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Gas Metal Arc Welding

Instructions:

Answer 50 questions in 15 minutes.
If you are not ready to take this test, you can study here.
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. Why is globular transfer generally avoided with GMAW?
Spatter problems and poor weld appearance
National Electrical Manufactures Association
Electricaly operated valves that control the flow of shielding gas to the weld zone. The control switch located on the gun
Power source - wire feeder - welding gun - Spooled filler wire - Shielding gas - and a ground

2. What are the 2 types of wire feeders available?
Constant- speed wire feeders and Voltage- sennsing wire feeders
(DCEP) Direct Current Electrode Positive or Reverse polarity
5.8 to 12.5 L/min
Voltage is the force that overcomes resistance to allow amperage flow

3. What is the purpose of the pick- up lead on a voltage sensing wire feeder?
Speed of the feed motor and - starting / stopping electrode feed
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
Welding process that joins metals by heating them with an electric arc
Gives arc voltage values to the control system of the feeder

4. How many times per second does short circuiting take place?
20 to 200 times per second
These terms are quite restrictive and often technically incorrect
Wire feed speed - Voltage control
V groove or U groove

5. In the GMAW process what does amperage control?
Penetration and burn - off rate of the electrode
To limit the short circuiting current so that spatter is reduced
Constant current (CC)
National Electrical Manufactures Association

6. What 2 controls are found on a GMAW set- up?
Constant- speed wire feeders and Voltage- sennsing wire feeders
Wire feed speed - Voltage control
AWS and CSA
Welding Current - Filler wire diameter - arc length - type of shielding - position of the weld

7. What output on the welding machine is used to rate the duty cycle?
Gas metal arc welding
Flux cored wires
Pressure - The rate of flow of a shielding gas
Minutes of elapsed time continually run (out of 10 minutes)

8. What is the reason glass 'tube' type flowmeters must have the tube mounted truly vertical?
15 feet (4.5 meters)
Speed of the feed motor and - starting / stopping electrode feed
...
SMAW - GTAW

9. Regulators control_____________ flowmeters SHOW____________.
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
Constant current (CC)
Welding Current - Filler wire diameter - arc length - type of shielding - position of the weld

10. What is the minimum % value of argon that must be present to use the spray transfer method of GMAW?
National Electrical Manufactures Association
Welding process that joins metals by heating them with an electric arc
85%
Wire feed speed

11. What type of power source is used with a constant speed wire feeder?
These terms are quite restrictive and often technically incorrect
Constant voltage (CV)
Constant- speed wire feeders and Voltage- sennsing wire feeders
Spatter problems and poor weld appearance

12. When is the metal transferred with short circuit transfer?
Wire feeds smoothly (yet will slip should a problem occur in the gun)
(DCEP) Direct Current Electrode Positive or Reverse polarity
Duty cycle
When the filler wire is in direct contract with the base metal

13. Why is the term GMAW preferred over MIG or MAG?
Generally not as accurate
These terms are quite restrictive and often technically incorrect
By there current carrying capacity
AWS and CSA

14. What is the disadvantage of the gauge preset type of regulator/flowmeter?
Molten metal is separated from the end of the filler wire by a squeezing force created by a magnetic field
Generally not as accurate
Duty cycle
National Electrical Manufactures Association

15. What is another term for electrode holders for GMAW?
Welding process that joins metals by heating them with an electric arc
Guns
(DCEP) Direct Current Electrode Positive or Reverse polarity
Duty cycle

16. List the factors that determine the mode of metal transfer
Penetration and burn - off rate of the electrode
Puddle fluidity
Reducing the gas source pressure to a constant working pressure
Welding Current - Filler wire diameter - arc length - type of shielding - position of the weld

17. What controls the wire speed on a voltage sensing wire feeder?
To limit the short circuiting current so that spatter is reduced
Insufficient current to melt the wire off cleanly
When the filler wire is in direct contract with the base metal
The Arc voltage

18. What does inductance control?
Duty cycle
Wire feed speed - Voltage control
Guns
The time rate of response for the current rise and fall

19. A machine with a 70% duty cycle can run at its max for 7 minutes with a cooling cycle of only _ minutes.
3
...
Higher 26 to 35 arc volts
5.8 to 12.5 L/min

20. What power sources are used with the GMAW Process?
Motor driven generators - Transformer rectifiers - and Inverter designs
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
Speed of the feed motor and - starting / stopping electrode feed

21. 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)
Constant- speed wire feeders and Voltage- sennsing wire feeders
The negative side of a welding unit
Constant current (CC)

22. What is an advantage of pulsed arc transfer with GMAW?
85%
Minimum distortion due to low heat input
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

23. What happens when the electrode extension is increased?
The resistace to electrical current flow increases with it. Causing the electrode to heat
Motor driven generators - Transformer rectifiers - and Inverter designs
...
Gives arc voltage values to the control system of the feeder

24. What is the recommended electrode stick- out for .035 solid wire?
Duty cycle
Welding process that joins metals by heating them with an electric arc
1/4 inch to 1/2 inch
To limit the short circuiting current so that spatter is reduced

25. What effect does increasing and decreasing the inductance have on the weld?
5.8 to 12.5 L/min
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 feed speed - Voltage control
V groove or U groove

26. List 3 wire drive systems and give a short description of each
12 to 22 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
20 to 200 times per second
Speed of the feed motor and - starting / stopping electrode feed

