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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 does the term GMAW identify?
Generally not as accurate
3
Gas metal arc welding
Wire feeds smoothly (yet will slip should a problem occur in the gun)

2. What is the main purpose of 'slope'?
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
12 to 22 arc volts
Reducing the gas source pressure to a constant working pressure
To limit the short circuiting current so that spatter is reduced

3. Draw a typical volt amp curve for a machine that is designed for GMAW
Duty cycle
5.8 to 12.5 L/min
Short- circuiting transfer - Globular transfer - Spray transfer
If you dont know this check your phone

4. Draw a typical volt/amp curve that would be found with a power source designed for SMAW or GTAW
When the filler wire is in direct contract with the base metal
To prevent drawing of liquid CO2 (Carbon Dioxide)
If you dont know this check your phone
Spatter problems and poor weld appearance

5. List the three methods of metal transfer with GMAW
Short- circuiting transfer - Globular transfer - Spray transfer
Constant voltage (CV)
The time rate of response for the current rise and fall
Shielding the molten weld metal from atmospheric contamination

6. What is the reason glass 'tube' type flowmeters must have the tube mounted truly vertical?
The resistace to electrical current flow increases with it. Causing the electrode to heat
...
85%
Controls the rate of flow of a shielding gas to the gun nozzle

7. What is the key advantage of short circuiting transfer?
20 to 200 times per second
Minimum distortion due to low heat input
To limit the short circuiting current so that spatter is reduced
Welding Current - Filler wire diameter - arc length - type of shielding - position of the weld

8. What is the recommended electrode stick- out for .035 solid wire?
1/4 inch to 1/2 inch
Gas metal arc welding
Wire feed speed
3

9. A pull type drive system is usually used on what type of material?
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
Aluminum wire
National Electrical Manufactures Association

10. Regulators control_____________ flowmeters SHOW____________.
Pressure - The rate of flow of a shielding gas
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
Wire feed speed

11. What happens when the electrode extension is increased?
To prevent leakage - Carbon Dioxide (CO2)
The resistace to electrical current flow increases with it. Causing the electrode to heat
Minutes of elapsed time continually run (out of 10 minutes)
...

12. What effect does increasing and decreasing the inductance have on the weld?
National Electrical Manufactures Association
Increasing inductance increases puddle fluidity - improves penatration - makes the bead flatter and smoother - and reduces spatter. To much inductance though will create erratic starts
These terms are quite restrictive and often technically incorrect
To prevent leakage - Carbon Dioxide (CO2)

13. Why is a fiber washer required and what cylinder gas requires it?
When the filler wire is in direct contract with the base metal
To prevent leakage - Carbon Dioxide (CO2)
Pressure vessels and the piping industry
Minutes of elapsed time continually run (out of 10 minutes)

14. 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
1/4 inch to 1/2 inch
85%
Increasing inductance increases puddle fluidity - improves penatration - makes the bead flatter and smoother - and reduces spatter. To much inductance though will create erratic starts

15. List the basic equipment requirements for the GMAW process
These terms are quite restrictive and often technically incorrect
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
If you dont know this check your phone

16. What does the abbreviation NEMA stand for?
National Electrical Manufactures Association
To limit the short circuiting current so that spatter is reduced
15 feet (4.5 meters)
Constant current (CC)

17. When using flat drive rolls with too much pressure on copper coated solid wires what problem could take place?
Cause flaking - which can clog the liner and contact tube
Pressure - The rate of flow of a shielding gas
DCEP (Direct Current Electrode Positive) Reverse Polarity
Compressed gas cylinder - Liquid filled cylinder - or a Liquid bulk system

18. Give a brief description of the GMAW process
Compressed gas cylinder - Liquid filled cylinder - or a Liquid bulk system
The time rate of response for the current rise and fall
Welding process that joins metals by heating them with an electric arc
Wire feed speed

19. Why must CO2 cylinders be used in the vertical position?
Wire feeds smoothly (yet will slip should a problem occur in the gun)
Puddle fluidity
To prevent drawing of liquid CO2 (Carbon Dioxide)
Constant- speed wire feeders and Voltage- sennsing wire feeders

20. Is the arc voltage for spray transfer higher or lower than that used for short circuit transfer?
Higher 26 to 35 arc volts
Reducing the gas source pressure to a constant working pressure
V groove or U groove
Pressure vessels and the piping industry

21. List several industries that would use GMAW
Dry ice can form within the flow control openings and cause blockage of shielding gas
Flux cored wires
Pressure vessels and the piping industry
Welding process that joins metals by heating them with an electric arc

22. How many times per second does short circuiting take place?
Aluminum wire
Compressed gas cylinder - Liquid filled cylinder - or a Liquid bulk system
Penetration and burn - off rate of the electrode
20 to 200 times per second

23. What is the required arc voltage used for short circuit transfer?
The time rate of response for the current rise and fall
3
12 to 22 arc volts
Pressure - The rate of flow of a shielding gas

24. What type of power source is used with a constant speed 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
Constant voltage (CV)
Electricaly operated valves that control the flow of shielding gas to the weld zone. The control switch located on the gun
Flux cored wires

25. What 2 organizations designate specifications for GMAW wires?
Gives arc voltage values to the control system of the 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
These terms are quite restrictive and often technically incorrect
AWS and CSA

