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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 is the key advantage of short circuiting transfer?
By there current carrying capacity
Minimum distortion due to low heat input
DCEP (Direct Current Electrode Positive) Reverse Polarity
Motor driven generators - Transformer rectifiers - and Inverter designs

2. What 2 controls are found on a GMAW set- up?
Wire feed speed - Voltage control
Cause flaking - which can clog the liner and contact tube
National Electrical Manufactures Association
Constant current (CC)

3. What type of power source is used with a constant speed wire feeder?
To limit the short circuiting current so that spatter is reduced
Gives arc voltage values to the control system of the feeder
Electricaly operated valves that control the flow of shielding gas to the weld zone. The control switch located on the gun
Constant voltage (CV)

4. Is the arc voltage for spray transfer higher or lower than that used for short circuit transfer?
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)
Pressure vessels and the piping industry
Higher 26 to 35 arc volts

5. In the GMAW process what does voltage control?
Pressure - The rate of flow of a shielding gas
Welding Current - Filler wire diameter - arc length - type of shielding - position of the weld
Puddle fluidity
Generally not as accurate

6. What does the term GMAW identify?
Constant- speed wire feeders and Voltage- sennsing wire feeders
Gas metal arc welding
(DCEP) Direct Current Electrode Positive or Reverse polarity
Controls the rate of flow of a shielding gas to the gun nozzle

7. List the factors that determine the mode of metal transfer
Duty cycle
Welding Current - Filler wire diameter - arc length - type of shielding - position of the weld
Short- circuiting transfer - Globular transfer - Spray transfer
If you dont know this check your phone

8. With straight polarity where is 2/3 of the arc energy?
Insufficient current to melt the wire off cleanly
The Arc voltage
Compressed gas cylinder - Liquid filled cylinder - or a Liquid bulk system
The negative side of a welding unit

9. What is the reason glass 'tube' type flowmeters must have the tube mounted truly vertical?
...
Speed of the feed motor and - starting / stopping electrode feed
Guns
20 to 200 times per second

10. Draw a typical volt amp curve for a machine that is designed for GMAW
The time rate of response for the current rise and fall
By there current carrying capacity
If you dont know this check your phone
Higher 26 to 35 arc volts

11. What is the minimum % value of argon that must be present to use the spray transfer method of GMAW?
85%
15 feet (4.5 meters)
12 to 22 arc volts
Welding process that joins metals by heating them with an electric arc

12. What does the abbreviation NEMA stand for?
National Electrical Manufactures Association
The time rate of response for the current rise and fall
Shielding the molten weld metal from atmospheric contamination
Electricaly operated valves that control the flow of shielding gas to the weld zone. The control switch located on the gun

13. When using flat drive rolls with too much pressure on copper coated solid wires what problem could take place?
12 to 22 arc volts
Pressure - The rate of flow of a shielding gas
Cause flaking - which can clog the liner and contact tube
Wire feed speed

14. In the GMAW process what does amperage control?
Penetration and burn - off rate of the electrode
Insufficient current to melt the wire off cleanly
These terms are quite restrictive and often technically incorrect
Constant- speed wire feeders and Voltage- sennsing wire feeders

15. What would be an indication that the drive roll pressure is adjusted correctly?
DCEP (Direct Current Electrode Positive) Reverse Polarity
To limit the short circuiting current so that spatter is reduced
Wire feeds smoothly (yet will slip should a problem occur in the gun)
Wire feed speed - Voltage control

16. What is the purpose of the pick- up lead on a voltage sensing wire feeder?
Short- circuiting transfer - Globular transfer - Spray transfer
Gives arc voltage values to the control system of the feeder
1/4 inch to 1/2 inch
Cause flaking - which can clog the liner and contact tube

17. Why is globular transfer generally avoided with GMAW?
Puddle fluidity
To limit the short circuiting current so that spatter is reduced
Motor driven generators - Transformer rectifiers - and Inverter designs
Spatter problems and poor weld appearance

18. What power sources are used with the GMAW Process?
Insufficient current to melt the wire off cleanly
Voltage is the force that overcomes resistance to allow amperage flow
Motor driven generators - Transformer rectifiers - and Inverter designs
(DCEP) Direct Current Electrode Positive or Reverse polarity

19. What output on the welding machine is used to rate the duty cycle?
Speed of the feed motor and - starting / stopping electrode feed
Minutes of elapsed time continually run (out of 10 minutes)
Puddle fluidity
Minimum distortion due to low heat input

20. A 10 minute cycle of welding time vs cooling time a given machine can handle.
Welding Current - Filler wire diameter - arc length - type of shielding - position of the weld
National Electrical Manufactures Association
Duty cycle
The resistace to electrical current flow increases with it. Causing the electrode to heat

21. List the basic equipment requirements for the GMAW process
Wire feeds smoothly (yet will slip should a problem occur in the gun)
To prevent leakage - Carbon Dioxide (CO2)
Power source - wire feeder - welding gun - Spooled filler wire - Shielding gas - and a ground
(DCEP) Direct Current Electrode Positive or Reverse polarity

22. List the three methods of metal transfer with GMAW
V groove or U groove
The time rate of response for the current rise and fall
Welding Current - Filler wire diameter - arc length - type of shielding - position of the weld
Short- circuiting transfer - Globular transfer - Spray transfer

23. What is the recommended electrode stick- out for .035 solid wire?
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
Constant current (CC)
1/4 inch to 1/2 inch

