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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. Is the arc voltage for spray transfer higher or lower than that used for short circuit transfer?
Higher 26 to 35 arc volts
Pressure - The rate of flow of a shielding gas
3
Compressed gas cylinder - Liquid filled cylinder - or a Liquid bulk system

2. What happens when the electrode extension is increased?
Pressure vessels and the piping industry
The resistace to electrical current flow increases with it. Causing the electrode to heat
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1/4 inch to 1/2 inch

3. 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
Constant current (CC)
Short- circuiting transfer - Globular transfer - Spray transfer

4. What is the preferred drive roll design for solid wires?
5.8 to 12.5 L/min
V groove or U groove
Constant- speed wire feeders and Voltage- sennsing wire feeders
Spatter problems and poor weld appearance

5. What controls the wire speed on a voltage sensing wire feeder?
Controls the rate of flow of a shielding gas to the gun nozzle
Cause flaking - which can clog the liner and contact tube
Molten metal is separated from the end of the filler wire by a squeezing force created by a magnetic field
The Arc voltage

6. Give a description of 'pinch effect'
Minimum distortion due to low heat input
Gives arc voltage values to the control system of the feeder
Spatter problems and poor weld appearance
Molten metal is separated from the end of the filler wire by a squeezing force created by a magnetic field

7. What current and polarity is generally used with GMAW?
DCEP (Direct Current Electrode Positive) Reverse Polarity
Welding process that joins metals by heating them with an electric arc
3
5.8 to 12.5 L/min

8. Draw a typical volt/amp curve that would be found with a power source designed for SMAW or GTAW
5.8 to 12.5 L/min
Gives arc voltage values to the control system of the feeder
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Duty cycle

9. Why is the term GMAW preferred over MIG or MAG?
When the filler wire is in direct contract with the base metal
Gas metal arc welding
These terms are quite restrictive and often technically incorrect
Dry ice can form within the flow control openings and cause blockage of shielding gas

10. A 10 minute cycle of welding time vs cooling time a given machine can handle.
Duty cycle
Guns
The Arc voltage
The negative side of a welding unit

11. What does voltage do in an electrical circuit?
Heat input is less than spray transfer - resulting in less distortion - Used in all positions due to controlling the weld metal freeze
Power source - wire feeder - welding gun - Spooled filler wire - Shielding gas - and a ground
Pressure - The rate of flow of a shielding gas
Voltage is the force that overcomes resistance to allow amperage flow

12. 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
To prevent drawing of liquid CO2 (Carbon Dioxide)
Reducing the gas source pressure to a constant working pressure

13. What effect does increasing and decreasing the inductance have on 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
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
Increasing inductance increases puddle fluidity - improves penatration - makes the bead flatter and smoother - and reduces spatter. To much inductance though will create erratic starts

14. Give a brief description of the GMAW process
Welding process that joins metals by heating them with an electric arc
If you dont know this check your phone
These terms are quite restrictive and often technically incorrect
Wire feed speed - Voltage control

15. What is the required arc voltage used for short circuit transfer?
Voltage is the force that overcomes resistance to allow amperage flow
Penetration and burn - off rate of the electrode
Electricaly operated valves that control the flow of shielding gas to the weld zone. The control switch located on the gun
12 to 22 arc volts

16. A machine with a 70% duty cycle can run at its max for 7 minutes with a cooling cycle of only _ minutes.
3
Constant- speed wire feeders and Voltage- sennsing wire feeders
Motor driven generators - Transformer rectifiers - and Inverter designs
National Electrical Manufactures Association

17. What does a flowmeter do and what does it measure?
Controls the rate of flow of a shielding gas to the gun nozzle
Welding process that joins metals by heating them with an electric arc
3
Guns

18. What is the maximum distance that hard wire can be successfully pushed?
Aluminum wire
15 feet (4.5 meters)
Wire feeds smoothly (yet will slip should a problem occur in the gun)
SMAW - GTAW

19. What would be an indication that the drive roll pressure is adjusted correctly?
Generally not as accurate
15 feet (4.5 meters)
Wire feeds smoothly (yet will slip should a problem occur in the gun)
Constant voltage (CV)

20. What is the effect of too much slope?
Insufficient current to melt the wire off cleanly
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The resistace to electrical current flow increases with it. Causing the electrode to heat
SMAW - GTAW

21. A pull type drive system is usually used on what type of material?
Puddle fluidity
Aluminum wire
1/4 inch to 1/2 inch
Penetration and burn - off rate of the electrode

22. What is a typical flow rate of CO2 for short circuit transfer?
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
Heat input is less than spray transfer - resulting in less distortion - Used in all positions due to controlling the weld metal freeze
5.8 to 12.5 L/min

23. Why is a line heater required when using GMAW?
The resistace to electrical current flow increases with it. Causing the electrode to heat
Compressed gas cylinder - Liquid filled cylinder - or a Liquid bulk system
Dry ice can form within the flow control openings and cause blockage of shielding gas
Electricaly operated valves that control the flow of shielding gas to the weld zone. The control switch located on the gun

24. List 3 wire drive systems and give a short description of each
(DCEP) Direct Current Electrode Positive or Reverse polarity
Wire feeds smoothly (yet will slip should a problem occur in the gun)
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
3

