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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 does the wire feeder control?
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Constant- speed wire feeders and Voltage- sennsing wire feeders
Speed of the feed motor and - starting / stopping electrode feed
Minimum distortion due to low heat input

2. What is a typical flow rate of CO2 for short circuit transfer?
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
National Electrical Manufactures Association
Constant current (CC)

3. What is the purpose of the shielding gas used in GMAW?
Speed of the feed motor and - starting / stopping electrode feed
Shielding the molten weld metal from atmospheric contamination
Constant voltage (CV)
National Electrical Manufactures Association

4. When is the metal transferred with short circuit transfer?
20 to 200 times per second
To prevent leakage - Carbon Dioxide (CO2)
When the filler wire is in direct contract with the base metal
Constant- speed wire feeders and Voltage- sennsing wire feeders

5. Draw a typical volt/amp curve that would be found with a power source designed for SMAW or GTAW
To prevent leakage - Carbon Dioxide (CO2)
The time rate of response for the current rise and fall
Shielding the molten weld metal from atmospheric contamination
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6. What 2 controls are found on a GMAW set- up?
Minimum distortion due to low heat input
The negative side of a welding unit
1/4 inch to 1/2 inch
Wire feed speed - Voltage control

7. With straight polarity where is 2/3 of the arc energy?
SMAW - GTAW
V groove or U groove
The negative side of a welding unit
Welding process that joins metals by heating them with an electric arc

8. In the GMAW process what does amperage control?
Higher 26 to 35 arc volts
Dry ice can form within the flow control openings and cause blockage of shielding gas
Cause flaking - which can clog the liner and contact tube
Penetration and burn - off rate of the electrode

9. What does the term GMAW identify?
Gas metal arc welding
5.8 to 12.5 L/min
Guns
Motor driven generators - Transformer rectifiers - and Inverter designs

10. What does inductance control?
Increasing inductance increases puddle fluidity - improves penatration - makes the bead flatter and smoother - and reduces spatter. To much inductance though will create erratic starts
V groove or U groove
To prevent drawing of liquid CO2 (Carbon Dioxide)
The time rate of response for the current rise and fall

11. List 3 forms compressed gases may be supplied for welding
Reducing the gas source pressure to a constant working pressure
Electricaly operated valves that control the flow of shielding gas to the weld zone. The control switch located on the gun
Aluminum wire
Compressed gas cylinder - Liquid filled cylinder - or a Liquid bulk system

12. What is a solenoid valve and what actuates it?
Welding Current - Filler wire diameter - arc length - type of shielding - position of the weld
Electricaly operated valves that control the flow of shielding gas to the weld zone. The control switch located on the gun
Compressed gas cylinder - Liquid filled cylinder - or a Liquid bulk system
Constant current (CC)

13. What is the preferred drive roll design for solid wires?
Pressure - The rate of flow of a shielding gas
85%
V groove or U groove
5.8 to 12.5 L/min

14. Why is globular transfer generally avoided with GMAW?
AWS and CSA
The Arc voltage
Reducing the gas source pressure to a constant working pressure
Spatter problems and poor weld appearance

15. Draw a typical volt amp curve for a machine that is designed for GMAW
3
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Welding Current - Filler wire diameter - arc length - type of shielding - position of the weld
The negative side of a welding unit

16. What effect does increasing and decreasing the inductance have on the weld?
1/4 inch to 1/2 inch
Controls the rate of flow of a shielding gas to the gun nozzle
Increasing inductance increases puddle fluidity - improves penatration - makes the bead flatter and smoother - and reduces spatter. To much inductance though will create erratic starts
Speed of the feed motor and - starting / stopping electrode feed

17. What is the purpose of the pick- up lead on a voltage sensing wire feeder?
Guns
When the filler wire is in direct contract with the base metal
To prevent leakage - Carbon Dioxide (CO2)
Gives arc voltage values to the control system of the feeder

18. 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
AWS and CSA
Pressure - The rate of flow of a shielding gas
Heat input is less than spray transfer - resulting in less distortion - Used in all positions due to controlling the weld metal freeze

19. What is the minimum % value of argon that must be present to use the spray transfer method of GMAW?
Dry ice can form within the flow control openings and cause blockage of shielding gas
85%
(DCEP) Direct Current Electrode Positive or Reverse polarity
By there current carrying capacity

20. How are GMAW guns rated?
By there current carrying capacity
15 feet (4.5 meters)
These terms are quite restrictive and often technically incorrect
Insufficient current to melt the wire off cleanly

21. Give a description of 'pinch effect'
Molten metal is separated from the end of the filler wire by a squeezing force created by a magnetic field
National Electrical Manufactures Association
Power source - wire feeder - welding gun - Spooled filler wire - Shielding gas - and a ground
Wire feed speed - Voltage control

22. What output on the welding machine is used to rate the duty cycle?
Generally not as accurate
Electricaly operated valves that control the flow of shielding gas to the weld zone. The control switch located on the gun
Minutes of elapsed time continually run (out of 10 minutes)
Wire feed speed - Voltage control

23. Regulators control_____________ flowmeters SHOW____________.
Heat input is less than spray transfer - resulting in less distortion - Used in all positions due to controlling the weld metal freeze
Gas metal arc welding
Pressure - The rate of flow of a shielding gas
Electricaly operated valves that control the flow of shielding gas to the weld zone. The control switch located on the gun

24. What happens when the electrode extension is increased?
Wire feed speed
The resistace to electrical current flow increases with it. Causing the electrode to heat
Dry ice can form within the flow control openings and cause blockage of shielding gas
The time rate of response for the current rise and fall