24. What happens when the electrode extension is increased?
Dry ice can form within the flow control openings and cause blockage of shielding gas
The resistace to electrical current flow increases with it. Causing the electrode to heat
12 to 22 arc volts
Generally not as accurate

25. What is the purpose of a regulator and what does it indicate on its gauges?
Insufficient current to melt the wire off cleanly
V groove or U groove
Reducing the gas source pressure to a constant working pressure
Welding Current - Filler wire diameter - arc length - type of shielding - position of the weld

26. What is the preferred drive roll design for solid wires?
These terms are quite restrictive and often technically incorrect
85%
V groove or U groove
Constant- speed wire feeders and Voltage- sennsing wire feeders

27. How are GMAW guns rated?
By there current carrying capacity
Increasing inductance increases puddle fluidity - improves penatration - makes the bead flatter and smoother - and reduces spatter. To much inductance though will create erratic starts
Duty cycle
Short- circuiting transfer - Globular transfer - Spray transfer

28. What 2 organizations designate specifications for GMAW wires?
Welding process that joins metals by heating them with an electric arc
AWS and CSA
Flux cored wires
Dry ice can form within the flow control openings and cause blockage of shielding gas

29. What current and polarity is generally used with GMAW?
The resistace to electrical current flow increases with it. Causing the electrode to heat
To prevent leakage - Carbon Dioxide (CO2)
Motor driven generators - Transformer rectifiers - and Inverter designs
DCEP (Direct Current Electrode Positive) Reverse Polarity

30. What are the 2 types of wire feeders available?
Constant- speed wire feeders and Voltage- sennsing wire feeders
Higher 26 to 35 arc volts
Wire feeds smoothly (yet will slip should a problem occur in the gun)
Guns

31. 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
The negative side of a welding unit
Speed of the feed motor and - starting / stopping electrode feed

32. What does the wire feeder control?
Guns
Speed of the feed motor and - starting / stopping electrode feed
Generally not as accurate
Constant voltage (CV)

33. What is the required arc voltage used for short circuit transfer?
Reducing the gas source pressure to a constant working pressure
12 to 22 arc volts
20 to 200 times per second
These terms are quite restrictive and often technically incorrect

34. What is the main purpose of 'slope'?
Pressure - The rate of flow of a shielding gas
The negative side of a welding unit
Motor driven generators - Transformer rectifiers - and Inverter designs
To limit the short circuiting current so that spatter is reduced

35. Give a brief description of the GMAW process
The time rate of response for the current rise and fall
To prevent leakage - Carbon Dioxide (CO2)
DCEP (Direct Current Electrode Positive) Reverse Polarity
Welding process that joins metals by heating them with an electric arc

36. Why must CO2 cylinders be used in the vertical position?
Cause flaking - which can clog the liner and contact tube
To prevent drawing of liquid CO2 (Carbon Dioxide)
3
12 to 22 arc volts

37. List 3 wire drive systems and give a short description of each
SMAW - GTAW
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)
National Electrical Manufactures Association

38. 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
By there current carrying capacity
85%
Penetration and burn - off rate of the electrode

39. 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
Wire feed speed - Voltage control
1/4 inch to 1/2 inch
DCEP (Direct Current Electrode Positive) Reverse Polarity

40. What is another term for electrode holders for GMAW?
1/4 inch to 1/2 inch
If you dont know this check your phone
Guns
Generally not as accurate

41. What controls the wire speed on a voltage sensing wire feeder?
The Arc voltage
Pressure - The rate of flow of a shielding gas
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

42. Why is a line heater required when using GMAW?
These terms are quite restrictive and often technically incorrect
Shielding the molten weld metal from atmospheric contamination
Dry ice can form within the flow control openings and cause blockage of shielding gas
To limit the short circuiting current so that spatter is reduced

43. 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
Spatter problems and poor weld appearance
15 feet (4.5 meters)
Voltage is the force that overcomes resistance to allow amperage flow

44. Regulators control_____________ flowmeters SHOW____________.
15 feet (4.5 meters)
By there current carrying capacity
Shielding the molten weld metal from atmospheric contamination
Pressure - The rate of flow of a shielding gas

45. What is the disadvantage of the gauge preset type of regulator/flowmeter?
(DCEP) Direct Current Electrode Positive or Reverse polarity
Generally not as accurate
V groove or U groove
...

46. A pull type drive system is usually used on what type of material?
Higher 26 to 35 arc volts
Aluminum wire
Reducing the gas source pressure to a constant working pressure
Power source - wire feeder - welding gun - Spooled filler wire - Shielding gas - and a ground

47. What effect does increasing and decreasing the inductance have on the weld?
Heat input is less than spray transfer - resulting in less distortion - Used in all positions due to controlling the weld metal freeze
3
Reducing the gas source pressure to a constant working pressure
Increasing inductance increases puddle fluidity - improves penatration - makes the bead flatter and smoother - and reduces spatter. To much inductance though will create erratic starts

48. What controls amperage when using GMAW?
Puddle fluidity
Wire feed speed
15 feet (4.5 meters)
(DCEP) Direct Current Electrode Positive or Reverse polarity

49. What is the effect of too much slope?
Insufficient current to melt the wire off cleanly
Voltage is the force that overcomes resistance to allow amperage flow
Generally not as accurate
Motor driven generators - Transformer rectifiers - and Inverter designs

50. List several industries that would use GMAW
Pressure vessels and the piping industry
To prevent leakage - Carbon Dioxide (CO2)
To prevent drawing of liquid CO2 (Carbon Dioxide)
Power source - wire feeder - welding gun - Spooled filler wire - Shielding gas - and a ground