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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 recommended electrode stick- out for .035 solid wire?
Insufficient current to melt the wire off cleanly
Voltage is the force that overcomes resistance to allow amperage flow
1/4 inch to 1/2 inch
Constant- speed wire feeders and Voltage- sennsing wire feeders

2. What does the term GMAW identify?
Gas metal arc welding
Puddle fluidity
Flux cored wires
Electricaly operated valves that control the flow of shielding gas to the weld zone. The control switch located on the gun

3. 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
The negative side of a welding unit
Short- circuiting transfer - Globular transfer - Spray transfer
Welding process that joins metals by heating them with an electric arc

4. In the GMAW process what does amperage control?
Penetration and burn - off rate of the electrode
20 to 200 times per second
Heat input is less than spray transfer - resulting in less distortion - Used in all positions due to controlling the weld metal freeze
Compressed gas cylinder - Liquid filled cylinder - or a Liquid bulk system

5. When using flat drive rolls with too much pressure on copper coated solid wires what problem could take place?
Constant- speed wire feeders and Voltage- sennsing wire feeders
Cause flaking - which can clog the liner and contact tube
Speed of the feed motor and - starting / stopping electrode feed
The negative side of a welding unit

6. Regulators control_____________ flowmeters SHOW____________.
Wire feed speed
Reducing the gas source pressure to a constant working pressure
Pressure - The rate of flow of a shielding gas
The time rate of response for the current rise and fall

7. What is the required arc voltage used for short circuit transfer?
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
Flux cored wires
12 to 22 arc volts

8. What output on the welding machine is used to rate the duty cycle?
Minutes of elapsed time continually run (out of 10 minutes)
Insufficient current to melt the wire off cleanly
Aluminum wire
Electricaly operated valves that control the flow of shielding gas to the weld zone. The control switch located on the gun

9. What is the purpose of the pick- up lead on a voltage sensing wire feeder?
Pressure vessels and the piping industry
Gas metal arc welding
Puddle fluidity
Gives arc voltage values to the control system of the feeder

10. A 10 minute cycle of welding time vs cooling time a given machine can handle.
Controls the rate of flow of a shielding gas to the gun nozzle
Duty cycle
Gas metal arc welding
Minimum distortion due to low heat input

11. Why is globular transfer generally avoided with GMAW?
Flux cored wires
Spatter problems and poor weld appearance
Aluminum wire
These terms are quite restrictive and often technically incorrect

12. List the three methods of metal transfer with GMAW
When the filler wire is in direct contract with the base metal
AWS and CSA
Short- circuiting transfer - Globular transfer - Spray transfer
Heat input is less than spray transfer - resulting in less distortion - Used in all positions due to controlling the weld metal freeze

13. How are GMAW guns rated?
Insufficient current to melt the wire off cleanly
(DCEP) Direct Current Electrode Positive or Reverse polarity
Penetration and burn - off rate of the electrode
By there current carrying capacity

14. What is the maximum distance that hard wire can be successfully pushed?
National Electrical Manufactures Association
Wire feeds smoothly (yet will slip should a problem occur in the gun)
15 feet (4.5 meters)
Gives arc voltage values to the control system of the feeder

15. Why is a fiber washer required and what cylinder gas requires it?
Gas metal arc welding
12 to 22 arc volts
Compressed gas cylinder - Liquid filled cylinder - or a Liquid bulk system
To prevent leakage - Carbon Dioxide (CO2)

16. What does voltage do in an electrical circuit?
Voltage is the force that overcomes resistance to allow amperage flow
If you dont know this check your phone
These terms are quite restrictive and often technically incorrect
Reducing the gas source pressure to a constant working pressure

17. What controls the wire speed on a voltage sensing wire feeder?
Penetration and burn - off rate of the electrode
SMAW - GTAW
Generally not as accurate
The Arc voltage

18. What controls amperage when using GMAW?
Wire feed speed
Dry ice can form within the flow control openings and cause blockage of 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
(DCEP) Direct Current Electrode Positive or Reverse polarity

19. What type of power source is used with a constant speed wire feeder?
Voltage is the force that overcomes resistance to allow amperage flow
Higher 26 to 35 arc volts
Constant voltage (CV)
The negative side of a welding unit

20. What power sources are used with the GMAW Process?
5.8 to 12.5 L/min
If you dont know this check your phone
Shielding the molten weld metal from atmospheric contamination
Motor driven generators - Transformer rectifiers - and Inverter designs

21. What does inductance control?
Wire feeds smoothly (yet will slip should a problem occur in the gun)
The time rate of response for the current rise and fall
Wire feed speed
3

22. Why is a line heater required when using GMAW?
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
If you dont know this check your phone
Controls the rate of flow of a shielding gas to the gun nozzle
Dry ice can form within the flow control openings and cause blockage of shielding gas

23. How many times per second does short circuiting take place?
Increasing inductance increases puddle fluidity - improves penatration - makes the bead flatter and smoother - and reduces spatter. To much inductance though will create erratic starts
Short- circuiting transfer - Globular transfer - Spray transfer
20 to 200 times per second
Aluminum wire

24. List 3 forms compressed gases may be supplied for welding
Motor driven generators - Transformer rectifiers - and Inverter designs
The time rate of response for the current rise and fall
Minimum distortion due to low heat input
Compressed gas cylinder - Liquid filled cylinder - or a Liquid bulk system

