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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 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)
15 feet (4.5 meters)
3
National Electrical Manufactures Association

2. List 3 wire drive systems and give a short description of each
National Electrical Manufactures Association
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
When the filler wire is in direct contract with the base metal
Compressed gas cylinder - Liquid filled cylinder - or a Liquid bulk system

3. What is the disadvantage of the gauge preset type of regulator/flowmeter?
Constant current (CC)
5.8 to 12.5 L/min
AWS and CSA
Generally not as accurate

4. List the basic equipment requirements for the GMAW process
Power source - wire feeder - welding gun - Spooled filler wire - Shielding gas - and a ground
(DCEP) Direct Current Electrode Positive or Reverse polarity
Higher 26 to 35 arc volts
Short- circuiting transfer - Globular transfer - Spray transfer

5. What does the abbreviation NEMA stand for?
Reducing the gas source pressure to a constant working pressure
Welding Current - Filler wire diameter - arc length - type of shielding - position of the weld
Cause flaking - which can clog the liner and contact tube
National Electrical Manufactures Association

6. List 3 forms compressed gases may be supplied for welding
Heat input is less than spray transfer - resulting in less distortion - Used in all positions due to controlling the weld metal freeze
Compressed gas cylinder - Liquid filled cylinder - or a Liquid bulk system
Cause flaking - which can clog the liner and contact tube
Gives arc voltage values to the control system of the feeder

7. When using flat drive rolls with too much pressure on copper coated solid wires what problem could take place?
When the filler wire is in direct contract with the base metal
Wire feeds smoothly (yet will slip should a problem occur in the gun)
...
Cause flaking - which can clog the liner and contact tube

8. With straight polarity where is 2/3 of the arc energy?
The negative side of a welding unit
Duty cycle
Welding Current - Filler wire diameter - arc length - type of shielding - position of the weld
15 feet (4.5 meters)

9. List several industries that would use GMAW
Flux cored wires
To limit the short circuiting current so that spatter is reduced
Pressure vessels and the piping industry
Constant- speed wire feeders and Voltage- sennsing wire feeders

10. 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
Constant voltage (CV)
Shielding the molten weld metal from atmospheric contamination
3

11. What is the purpose of the shielding gas used in GMAW?
Shielding the molten weld metal from atmospheric contamination
Increasing inductance increases puddle fluidity - improves penatration - makes the bead flatter and smoother - and reduces spatter. To much inductance though will create erratic starts
Voltage is the force that overcomes resistance to allow amperage flow
SMAW - GTAW

12. What is the required arc voltage used for short circuit transfer?
V groove or U groove
Penetration and burn - off rate of the electrode
Generally not as accurate
12 to 22 arc volts

13. What is a typical flow rate of CO2 for short circuit transfer?
The resistace to electrical current flow increases with it. Causing the electrode to heat
AWS and CSA
5.8 to 12.5 L/min
Gives arc voltage values to the control system of the feeder

14. What is the effect of too much slope?
Insufficient current to melt the wire off cleanly
...
The Arc voltage
Generally not as accurate

15. What does voltage do in an electrical circuit?
Voltage is the force that overcomes resistance to allow amperage flow
By there current carrying capacity
DCEP (Direct Current Electrode Positive) Reverse Polarity
Puddle fluidity

16. What is an advantage of pulsed arc transfer with GMAW?
Wire feeds smoothly (yet will slip should a problem occur in the gun)
Pressure - The rate of flow of a 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
Heat input is less than spray transfer - resulting in less distortion - Used in all positions due to controlling the weld metal freeze

17. What processes are constant current (CC) power sources designed to be used with?
SMAW - GTAW
To prevent drawing of liquid CO2 (Carbon Dioxide)
The time rate of response for the current rise and fall
AWS and CSA

18. What is the key advantage of short circuiting transfer?
Motor driven generators - Transformer rectifiers - and Inverter designs
V groove or U groove
The time rate of response for the current rise and fall
Minimum distortion due to low heat input

19. What is the main purpose of 'slope'?
To limit the short circuiting current so that spatter is reduced
Insufficient current to melt the wire off cleanly
AWS and CSA
Wire feeds smoothly (yet will slip should a problem occur in the gun)

20. 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
Gives arc voltage values to the control system of the feeder
Generally not as accurate
By there current carrying capacity

21. What does the wire feeder control?
Electricaly operated valves that control the flow of shielding gas to the weld zone. The control switch located on the gun
AWS and CSA
To prevent leakage - Carbon Dioxide (CO2)
Speed of the feed motor and - starting / stopping electrode feed

22. What does a flowmeter do and what does it measure?
To limit the short circuiting current so that spatter is reduced
Controls the rate of flow of a shielding gas to the gun nozzle
Speed of the feed motor and - starting / stopping electrode feed
To prevent drawing of liquid CO2 (Carbon Dioxide)

23. 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
Minutes of elapsed time continually run (out of 10 minutes)
Penetration and burn - off rate of the electrode
Generally not as accurate

24. Give a brief description of the GMAW process
Welding process that joins metals by heating them with an electric arc
Speed of the feed motor and - starting / stopping electrode feed
Puddle fluidity
Wire feed speed - Voltage control

