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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 minimum % value of argon that must be present to use the spray transfer method of GMAW?
Controls the rate of flow of a shielding gas to the gun nozzle
85%
12 to 22 arc volts
Wire feed speed

2. 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
Controls the rate of flow of a shielding gas to the gun nozzle
3
National Electrical Manufactures Association

3. Give a brief description of the GMAW process
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
Welding process that joins metals by heating them with an electric arc
V groove or U groove
Constant voltage (CV)

4. What is the maximum distance that hard wire can be successfully pushed?
85%
AWS and CSA
Shielding the molten weld metal from atmospheric contamination
15 feet (4.5 meters)

5. With straight polarity where is 2/3 of the arc energy?
The negative side of a welding unit
Gives arc voltage values to the control system of the feeder
The Arc voltage
Welding process that joins metals by heating them with an electric arc

6. What does inductance control?
5.8 to 12.5 L/min
The time rate of response for the current rise and fall
These terms are quite restrictive and often technically incorrect
Shielding the molten weld metal from atmospheric contamination

7. What effect does increasing and decreasing the inductance have on the weld?
Power source - wire feeder - welding gun - Spooled filler wire - Shielding gas - and a ground
Minimum distortion due to low heat input
Dry ice can form within the flow control openings and cause blockage of shielding gas
Increasing inductance increases puddle fluidity - improves penatration - makes the bead flatter and smoother - and reduces spatter. To much inductance though will create erratic starts

8. Is the arc voltage for spray transfer higher or lower than that used for short circuit transfer?
Penetration and burn - off rate of the electrode
DCEP (Direct Current Electrode Positive) Reverse Polarity
5.8 to 12.5 L/min
Higher 26 to 35 arc volts

9. In the GMAW process what does voltage control?
Compressed gas cylinder - Liquid filled cylinder - or a Liquid bulk system
Puddle fluidity
20 to 200 times per second
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

10. What type of power source is used with a constant speed wire feeder?
Spatter problems and poor weld appearance
Constant voltage (CV)
National Electrical Manufactures Association
Power source - wire feeder - welding gun - Spooled filler wire - Shielding gas - and a ground

11. 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
National Electrical Manufactures Association
Motor driven generators - Transformer rectifiers - and Inverter designs
Wire feed speed

12. What is the reason glass 'tube' type flowmeters must have the tube mounted truly vertical?
...
Pressure vessels and the piping industry
20 to 200 times per second
DCEP (Direct Current Electrode Positive) Reverse Polarity

13. Why is a line heater required when using GMAW?
Controls the rate of flow of a shielding gas to the gun nozzle
If you dont know this check your phone
Dry ice can form within the flow control openings and cause blockage of shielding gas
SMAW - GTAW

14. When is the metal transferred with short circuit transfer?
3
Shielding the molten weld metal from atmospheric contamination
Gives arc voltage values to the control system of the feeder
When the filler wire is in direct contract with the base metal

15. What 2 organizations designate specifications for GMAW wires?
The time rate of response for the current rise and fall
AWS and CSA
Shielding the molten weld metal from atmospheric contamination
To prevent drawing of liquid CO2 (Carbon Dioxide)

16. How many times per second does short circuiting take place?
20 to 200 times per second
Penetration and burn - off rate of the electrode
The Arc voltage
5.8 to 12.5 L/min

17. What is the preferred drive roll design for solid wires?
V groove or U groove
Shielding the molten weld metal from atmospheric contamination
Gives arc voltage values to the control system of the feeder
Wire feed speed - Voltage control

18. Regulators control_____________ flowmeters SHOW____________.
Constant voltage (CV)
V groove or U groove
Pressure - The rate of flow of a shielding gas
Dry ice can form within the flow control openings and cause blockage of shielding gas

19. List the factors that determine the mode of metal transfer
Power source - wire feeder - welding gun - Spooled filler wire - Shielding gas - and a ground
12 to 22 arc volts
Welding Current - Filler wire diameter - arc length - type of shielding - position of the weld
Minutes of elapsed time continually run (out of 10 minutes)

20. What wire are knurled drive rolls most commonly used on?
85%
Flux cored wires
...
To prevent drawing of liquid CO2 (Carbon Dioxide)

21. What is the disadvantage of the gauge preset type of regulator/flowmeter?
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
Constant voltage (CV)
Spatter problems and poor weld appearance

22. What is the required arc voltage used for short circuit transfer?
Speed of the feed motor and - starting / stopping electrode feed
Gives arc voltage values to the control system of the feeder
To prevent leakage - Carbon Dioxide (CO2)
12 to 22 arc volts

23. What is another term for electrode holders for GMAW?
Wire feeds smoothly (yet will slip should a problem occur in the gun)
Guns
Speed of the feed motor and - starting / stopping electrode feed
Pressure vessels and the piping industry

24. What are the 2 types of wire feeders available?
Higher 26 to 35 arc volts
Minutes of elapsed time continually run (out of 10 minutes)
The time rate of response for the current rise and fall
Constant- speed wire feeders and Voltage- sennsing wire feeders

25. What is the purpose of a regulator and what does it indicate on its gauges?
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
SMAW - GTAW
Reducing the gas source pressure to a constant working pressure

26. List 3 wire drive systems and give a short description of each
85%
Generally not as accurate
To prevent drawing of liquid CO2 (Carbon Dioxide)
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

