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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. List the factors that determine the mode of metal transfer
The time rate of response for the current rise and fall
15 feet (4.5 meters)
Wire feed speed
Welding Current - Filler wire diameter - arc length - type of shielding - position of the weld

2. What is the minimum % value of argon that must be present to use the spray transfer method of GMAW?
Puddle fluidity
Short- circuiting transfer - Globular transfer - Spray transfer
Motor driven generators - Transformer rectifiers - and Inverter designs
85%

3. What processes are constant current (CC) power sources designed to be used with?
Welding Current - Filler wire diameter - arc length - type of shielding - position of the weld
Voltage is the force that overcomes resistance to allow amperage flow
SMAW - GTAW
DCEP (Direct Current Electrode Positive) Reverse Polarity

4. A machine with a 70% duty cycle can run at its max for 7 minutes with a cooling cycle of only _ minutes.
3
DCEP (Direct Current Electrode Positive) Reverse Polarity
Motor driven generators - Transformer rectifiers - and Inverter designs
National Electrical Manufactures Association

5. List 3 wire drive systems and give a short description of each
Welding process that joins metals by heating them with an electric arc
Generally not as accurate
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

6. What does the wire feeder control?
V groove or U groove
Speed of the feed motor and - starting / stopping electrode feed
Duty cycle
Molten metal is separated from the end of the filler wire by a squeezing force created by a magnetic field

7. What is the maximum distance that hard wire can be successfully pushed?
AWS and CSA
15 feet (4.5 meters)
The resistace to electrical current flow increases with it. Causing the electrode to heat
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. 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
Flux cored wires
Motor driven generators - Transformer rectifiers - and Inverter designs
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

9. What does the term GMAW identify?
Welding Current - Filler wire diameter - arc length - type of shielding - position of the weld
Welding process that joins metals by heating them with an electric arc
Minutes of elapsed time continually run (out of 10 minutes)
Gas metal arc welding

10. List several industries that would use GMAW
Short- circuiting transfer - Globular transfer - Spray transfer
The time rate of response for the current rise and fall
Pressure vessels and the piping industry
Welding process that joins metals by heating them with an electric arc

11. What is the purpose of a regulator and what does it indicate on its gauges?
Penetration and burn - off rate of the electrode
Constant voltage (CV)
Reducing the gas source pressure to a constant working pressure
Welding process that joins metals by heating them with an electric arc

12. What is the recommended electrode stick- out for .035 solid wire?
1/4 inch to 1/2 inch
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
Wire feeds smoothly (yet will slip should a problem occur in the gun)

13. What is the reason glass 'tube' type flowmeters must have the tube mounted truly vertical?
These terms are quite restrictive and often technically incorrect
Wire feed speed
...
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. A pull type drive system is usually used on what type of material?
Minutes of elapsed time continually run (out of 10 minutes)
15 feet (4.5 meters)
Aluminum wire
Higher 26 to 35 arc volts

15. What output on the welding machine is used to rate the duty cycle?
Minutes of elapsed time continually run (out of 10 minutes)
Constant current (CC)
The negative side of a welding unit
To limit the short circuiting current so that spatter is reduced

16. What type of power source is commonly used with a voltage sensing wire feeder?
Constant current (CC)
Shielding the molten weld metal from atmospheric contamination
Insufficient current to melt the wire off cleanly
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. What 2 controls are found on a GMAW set- up?
Higher 26 to 35 arc volts
National Electrical Manufactures Association
Constant- speed wire feeders and Voltage- sennsing wire feeders
Wire feed speed - Voltage control

18. Why must CO2 cylinders be used in the vertical position?
20 to 200 times per second
3
To prevent drawing of liquid CO2 (Carbon Dioxide)
...

19. When using flat drive rolls with too much pressure on copper coated solid wires what problem could take place?
Puddle fluidity
To prevent leakage - Carbon Dioxide (CO2)
Wire feed speed - Voltage control
Cause flaking - which can clog the liner and contact tube

20. What current and polarity is generally used with GMAW?
To limit the short circuiting current so that spatter is reduced
These terms are quite restrictive and often technically incorrect
Welding process that joins metals by heating them with an electric arc
DCEP (Direct Current Electrode Positive) Reverse Polarity

21. What controls amperage when using GMAW?
Constant current (CC)
Cause flaking - which can clog the liner and contact tube
Wire feed speed
Pressure vessels and the piping industry

22. List 3 forms compressed gases may be supplied for welding
National Electrical Manufactures Association
Pressure vessels and the piping industry
The negative side of a welding unit
Compressed gas cylinder - Liquid filled cylinder - or a Liquid bulk system

23. How many times per second does short circuiting take place?
20 to 200 times per second
By there current carrying capacity
To prevent leakage - Carbon Dioxide (CO2)
The time rate of response for the current rise and fall

24. What is a solenoid valve and what actuates it?
Cause flaking - which can clog the liner and contact tube
85%
Wire feed speed - Voltage control
Electricaly operated valves that control the flow of shielding gas to the weld zone. The control switch located on the gun

25. In the GMAW process what does amperage control?
Penetration and burn - off rate of the electrode
SMAW - GTAW
AWS and CSA
15 feet (4.5 meters)

26. What is another term for electrode holders for GMAW?
National Electrical Manufactures Association
Guns
Increasing inductance increases puddle fluidity - improves penatration - makes the bead flatter and smoother - and reduces spatter. To much inductance though will create erratic starts
By there current carrying capacity