25. What wire are knurled drive rolls most commonly used on?
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
Pressure - The rate of flow of a shielding gas
Wire feeds smoothly (yet will slip should a problem occur in the gun)
Flux cored wires

26. Give a brief description of the GMAW process
Welding process that joins metals by heating them with an electric arc
Welding Current - Filler wire diameter - arc length - type of shielding - position of the weld
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Wire feed speed - Voltage control

27. What is the main purpose of 'slope'?
Flux cored wires
Gas metal arc welding
Aluminum wire
To limit the short circuiting current so that spatter is reduced

28. Why is a line heater required when using GMAW?
Pressure - The rate of flow of a shielding gas
Dry ice can form within the flow control openings and cause blockage of shielding gas
Compressed gas cylinder - Liquid filled cylinder - or a Liquid bulk system
Minimum distortion due to low heat input

29. How many times per second does short circuiting take place?
Shielding the molten weld metal from atmospheric contamination
Spatter problems and poor weld appearance
20 to 200 times per second
Welding Current - Filler wire diameter - arc length - type of shielding - position of the weld

30. What is an advantage of pulsed arc transfer with GMAW?
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
Heat input is less than spray transfer - resulting in less distortion - Used in all positions due to controlling the weld metal freeze
To prevent drawing of liquid CO2 (Carbon Dioxide)

31. A pull type drive system is usually used on what type of material?
Aluminum wire
These terms are quite restrictive and often technically incorrect
When the filler wire is in direct contract with the base metal
Insufficient current to melt the wire off cleanly

32. A 10 minute cycle of welding time vs cooling time a given machine can handle.
Speed of the feed motor and - starting / stopping electrode feed
Duty cycle
Voltage is the force that overcomes resistance to allow amperage flow
Dry ice can form within the flow control openings and cause blockage of shielding gas

33. What type of power source is commonly used with a voltage sensing wire feeder?
Constant current (CC)
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
Dry ice can form within the flow control openings and cause blockage of shielding gas

34. What is the effect of too much slope?
The negative side of a welding unit
Insufficient current to melt the wire off cleanly
Constant current (CC)
12 to 22 arc volts

35. What are the 2 types of wire feeders available?
Higher 26 to 35 arc volts
Reducing the gas source pressure to a constant working pressure
Minimum distortion due to low heat input
Constant- speed wire feeders and Voltage- sennsing wire feeders

36. List the basic equipment requirements for the GMAW process
The time rate of response for the current rise and fall
15 feet (4.5 meters)
Gas metal arc welding
Power source - wire feeder - welding gun - Spooled filler wire - Shielding gas - and a ground

37. What is the recommended electrode stick- out for .035 solid wire?
1/4 inch to 1/2 inch
Welding process that joins metals by heating them with an electric arc
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Spatter problems and poor weld appearance

38. List the three methods of metal transfer with GMAW
Short- circuiting transfer - Globular transfer - Spray transfer
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 negative side of a welding unit
When the filler wire is in direct contract with the base metal

39. A machine with a 70% duty cycle can run at its max for 7 minutes with a cooling cycle of only _ minutes.
3
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Short- circuiting transfer - Globular transfer - Spray transfer
15 feet (4.5 meters)

40. What controls amperage when using GMAW?
Pressure vessels and the piping industry
Spatter problems and poor weld appearance
Duty cycle
Wire feed speed

41. What does the abbreviation NEMA stand for?
Gives arc voltage values to the control system of the feeder
Welding process that joins metals by heating them with an electric arc
Wire feed speed - Voltage control
National Electrical Manufactures Association

42. In the GMAW process what does voltage control?
Higher 26 to 35 arc volts
Puddle fluidity
Dry ice can form within the flow control openings and cause blockage of shielding gas
These terms are quite restrictive and often technically incorrect

43. What is the required arc voltage used for short circuit transfer?
Minutes of elapsed time continually run (out of 10 minutes)
12 to 22 arc volts
Wire feed speed - Voltage control
Pressure - The rate of flow of a shielding gas

44. 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)
Aluminum wire
20 to 200 times per second
Constant- speed wire feeders and Voltage- sennsing wire feeders

45. What is the maximum distance that hard wire can be successfully pushed?
1/4 inch to 1/2 inch
15 feet (4.5 meters)
Increasing inductance increases puddle fluidity - improves penatration - makes the bead flatter and smoother - and reduces spatter. To much inductance though will create erratic starts
Minutes of elapsed time continually run (out of 10 minutes)

46. What term is used to describe when the workpiece is hooked to the negative pole on the power source?
Flux cored wires
Minutes of elapsed time continually run (out of 10 minutes)
(DCEP) Direct Current Electrode Positive or Reverse polarity
Insufficient current to melt the wire off cleanly

47. What power sources are used with the GMAW Process?
Motor driven generators - Transformer rectifiers - and Inverter designs
5.8 to 12.5 L/min
Speed of the feed motor and - starting / stopping electrode feed
Constant- speed wire feeders and Voltage- sennsing wire feeders

48. What type of power source is used with a constant speed wire feeder?
AWS and CSA
12 to 22 arc volts
Constant voltage (CV)
1/4 inch to 1/2 inch

49. What is the disadvantage of the gauge preset type of regulator/flowmeter?
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
Minutes of elapsed time continually run (out of 10 minutes)
5.8 to 12.5 L/min

50. What 2 organizations designate specifications for GMAW wires?
AWS and CSA
Generally not as accurate
V groove or U groove
Dry ice can form within the flow control openings and cause blockage of shielding gas