27. What is the main purpose of 'slope'?
Reducing the gas source pressure to a constant working pressure
Wire feeds smoothly (yet will slip should a problem occur in the gun)
To limit the short circuiting current so that spatter is reduced
Wire feed speed - Voltage control

28. Draw a typical volt/amp curve that would be found with a power source designed for SMAW or GTAW
The time rate of response for the current rise and fall
V groove or U groove
If you dont know this check your phone
Compressed gas cylinder - Liquid filled cylinder - or a Liquid bulk system

29. A pull type drive system is usually used on what type of material?
Aluminum wire
Insufficient current to melt the wire off cleanly
...
V groove or U groove

30. List the three methods of metal transfer with GMAW
Reducing the gas source pressure to a constant working pressure
Motor driven generators - Transformer rectifiers - and Inverter designs
Short- circuiting transfer - Globular transfer - Spray transfer
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

31. What does the term GMAW identify?
Gas metal arc welding
12 to 22 arc volts
Speed of the feed motor and - starting / stopping electrode feed
The negative side of a welding unit

32. When using flat drive rolls with too much pressure on copper coated solid wires what problem could take place?
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 prevent drawing of liquid CO2 (Carbon Dioxide)
Minimum distortion due to low heat input
Cause flaking - which can clog the liner and contact tube

33. Why is the term GMAW preferred over MIG or MAG?
The Arc voltage
Minimum distortion due to low heat input
To prevent drawing of liquid CO2 (Carbon Dioxide)
These terms are quite restrictive and often technically incorrect

34. What controls the wire speed on a voltage sensing wire feeder?
By there current carrying capacity
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
The Arc voltage

35. What does the abbreviation NEMA stand for?
5.8 to 12.5 L/min
AWS and CSA
3
National Electrical Manufactures Association

36. What 2 controls are found on a GMAW set- up?
Penetration and burn - off rate of the electrode
Wire feed speed - Voltage control
To prevent drawing of liquid CO2 (Carbon Dioxide)
5.8 to 12.5 L/min

37. What is the key advantage of short circuiting transfer?
When the filler wire is in direct contract with the base metal
Constant current (CC)
Minimum distortion due to low heat input
20 to 200 times per second

38. List the basic equipment requirements for the GMAW process
...
Minutes of elapsed time continually run (out of 10 minutes)
Generally not as accurate
Power source - wire feeder - welding gun - Spooled filler wire - Shielding gas - and a ground

39. A 10 minute cycle of welding time vs cooling time a given machine can handle.
(DCEP) Direct Current Electrode Positive or Reverse polarity
Minutes of elapsed time continually run (out of 10 minutes)
Gives arc voltage values to the control system of the feeder
Duty cycle

40. Draw a typical volt amp curve for a machine that is designed for GMAW
Spatter problems and poor weld appearance
Aluminum wire
If you dont know this check your phone
The resistace to electrical current flow increases with it. Causing the electrode to heat

41. What current and polarity is generally used with GMAW?
Penetration and burn - off rate of the electrode
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
DCEP (Direct Current Electrode Positive) Reverse Polarity
1/4 inch to 1/2 inch

42. What would be an indication that the drive roll pressure is adjusted correctly?
Wire feeds smoothly (yet will slip should a problem occur in the gun)
Insufficient current to melt the wire off cleanly
Minimum distortion due to low heat input
Dry ice can form within the flow control openings and cause blockage of shielding gas

43. What is a solenoid valve and what actuates it?
Voltage is the force that overcomes resistance to allow amperage flow
Higher 26 to 35 arc volts
Constant- speed wire feeders and Voltage- sennsing wire feeders
Electricaly operated valves that control the flow of shielding gas to the weld zone. The control switch located on the gun

44. What is an advantage of pulsed arc transfer with GMAW?
Speed of the feed motor and - starting / stopping electrode feed
Heat input is less than spray transfer - resulting in less distortion - Used in all positions due to controlling the weld metal freeze
DCEP (Direct Current Electrode Positive) Reverse Polarity
If you dont know this check your phone

45. What happens when the electrode extension is increased?
Shielding the molten weld metal from atmospheric contamination
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
The resistace to electrical current flow increases with it. Causing the electrode to heat

46. How are GMAW guns rated?
By there current carrying capacity
To prevent drawing of liquid CO2 (Carbon Dioxide)
Generally not as accurate
...

47. What is the recommended electrode stick- out for .035 solid wire?
(DCEP) Direct Current Electrode Positive or Reverse polarity
20 to 200 times per second
National Electrical Manufactures Association
1/4 inch to 1/2 inch

48. What is a typical flow rate of CO2 for short circuit transfer?
These terms are quite restrictive and often technically incorrect
National Electrical Manufactures Association
5.8 to 12.5 L/min
Pressure - The rate of flow of a shielding gas

49. Why must CO2 cylinders be used in the vertical position?
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
Puddle fluidity
5.8 to 12.5 L/min
To prevent drawing of liquid CO2 (Carbon Dioxide)

50. Why is globular transfer generally avoided with GMAW?
SMAW - GTAW
Power source - wire feeder - welding gun - Spooled filler wire - Shielding gas - and a ground
Spatter problems and poor weld appearance
V groove or U groove