25. What 2 organizations designate specifications for GMAW wires?
Wire feed speed
AWS and CSA
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)

26. 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
Minimum distortion due to low heat input
Insufficient current to melt the wire off cleanly
85%

27. Is the arc voltage for spray transfer higher or lower than that used for short circuit transfer?
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
Higher 26 to 35 arc volts
Gas metal arc welding

28. What is the maximum distance that hard wire can be successfully pushed?
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
Shielding the molten weld metal from atmospheric contamination
Pressure - The rate of flow of a shielding gas
15 feet (4.5 meters)

29. In the GMAW process what does voltage control?
Electricaly operated valves that control the flow of shielding gas to the weld zone. The control switch located on the gun
Speed of the feed motor and - starting / stopping electrode feed
Puddle fluidity
If you dont know this check your phone

30. In the GMAW process what does amperage control?
Cause flaking - which can clog the liner and contact tube
Penetration and burn - off rate of the electrode
When the filler wire is in direct contract with the base metal
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. When is the metal transferred with short circuit transfer?
The Arc voltage
Shielding the molten weld metal from atmospheric contamination
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

32. Why is globular transfer generally avoided with GMAW?
20 to 200 times per second
Constant- speed wire feeders and Voltage- sennsing wire feeders
Spatter problems and poor weld appearance
National Electrical Manufactures Association

33. What current and polarity is generally used with GMAW?
If you dont know this check your phone
Spatter problems and poor weld appearance
Speed of the feed motor and - starting / stopping electrode feed
DCEP (Direct Current Electrode Positive) Reverse Polarity

34. A machine with a 70% duty cycle can run at its max for 7 minutes with a cooling cycle of only _ minutes.
3
Welding process that joins metals by heating them with an electric arc
85%
Motor driven generators - Transformer rectifiers - and Inverter designs

35. A 10 minute cycle of welding time vs cooling time a given machine can handle.
These terms are quite restrictive and often technically incorrect
Insufficient current to melt the wire off cleanly
By there current carrying capacity
Duty cycle

36. What is the minimum % value of argon that must be present to use the spray transfer method of GMAW?
To prevent drawing of liquid CO2 (Carbon Dioxide)
Constant current (CC)
85%
When the filler wire is in direct contract with the base metal

37. What is the reason glass 'tube' type flowmeters must have the tube mounted truly vertical?
...
Power source - wire feeder - welding gun - Spooled filler wire - Shielding gas - and a ground
Aluminum wire
5.8 to 12.5 L/min

38. Why is a line heater required when using GMAW?
Gas metal arc welding
Constant- speed wire feeders and Voltage- sennsing wire feeders
Dry ice can form within the flow control openings and cause blockage of shielding gas
V groove or U groove

39. Why must CO2 cylinders be used in the vertical position?
Heat input is less than spray transfer - resulting in less distortion - Used in all positions due to controlling the weld metal freeze
Minimum distortion due to low heat input
To prevent drawing of liquid CO2 (Carbon Dioxide)
1/4 inch to 1/2 inch

40. What type of power source is commonly used with a voltage sensing wire feeder?
To limit the short circuiting current so that spatter is reduced
Constant current (CC)
Gas metal arc welding
Puddle fluidity

41. What does the term GMAW identify?
Gas metal arc welding
Constant- speed wire feeders and Voltage- sennsing wire feeders
Wire feeds smoothly (yet will slip should a problem occur in the gun)
The resistace to electrical current flow increases with it. Causing the electrode to heat

42. Give a description of 'pinch effect'
SMAW - GTAW
Molten metal is separated from the end of the filler wire by a squeezing force created by a magnetic field
These terms are quite restrictive and often technically incorrect
20 to 200 times per second

43. What 2 controls are found on a GMAW set- up?
Pressure - The rate of flow of a shielding gas
The time rate of response for the current rise and fall
Shielding the molten weld metal from atmospheric contamination
Wire feed speed - Voltage control

44. What is the recommended electrode stick- out for .035 solid wire?
Welding Current - Filler wire diameter - arc length - type of shielding - position of the weld
These terms are quite restrictive and often technically incorrect
Dry ice can form within the flow control openings and cause blockage of shielding gas
1/4 inch to 1/2 inch

45. List the three methods of metal transfer with GMAW
SMAW - GTAW
Short- circuiting transfer - Globular transfer - Spray transfer
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

46. Why is a fiber washer required and what cylinder gas requires it?
To prevent leakage - Carbon Dioxide (CO2)
Minimum distortion due to low heat input
Wire feed speed
Flux cored wires

47. List the factors that determine the mode of metal transfer
Gas metal arc welding
Welding Current - Filler wire diameter - arc length - type of shielding - position of the weld
The negative side of a welding unit
Minimum distortion due to low heat input

48. What happens when the electrode extension is increased?
Minutes of elapsed time continually run (out of 10 minutes)
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
The time rate of response for the current rise and fall

49. A pull type drive system is usually used on what type of material?
SMAW - GTAW
Aluminum wire
Motor driven generators - Transformer rectifiers - and Inverter designs
V groove or U groove

50. What controls amperage when using GMAW?
SMAW - GTAW
Wire feed speed
15 feet (4.5 meters)
Constant- speed wire feeders and Voltage- sennsing wire feeders