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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?
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
85%
These terms are quite restrictive and often technically incorrect

2. Why must CO2 cylinders be used in the vertical position?
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
To prevent drawing of liquid CO2 (Carbon Dioxide)
SMAW - GTAW

3. Why is a line heater required when using GMAW?
20 to 200 times per second
5.8 to 12.5 L/min
Minimum distortion due to low heat input
Dry ice can form within the flow control openings and cause blockage of shielding gas

4. What type of power source is used with a constant speed wire feeder?
15 feet (4.5 meters)
SMAW - GTAW
Constant voltage (CV)
Minutes of elapsed time continually run (out of 10 minutes)

5. List 3 wire drive systems and give a short description of each
Compressed gas cylinder - Liquid filled cylinder - or a Liquid bulk system
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
85%
Minutes of elapsed time continually run (out of 10 minutes)

6. What does the abbreviation NEMA stand for?
National Electrical Manufactures Association
The time rate of response for the current rise and fall
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

7. What is the reason glass 'tube' type flowmeters must have the tube mounted truly vertical?
Penetration and burn - off rate of the electrode
AWS and CSA
To prevent leakage - Carbon Dioxide (CO2)
...

8. List the three methods of metal transfer with GMAW
Shielding the molten weld metal from atmospheric contamination
Insufficient current to melt the wire off cleanly
Minutes of elapsed time continually run (out of 10 minutes)
Short- circuiting transfer - Globular transfer - Spray transfer

9. What does voltage do in an electrical circuit?
Higher 26 to 35 arc volts
Electricaly operated valves that control the flow of shielding gas to the weld zone. The control switch located on the gun
Voltage is the force that overcomes resistance to allow amperage flow
12 to 22 arc volts

10. What controls amperage when using GMAW?
The negative side of a welding unit
Wire feed speed
Aluminum wire
Increasing inductance increases puddle fluidity - improves penatration - makes the bead flatter and smoother - and reduces spatter. To much inductance though will create erratic starts

11. What happens when the electrode extension is increased?
The resistace to electrical current flow increases with it. Causing the electrode to heat
To limit the short circuiting current so that spatter is reduced
15 feet (4.5 meters)
The Arc voltage

12. Draw a typical volt/amp curve that would be found with a power source designed for SMAW or 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
If you dont know this check your phone
Reducing the gas source pressure to a constant working pressure
Generally not as accurate

13. What is the disadvantage of the gauge preset type of regulator/flowmeter?
Guns
Generally not as accurate
Heat input is less than spray transfer - resulting in less distortion - Used in all positions due to controlling the weld metal freeze
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

14. What does inductance control?
The time rate of response for the current rise and fall
85%
The Arc voltage
Insufficient current to melt the wire off cleanly

15. In the GMAW process what does voltage control?
Constant voltage (CV)
Speed of the feed motor and - starting / stopping electrode feed
Pressure vessels and the piping industry
Puddle fluidity

16. What processes are constant current (CC) power sources designed to be used with?
To prevent drawing of liquid CO2 (Carbon Dioxide)
SMAW - GTAW
(DCEP) Direct Current Electrode Positive or Reverse polarity
Wire feeds smoothly (yet will slip should a problem occur in the gun)

17. Draw a typical volt amp curve for a machine that is designed for GMAW
15 feet (4.5 meters)
Minimum distortion due to low heat input
If you dont know this check your phone
Guns

18. What does a flowmeter do and what does it measure?
Welding Current - Filler wire diameter - arc length - type of shielding - position of the weld
(DCEP) Direct Current Electrode Positive or Reverse polarity
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

19. List the basic equipment requirements for the GMAW process
Electricaly operated valves that control the flow of shielding gas to the weld zone. The control switch located on the gun
Gas metal arc welding
Spatter problems and poor weld appearance
Power source - wire feeder - welding gun - Spooled filler wire - Shielding gas - and a ground

20. When using flat drive rolls with too much pressure on copper coated solid wires what problem could take place?
Motor driven generators - Transformer rectifiers - and Inverter designs
1/4 inch to 1/2 inch
20 to 200 times per second
Cause flaking - which can clog the liner and contact tube

21. What is the purpose of the pick- up lead on a voltage sensing wire feeder?
To limit the short circuiting current so that spatter is reduced
1/4 inch to 1/2 inch
Gives arc voltage values to the control system of the feeder
By there current carrying capacity

22. What power sources are used with the GMAW Process?
Motor driven generators - Transformer rectifiers - and Inverter designs
Constant- speed wire feeders and Voltage- sennsing wire feeders
Short- circuiting transfer - Globular transfer - Spray transfer
Wire feeds smoothly (yet will slip should a problem occur in the gun)

23. What output on the welding machine is used to rate the duty cycle?
Heat input is less than spray transfer - resulting in less distortion - Used in all positions due to controlling the weld metal freeze
Wire feeds smoothly (yet will slip should a problem occur in the gun)
Minutes of elapsed time continually run (out of 10 minutes)
Shielding the molten weld metal from atmospheric contamination

24. List several industries that would use GMAW
Pressure - The rate of flow of a shielding gas
Power source - wire feeder - welding gun - Spooled filler wire - Shielding gas - and a ground
Pressure vessels and the piping industry
Molten metal is separated from the end of the filler wire by a squeezing force created by a magnetic field

25. Why is a fiber washer required and what cylinder gas requires it?
To prevent leakage - Carbon Dioxide (CO2)
When the filler wire is in direct contract with the base metal
12 to 22 arc volts
Guns

