopping electrode feed
To prevent drawing of liquid CO2 (Carbon Dioxide)
If you dont know this check your phone
Minutes of elapsed time continually run (out of 10 minutes)

30. What output on the welding machine is used to rate the duty cycle?
Penetration and burn - off rate of the electrode
V groove or U groove
Minutes of elapsed time continually run (out of 10 minutes)
Reducing the gas source pressure to a constant working pressure

31. What is another term for electrode holders for GMAW?
Guns
Higher 26 to 35 arc volts
Flux cored wires
...

32. 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
Wire feed speed
Spatter problems and poor weld appearance
12 to 22 arc volts

33. What is the reason glass 'tube' type flowmeters must have the tube mounted truly vertical?
Cause flaking - which can clog the liner and contact tube
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)

34. What is the preferred drive roll design for solid wires?
V groove or U groove
Puddle fluidity
Dry ice can form within the flow control openings and cause blockage of shielding gas
Wire feed speed

35. In the GMAW process what does voltage control?
Minutes of elapsed time continually run (out of 10 minutes)
Generally not as accurate
Puddle fluidity
Pressure - The rate of flow of a shielding gas

36. Draw a typical volt/amp curve that would be found with a power source designed for SMAW or GTAW
If you dont know this check your phone
12 to 22 arc volts
Penetration and burn - off rate of the electrode
Electricaly operated valves that control the flow of shielding gas to the weld zone. The control switch located on the gun

37. 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
85%
Minimum distortion due to low heat input
Pressure - The rate of flow of a shielding gas

38. What is the disadvantage of the gauge preset type of regulator/flowmeter?
Heat input is less than spray transfer - resulting in less distortion - Used in all positions due to controlling the weld metal freeze
15 feet (4.5 meters)
The time rate of response for the current rise and fall
Generally not as accurate

39. What does the wire feeder control?
Welding process that joins metals by heating them with an electric arc
Penetration and burn - off rate of the electrode
Controls the rate of flow of a shielding gas to the gun nozzle
Speed of the feed motor and - starting / stopping electrode feed

40. Draw a typical volt amp curve for a machine that is designed for GMAW
Guns
12 to 22 arc volts
If you dont know this check your phone
Minutes of elapsed time continually run (out of 10 minutes)

41. How are GMAW guns rated?
(DCEP) Direct Current Electrode Positive or Reverse polarity
Guns
To prevent leakage - Carbon Dioxide (CO2)
By there current carrying capacity

42. What are the 2 types of wire feeders available?
Constant- speed wire feeders and Voltage- sennsing wire feeders
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
20 to 200 times per second
Wire feed speed

43. Why is globular transfer generally avoided with GMAW?
AWS and CSA
Spatter problems and poor weld appearance
(DCEP) Direct Current Electrode Positive or Reverse polarity
Shielding the molten weld metal from atmospheric contamination

44. What is the effect of too much slope?
Gas metal arc welding
Reducing the gas source pressure to a constant working pressure
Insufficient current to melt the wire off cleanly
SMAW - GTAW

45. Is the arc voltage for spray transfer higher or lower than that used for short circuit transfer?
1/4 inch to 1/2 inch
12 to 22 arc volts
85%
Higher 26 to 35 arc volts

46. What 2 organizations designate specifications for GMAW wires?
Pressure - The rate of flow of a shielding gas
AWS and CSA
If you dont know this check your phone
20 to 200 times per second

47. What is the key advantage of short circuiting transfer?
Minimum distortion due to low heat input
Insufficient current to melt the wire off cleanly
(DCEP) Direct Current Electrode Positive or Reverse polarity
To prevent leakage - Carbon Dioxide (CO2)

48. List the three methods of metal transfer with GMAW
Flux cored wires
(DCEP) Direct Current Electrode Positive or Reverse polarity
Heat input is less than spray transfer - resulting in less distortion - Used in all positions due to controlling the weld metal freeze
Short- circuiting transfer - Globular transfer - Spray transfer

49. What is the required arc voltage used for short circuit transfer?
Constant voltage (CV)
Dry ice can form within the flow control openings and cause blockage of shielding gas
12 to 22 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

50. List several industries that would use GMAW
Welding Current - Filler wire diameter - arc length - type of shielding - position of the weld
Pressure vessels and the piping industry
15 feet (4.5 meters)
Minutes of elapsed time continually run (out of 10 minutes)