27. What is the purpose of the shielding gas used in GMAW?
Shielding the molten weld metal from atmospheric contamination
Pressure - The rate of flow of a shielding gas
To prevent drawing of liquid CO2 (Carbon Dioxide)
Gives arc voltage values to the control system of the feeder

28. Give a description of 'pinch effect'
Wire feed speed - Voltage control
Power source - wire feeder - welding gun - Spooled filler wire - Shielding gas - and a ground
Generally not as accurate
Molten metal is separated from the end of the filler wire by a squeezing force created by a magnetic field

29. A pull type drive system is usually used on what type of material?
Aluminum wire
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
Compressed gas cylinder - Liquid filled cylinder - or a Liquid bulk system
(DCEP) Direct Current Electrode Positive or Reverse polarity

30. Draw a typical volt amp curve for a machine that is designed for GMAW
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
Wire feeds smoothly (yet will slip should a problem occur in the gun)
To prevent drawing of liquid CO2 (Carbon Dioxide)

31. What is a typical flow rate of CO2 for short circuit transfer?
When the filler wire is in direct contract with the base metal
Welding process that joins metals by heating them with an electric arc
The negative side of a welding unit
5.8 to 12.5 L/min

32. List the three methods of metal transfer with GMAW
Motor driven generators - Transformer rectifiers - and Inverter designs
Short- circuiting transfer - Globular transfer - Spray transfer
Cause flaking - which can clog the liner and contact tube
Minimum distortion due to low heat input

33. What is the purpose of a regulator and what does it indicate on its gauges?
20 to 200 times per second
Reducing the gas source pressure to a constant working pressure
Shielding the molten weld metal from atmospheric contamination
Minutes of elapsed time continually run (out of 10 minutes)

34. When using flat drive rolls with too much pressure on copper coated solid wires what problem could take place?
Minimum distortion due to low heat input
Cause flaking - which can clog the liner and contact tube
National Electrical Manufactures Association
SMAW - GTAW

35. What does the abbreviation NEMA stand for?
Compressed gas cylinder - Liquid filled cylinder - or a Liquid bulk system
National Electrical Manufactures Association
Wire feeds smoothly (yet will slip should a problem occur in the gun)
1/4 inch to 1/2 inch

36. What term is used to describe when the workpiece is hooked to the negative pole on the power source?
(DCEP) Direct Current Electrode Positive or Reverse polarity
DCEP (Direct Current Electrode Positive) Reverse Polarity
To limit the short circuiting current so that spatter is reduced
National Electrical Manufactures Association

37. Give a brief description of the GMAW process
Welding process that joins metals by heating them with an electric arc
Flux cored wires
Speed of the feed motor and - starting / stopping electrode feed
Wire feed speed

38. What is the key advantage of short circuiting transfer?
Minimum distortion due to low heat input
Puddle fluidity
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

39. What is a solenoid valve and what actuates it?
Constant voltage (CV)
Minimum distortion due to low heat input
Electricaly operated valves that control the flow of shielding gas to the weld zone. The control switch located on the gun
The Arc voltage

40. What controls amperage when using GMAW?
Wire feed speed
Wire feeds smoothly (yet will slip should a problem occur in the gun)
V groove or U groove
To prevent drawing of liquid CO2 (Carbon Dioxide)

41. What is the effect of too much slope?
DCEP (Direct Current Electrode Positive) Reverse Polarity
3
Insufficient current to melt the wire off cleanly
Controls the rate of flow of a shielding gas to the gun nozzle

42. What processes are constant current (CC) power sources designed to be used with?
By there current carrying capacity
SMAW - GTAW
20 to 200 times per second
Penetration and burn - off rate of the electrode

43. What 2 organizations designate specifications for GMAW wires?
Speed of the feed motor and - starting / stopping electrode feed
AWS and CSA
...
Short- circuiting transfer - Globular transfer - Spray transfer

44. What current and polarity is generally used with GMAW?
Speed of the feed motor and - starting / stopping electrode feed
DCEP (Direct Current Electrode Positive) Reverse Polarity
Wire feed speed - Voltage control
Motor driven generators - Transformer rectifiers - and Inverter designs

45. Why must CO2 cylinders be used in the vertical position?
To prevent drawing of liquid CO2 (Carbon Dioxide)
Short- circuiting transfer - Globular transfer - Spray transfer
Speed of the feed motor and - starting / stopping electrode feed
Shielding the molten weld metal from atmospheric contamination

46. Why is a line heater required when using GMAW?
Generally not as accurate
Insufficient current to melt the wire off cleanly
Dry ice can form within the flow control openings and cause blockage of shielding gas
Wire feed speed

47. What wire are knurled drive rolls most commonly used on?
Welding Current - Filler wire diameter - arc length - type of shielding - position of the weld
Flux cored wires
Aluminum wire
5.8 to 12.5 L/min

48. How are GMAW guns rated?
Guns
V groove or U groove
Constant voltage (CV)
By there current carrying capacity

49. What is the preferred drive roll design for solid wires?
V groove or U groove
Insufficient current to melt the wire off cleanly
(DCEP) Direct Current Electrode Positive or Reverse polarity
Molten metal is separated from the end of the filler wire by a squeezing force created by a magnetic field

50. What type of power source is commonly used with a voltage sensing wire feeder?
Welding Current - Filler wire diameter - arc length - type of shielding - position of the weld
These terms are quite restrictive and often technically incorrect
Constant current (CC)
...