25. When using flat drive rolls with too much pressure on copper coated solid wires what problem could take place?
These terms are quite restrictive and often technically incorrect
Reducing the gas source pressure to a constant working pressure
When the filler wire is in direct contract with the base metal
Cause flaking - which can clog the liner and contact tube

26. Regulators control_____________ flowmeters SHOW____________.
Pressure vessels and the piping industry
85%
Power source - wire feeder - welding gun - Spooled filler wire - Shielding gas - and a ground
Pressure - The rate of flow of a shielding gas

27. Why is globular transfer generally avoided with GMAW?
85%
Spatter problems and poor weld appearance
National Electrical Manufactures Association
If you dont know this check your phone

28. Why must CO2 cylinders be used in the vertical position?
Short- circuiting transfer - Globular transfer - Spray transfer
DCEP (Direct Current Electrode Positive) 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
To prevent drawing of liquid CO2 (Carbon Dioxide)

29. What does the abbreviation NEMA stand for?
National Electrical Manufactures Association
Pressure - The rate of flow of a shielding gas
Minimum distortion due to low heat input
If you dont know this check your phone

30. What is the minimum % value of argon that must be present to use the spray transfer method of GMAW?
Reducing the gas source pressure to a constant working pressure
12 to 22 arc volts
85%
SMAW - GTAW

31. How many times per second does short circuiting take place?
Controls the rate of flow of a shielding gas to the gun nozzle
These terms are quite restrictive and often technically incorrect
Wire feeds smoothly (yet will slip should a problem occur in the gun)
20 to 200 times per second

32. What does the wire feeder control?
Constant current (CC)
Speed of the feed motor and - starting / stopping electrode feed
Controls the rate of flow of a shielding gas to the gun nozzle
DCEP (Direct Current Electrode Positive) Reverse Polarity

33. List the basic equipment requirements for the GMAW process
Pressure - The rate of flow of a shielding gas
Controls the rate of flow of a shielding gas to the gun nozzle
National Electrical Manufactures Association
Power source - wire feeder - welding gun - Spooled filler wire - Shielding gas - and a ground

34. What is the purpose of the pick- up lead on a voltage sensing wire feeder?
12 to 22 arc volts
Welding process that joins metals by heating them with an electric arc
Controls the rate of flow of a shielding gas to the gun nozzle
Gives arc voltage values to the control system of the feeder

35. What 2 controls are found on a GMAW set- up?
Wire feed speed - Voltage control
Higher 26 to 35 arc volts
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
The Arc voltage

36. What is the purpose of the shielding gas used in GMAW?
Shielding the molten weld metal from atmospheric contamination
Power source - wire feeder - welding gun - Spooled filler wire - Shielding gas - and a ground
1/4 inch to 1/2 inch
Welding process that joins metals by heating them with an electric arc

37. 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
Duty cycle
Aluminum wire
Cause flaking - which can clog the liner and contact tube

38. What is the recommended electrode stick- out for .035 solid wire?
1/4 inch to 1/2 inch
Power source - wire feeder - welding gun - Spooled filler wire - Shielding gas - and a ground
If you dont know this check your phone
(DCEP) Direct Current Electrode Positive or Reverse polarity

39. With straight polarity where is 2/3 of the arc energy?
To limit the short circuiting current so that spatter is reduced
When the filler wire is in direct contract with the base metal
The negative side of a welding unit
V groove or U groove

40. What type of power source is used with a constant speed wire feeder?
Constant voltage (CV)
SMAW - GTAW
Guns
The resistace to electrical current flow increases with it. Causing the electrode to heat

41. Draw a typical volt amp curve for a machine that is designed for GMAW
Cause flaking - which can clog the liner and contact tube
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
Minimum distortion due to low heat input
If you dont know this check your phone

42. What is the key advantage of short circuiting transfer?
By there current carrying capacity
Short- circuiting transfer - Globular transfer - Spray transfer
Wire feed speed - Voltage control
Minimum distortion due to low heat input

43. What is the main purpose of 'slope'?
Minimum distortion due to low heat input
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
To limit the short circuiting current so that spatter is reduced

44. What power sources are used with 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
AWS and CSA
Constant voltage (CV)
Motor driven generators - Transformer rectifiers - and Inverter designs

45. When is the metal transferred with short circuit transfer?
When the filler wire is in direct contract with the base metal
5.8 to 12.5 L/min
12 to 22 arc volts
Constant current (CC)

46. What are the 2 types of wire feeders available?
Constant- speed wire feeders and Voltage- sennsing wire feeders
Minimum distortion due to low heat input
Spatter problems and poor weld appearance
Minutes of elapsed time continually run (out of 10 minutes)

47. What wire are knurled drive rolls most commonly used on?
V groove or U groove
Pressure - The rate of flow of a shielding gas
Speed of the feed motor and - starting / stopping electrode feed
Flux cored wires

48. What is another term for electrode holders for GMAW?
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Cause flaking - which can clog the liner and contact tube
Guns
...

49. In the GMAW process what does voltage control?
Puddle fluidity
Flux cored wires
AWS and CSA
National Electrical Manufactures Association

50. Why is a fiber washer required and what cylinder gas requires it?
Dry ice can form within the flow control openings and cause blockage of shielding gas
...
Constant voltage (CV)
To prevent leakage - Carbon Dioxide (CO2)