26. What type of power source is commonly used with a voltage sensing wire feeder?
Spatter problems and poor weld appearance
Constant current (CC)
Constant voltage (CV)
Puddle fluidity

27. In the GMAW process what does amperage control?
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
Penetration and burn - off rate of the electrode
Welding process that joins metals by heating them with an electric arc

28. What does voltage do in an electrical circuit?
Pressure vessels and the piping industry
When the filler wire is in direct contract with the base metal
These terms are quite restrictive and often technically incorrect
Voltage is the force that overcomes resistance to allow amperage flow

29. Why is globular transfer generally avoided with GMAW?
To limit the short circuiting current so that spatter is reduced
Shielding the molten weld metal from atmospheric contamination
(DCEP) Direct Current Electrode Positive or Reverse polarity
Spatter problems and poor weld appearance

30. What does inductance control?
The Arc voltage
Cause flaking - which can clog the liner and contact tube
The time rate of response for the current rise and fall
If you dont know this check your phone

31. What are the 2 types of wire feeders available?
Welding Current - Filler wire diameter - arc length - type of shielding - position of the weld
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
Short- circuiting transfer - Globular transfer - Spray transfer
Constant- speed wire feeders and Voltage- sennsing wire feeders

32. What wire are knurled drive rolls most commonly used on?
Duty cycle
Spatter problems and poor weld appearance
Penetration and burn - off rate of the electrode
Flux cored wires

33. What is a solenoid valve and what actuates it?
Heat input is less than spray transfer - resulting in less distortion - Used in all positions due to controlling the weld metal freeze
Flux cored wires
The Arc voltage
Electricaly operated valves that control the flow of shielding gas to the weld zone. The control switch located on the gun

34. What power sources are used with the GMAW Process?
...
12 to 22 arc volts
Wire feed speed
Motor driven generators - Transformer rectifiers - and Inverter designs

35. What does the wire feeder control?
Speed of the feed motor and - starting / stopping electrode feed
Constant- speed wire feeders and Voltage- sennsing wire feeders
...
1/4 inch to 1/2 inch

36. What output on the welding machine is used to rate the duty cycle?
Motor driven generators - Transformer rectifiers - and Inverter designs
Minutes of elapsed time continually run (out of 10 minutes)
Dry ice can form within the flow control openings and cause blockage of shielding gas
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

37. What is the purpose of the shielding gas used in GMAW?
Duty cycle
Controls the rate of flow of a shielding gas to the gun nozzle
Reducing the gas source pressure to a constant working pressure
Shielding the molten weld metal from atmospheric contamination

38. What is a typical flow rate of CO2 for short circuit transfer?
3
Constant- speed wire feeders and Voltage- sennsing wire feeders
5.8 to 12.5 L/min
By there current carrying capacity

39. What is the maximum distance that hard wire can be successfully pushed?
If you dont know this check your phone
3
Insufficient current to melt the wire off cleanly
15 feet (4.5 meters)

40. List 3 wire drive systems and give a short description of each
Penetration and burn - off rate of the electrode
...
To limit the short circuiting current so that spatter is reduced
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

41. A machine with a 70% duty cycle can run at its max for 7 minutes with a cooling cycle of only _ minutes.
3
Wire feeds smoothly (yet will slip should a problem occur in the gun)
National Electrical Manufactures Association
Wire feed speed

42. What controls amperage when using GMAW?
Constant voltage (CV)
Wire feed speed
Heat input is less than spray transfer - resulting in less distortion - Used in all positions due to controlling the weld metal freeze
Pressure - The rate of flow of a shielding gas

43. Why is the term GMAW preferred over MIG or MAG?
Constant- speed wire feeders and Voltage- sennsing wire feeders
Higher 26 to 35 arc volts
These terms are quite restrictive and often technically incorrect
Controls the rate of flow of a shielding gas to the gun nozzle

44. What is the preferred drive roll design for solid wires?
To prevent leakage - Carbon Dioxide (CO2)
To prevent drawing of liquid CO2 (Carbon Dioxide)
Compressed gas cylinder - Liquid filled cylinder - or a Liquid bulk system
V groove or U groove

45. What is the effect of too much slope?
By there current carrying capacity
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 feeds smoothly (yet will slip should a problem occur in the gun)
Insufficient current to melt the wire off cleanly

46. 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)
To limit the short circuiting current so that spatter is reduced
Gives arc voltage values to the control system of the feeder
DCEP (Direct Current Electrode Positive) Reverse Polarity

47. What processes are constant current (CC) power sources designed to be used with?
Speed of the feed motor and - starting / stopping electrode feed
SMAW - GTAW
Wire feed speed
Higher 26 to 35 arc volts

48. In the GMAW process what does voltage control?
The time rate of response for the current rise and fall
Shielding the molten weld metal from atmospheric contamination
The negative side of a welding unit
Puddle fluidity

49. What current and polarity is generally used with GMAW?
DCEP (Direct Current Electrode Positive) Reverse Polarity
Gas metal arc welding
Compressed gas cylinder - Liquid filled cylinder - or a Liquid bulk system
Spatter problems and poor weld appearance

50. What does a flowmeter do and what does it measure?
Heat input is less than spray transfer - resulting in less distortion - Used in all positions due to controlling the weld metal freeze
Aluminum wire
(DCEP) Direct Current Electrode Positive or Reverse polarity
Controls the rate of flow of a shielding gas to the gun nozzle