27. Give a description of 'pinch effect'
Voltage is the force that overcomes resistance to allow amperage flow
Wire feed speed - Voltage control
Molten metal is separated from the end of the filler wire by a squeezing force created by a magnetic field
15 feet (4.5 meters)

28. Draw a typical volt amp curve for a machine that is designed for GMAW
If you dont know this check your phone
The negative side of a welding unit
Gives arc voltage values to the control system of the feeder
Constant current (CC)

29. What is a typical flow rate of CO2 for short circuit transfer?
15 feet (4.5 meters)
5.8 to 12.5 L/min
Controls the rate of flow of a shielding gas to the gun nozzle
Guns

30. What is the disadvantage of the gauge preset type of regulator/flowmeter?
Electricaly operated valves that control the flow of shielding gas to the weld zone. The control switch located on the gun
Controls the rate of flow of a shielding gas to the gun nozzle
Generally not as accurate
Puddle fluidity

31. What is the main purpose of 'slope'?
Wire feed speed - Voltage control
5.8 to 12.5 L/min
To limit the short circuiting current so that spatter is reduced
1/4 inch to 1/2 inch

32. What does inductance control?
National Electrical Manufactures Association
V groove or U groove
The time rate of response for the current rise and fall
Welding process that joins metals by heating them with an electric arc

33. What 2 organizations designate specifications for GMAW wires?
DCEP (Direct Current Electrode Positive) Reverse Polarity
AWS and CSA
1/4 inch to 1/2 inch
Shielding the molten weld metal from atmospheric contamination

34. What is the purpose of the shielding gas used in GMAW?
Aluminum wire
Compressed gas cylinder - Liquid filled cylinder - or a Liquid bulk system
Shielding the molten weld metal from atmospheric contamination
Gives arc voltage values to the control system of the feeder

35. What type of power source is used with a constant speed wire feeder?
National Electrical Manufactures Association
These terms are quite restrictive and often technically incorrect
Constant voltage (CV)
Minutes of elapsed time continually run (out of 10 minutes)

36. What effect does increasing and decreasing the inductance have on the weld?
V groove or U groove
Pressure vessels and the piping industry
Pressure - The rate of flow of a 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

37. What does a flowmeter do and what does it measure?
Cause flaking - which can clog the liner and contact tube
Controls the rate of flow of a shielding gas to the gun nozzle
Flux cored wires
Reducing the gas source pressure to a constant working pressure

38. Why is the term GMAW preferred over MIG or MAG?
Welding process that joins metals by heating them with an electric arc
Minutes of elapsed time continually run (out of 10 minutes)
These terms are quite restrictive and often technically incorrect
Constant current (CC)

39. Draw a typical volt/amp curve that would be found with a power source designed for SMAW or GTAW
Guns
Gives arc voltage values to the control system of the feeder
Constant current (CC)
If you dont know this check your phone

40. What is the effect of too much slope?
Constant voltage (CV)
Insufficient current to melt the wire off cleanly
Penetration and burn - off rate of the electrode
Guns

41. What is the key advantage of short circuiting transfer?
Gives arc voltage values to the control system of the feeder
Molten metal is separated from the end of the filler wire by a squeezing force created by a magnetic field
Minimum distortion due to low heat input
15 feet (4.5 meters)

42. What would be an indication that the drive roll pressure is adjusted correctly?
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)
Wire feed speed - Voltage control
Dry ice can form within the flow control openings and cause blockage of shielding gas

43. What are the 2 types of wire feeders available?
To prevent drawing of liquid CO2 (Carbon Dioxide)
Constant- speed wire feeders and Voltage- sennsing wire feeders
DCEP (Direct Current Electrode Positive) Reverse Polarity
Pressure - The rate of flow of a shielding gas

44. A 10 minute cycle of welding time vs cooling time a given machine can handle.
Duty cycle
The Arc voltage
Dry ice can form within the flow control openings and cause blockage of shielding gas
20 to 200 times per second

45. What power sources are used with the GMAW Process?
Wire feed speed - Voltage control
SMAW - GTAW
Constant current (CC)
Motor driven generators - Transformer rectifiers - and Inverter designs

46. When is the metal transferred with short circuit transfer?
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
To limit the short circuiting current so that spatter is reduced
When the filler wire is in direct contract with the base metal

47. What does voltage do in an electrical circuit?
Voltage is the force that overcomes resistance to allow amperage flow
Pressure vessels and the piping industry
Insufficient current to melt the wire off cleanly
Reducing the gas source pressure to a constant working pressure

48. What is an advantage of pulsed arc transfer with GMAW?
Penetration and burn - off rate of the electrode
DCEP (Direct Current Electrode Positive) Reverse Polarity
Heat input is less than spray transfer - resulting in less distortion - Used in all positions due to controlling the weld metal freeze
The time rate of response for the current rise and fall

49. Why is globular transfer generally avoided with GMAW?
Spatter problems and poor weld appearance
The resistace to electrical current flow increases with it. Causing the electrode to heat
Gives arc voltage values to the control system of the feeder
Duty cycle

50. What is the required arc voltage used for short circuit transfer?
12 to 22 arc volts
(DCEP) Direct Current Electrode Positive or Reverse polarity
1/4 inch to 1/2 inch
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