26. What is the purpose of a regulator and what does it indicate on its gauges?
Wire feed speed
Reducing the gas source pressure to a constant working pressure
Power source - wire feeder - welding gun - Spooled filler wire - Shielding gas - and a ground
To prevent leakage - Carbon Dioxide (CO2)

27. With straight polarity where is 2/3 of the arc energy?
The negative side of a welding unit
Electricaly operated valves that control the flow of shielding gas to the weld zone. The control switch located on the gun
AWS and CSA
Flux cored wires

28. A pull type drive system is usually used on what type of material?
Heat input is less than spray transfer - resulting in less distortion - Used in all positions due to controlling the weld metal freeze
Speed of the feed motor and - starting / stopping electrode feed
Aluminum wire
Increasing inductance increases puddle fluidity - improves penatration - makes the bead flatter and smoother - and reduces spatter. To much inductance though will create erratic starts

29. Why is globular transfer generally avoided with GMAW?
Motor driven generators - Transformer rectifiers - and Inverter designs
These terms are quite restrictive and often technically incorrect
Spatter problems and poor weld appearance
Aluminum wire

30. Regulators control_____________ flowmeters SHOW____________.
Puddle fluidity
Aluminum wire
Pressure - The rate of flow of a shielding gas
The resistace to electrical current flow increases with it. Causing the electrode to heat

31. How are GMAW guns rated?
If you dont know this check your phone
By there current carrying capacity
Spatter problems and poor weld appearance
Reducing the gas source pressure to a constant working pressure

32. What current and polarity is generally used with GMAW?
Molten metal is separated from the end of the filler wire by a squeezing force created by a magnetic field
DCEP (Direct Current Electrode Positive) Reverse Polarity
To prevent drawing of liquid CO2 (Carbon Dioxide)
Short- circuiting transfer - Globular transfer - Spray transfer

33. A machine with a 70% duty cycle can run at its max for 7 minutes with a cooling cycle of only _ minutes.
Short- circuiting transfer - Globular transfer - Spray transfer
Insufficient current to melt the wire off cleanly
If you dont know this check your phone
3

34. What is the maximum distance that hard wire can be successfully pushed?
Electricaly operated valves that control the flow of shielding gas to the weld zone. The control switch located on the gun
15 feet (4.5 meters)
AWS and CSA
Gas metal arc welding

35. What 2 controls are found on a GMAW set- up?
...
Gives arc voltage values to the control system of the feeder
Higher 26 to 35 arc volts
Wire feed speed - Voltage control

36. What is another term for electrode holders for GMAW?
Penetration and burn - off rate of the electrode
20 to 200 times per second
Guns
(DCEP) Direct Current Electrode Positive or Reverse polarity

37. What type of power source is commonly used with a voltage sensing wire feeder?
Gas metal arc welding
Higher 26 to 35 arc volts
Constant current (CC)
The resistace to electrical current flow increases with it. Causing the electrode to heat

38. What does the term GMAW identify?
Gas metal arc welding
Welding process that joins metals by heating them with an electric arc
Short- circuiting transfer - Globular transfer - Spray transfer
SMAW - GTAW

39. What is the recommended electrode stick- out for .035 solid wire?
Shielding the molten weld metal from atmospheric contamination
Wire feed speed - Voltage control
1/4 inch to 1/2 inch
SMAW - GTAW

40. What is a typical flow rate of CO2 for short circuit transfer?
85%
5.8 to 12.5 L/min
Welding process that joins metals by heating them with an electric arc
Wire feed speed

41. Give a description of 'pinch effect'
20 to 200 times per second
Shielding the molten weld metal from atmospheric contamination
Molten metal is separated from the end of the filler wire by a squeezing force created by a magnetic field
Aluminum wire

42. What is the effect of too much slope?
...
Pressure vessels and the piping industry
Generally not as accurate
Insufficient current to melt the wire off cleanly

43. What is a solenoid valve and what actuates it?
Electricaly operated valves that control the flow of shielding gas to the weld zone. The control switch located on the gun
Motor driven generators - Transformer rectifiers - and Inverter designs
Power source - wire feeder - welding gun - Spooled filler wire - Shielding gas - and a ground
Short- circuiting transfer - Globular transfer - Spray transfer

44. What does the wire feeder control?
Motor driven generators - Transformer rectifiers - and Inverter designs
Compressed gas cylinder - Liquid filled cylinder - or a Liquid bulk system
Wire feed speed - Voltage control
Speed of the feed motor and - starting / stopping electrode feed

45. In the GMAW process what does amperage control?
Controls the rate of flow of a shielding gas to the gun nozzle
Guns
Penetration and burn - off rate of the electrode
Cause flaking - which can clog the liner and contact tube

46. What is the main purpose of 'slope'?
DCEP (Direct Current Electrode Positive) Reverse Polarity
To limit the short circuiting current so that spatter is reduced
To prevent drawing of liquid CO2 (Carbon Dioxide)
Gas metal arc welding

47. Give a brief description of the GMAW process
Constant current (CC)
Wire feed speed
If you dont know this check your phone
Welding process that joins metals by heating them with an electric arc

48. When is the metal transferred with short circuit transfer?
5.8 to 12.5 L/min
Constant voltage (CV)
V groove or U groove
When the filler wire is in direct contract with the base metal

49. What wire are knurled drive rolls most commonly used on?
Flux cored wires
Electricaly operated valves that control the flow of shielding gas to the weld zone. The control switch located on the gun
The time rate of response for the current rise and fall
Voltage is the force that overcomes resistance to allow amperage flow

50. List the factors that determine the mode of metal transfer
Duty cycle
Guns
Welding Current - Filler wire diameter - arc length - type of shielding - position of the weld
Shielding the molten weld metal from atmospheric contamination