25. What is the preferred drive roll design for solid wires?
Insufficient current to melt the wire off cleanly
V groove or U groove
If you dont know this check your phone
The Arc voltage

26. With straight polarity where is 2/3 of the arc energy?
Penetration and burn - off rate of the electrode
The negative side of a welding unit
The time rate of response for the current rise and fall
Wire feed speed - Voltage control

27. What type of power source is commonly used with a voltage sensing wire feeder?
Puddle fluidity
Gas metal arc welding
Wire feed speed
Constant current (CC)

28. What are the 2 types of wire feeders available?
Wire feeds smoothly (yet will slip should a problem occur in the gun)
Short- circuiting transfer - Globular transfer - Spray transfer
Constant- speed wire feeders and Voltage- sennsing wire feeders
Generally not as accurate

29. What is the key advantage of short circuiting transfer?
Compressed gas cylinder - Liquid filled cylinder - or a Liquid bulk system
Minimum distortion due to low heat input
Duty cycle
Constant voltage (CV)

30. What does the abbreviation NEMA stand for?
National Electrical Manufactures Association
To limit the short circuiting current so that spatter is reduced
Wire feeds smoothly (yet will slip should a problem occur in the gun)
12 to 22 arc volts

31. Is the arc voltage for spray transfer higher or lower than that used for short circuit transfer?
The negative side of a welding unit
Puddle fluidity
SMAW - GTAW
Higher 26 to 35 arc volts

32. A machine with a 70% duty cycle can run at its max for 7 minutes with a cooling cycle of only _ minutes.
Constant current (CC)
3
Pressure - The rate of flow of a shielding gas
12 to 22 arc volts

33. What is a solenoid valve and what actuates it?
Insufficient current to melt the wire off cleanly
12 to 22 arc volts
Electricaly operated valves that control the flow of shielding gas to the weld zone. The control switch located on the gun
AWS and CSA

34. What effect does increasing and decreasing the inductance have on the weld?
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
Gas metal arc welding
To prevent drawing of liquid CO2 (Carbon Dioxide)

35. List 3 wire drive systems and give a short description of each
Constant voltage (CV)
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
By there current carrying capacity
To prevent leakage - Carbon Dioxide (CO2)

36. Why must CO2 cylinders be used in the vertical position?
To prevent drawing of liquid CO2 (Carbon Dioxide)
Cause flaking - which can clog the liner and contact tube
20 to 200 times per second
Gives arc voltage values to the control system of the feeder

37. A pull type drive system is usually used on what type of material?
If you dont know this check your phone
Aluminum wire
DCEP (Direct Current Electrode Positive) Reverse Polarity
The resistace to electrical current flow increases with it. Causing the electrode to heat

38. What does the wire feeder control?
Motor driven generators - Transformer rectifiers - and Inverter designs
15 feet (4.5 meters)
DCEP (Direct Current Electrode Positive) Reverse Polarity
Speed of the feed motor and - starting / stopping electrode feed

39. What is the reason glass 'tube' type flowmeters must have the tube mounted truly vertical?
To prevent leakage - Carbon Dioxide (CO2)
By there current carrying capacity
...
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

40. What is a typical flow rate of CO2 for short circuit 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
Minimum distortion due to low heat input
5.8 to 12.5 L/min
Pressure vessels and the piping industry

41. What is the minimum % value of argon that must be present to use the spray transfer method of GMAW?
85%
5.8 to 12.5 L/min
Short- circuiting transfer - Globular transfer - Spray transfer
The resistace to electrical current flow increases with it. Causing the electrode to heat

42. What happens when the electrode extension is increased?
V groove or U groove
The resistace to electrical current flow increases with it. Causing the electrode to heat
Minimum distortion due to low heat input
Welding Current - Filler wire diameter - arc length - type of shielding - position of the weld

43. List the factors that determine the mode of metal transfer
85%
Generally not as accurate
(DCEP) Direct Current Electrode Positive or Reverse polarity
Welding Current - Filler wire diameter - arc length - type of shielding - position of the weld

44. Give a brief description of the GMAW process
Constant- speed wire feeders and Voltage- sennsing wire feeders
Controls the rate of flow of a shielding gas to the gun nozzle
National Electrical Manufactures Association
Welding process that joins metals by heating them with an electric arc

45. What 2 organizations designate specifications for GMAW wires?
20 to 200 times per second
Pressure vessels and the piping industry
1/4 inch to 1/2 inch
AWS and CSA

46. In the GMAW process what does voltage control?
Wire feeds smoothly (yet will slip should a problem occur in the gun)
Penetration and burn - off rate of the electrode
SMAW - GTAW
Puddle fluidity

47. 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)
Motor driven generators - Transformer rectifiers - and Inverter designs
Generally not as accurate
1/4 inch to 1/2 inch

48. List the basic equipment requirements for the GMAW process
Welding process that joins metals by heating them with an electric arc
Power source - wire feeder - welding gun - Spooled filler wire - Shielding gas - and a ground
85%
V groove or U groove

49. What 2 controls are found on a GMAW set- up?
(DCEP) Direct Current Electrode Positive or Reverse polarity
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
Wire feed speed - Voltage control

50. What is the purpose of the shielding gas used in GMAW?
Gas metal arc welding
Shielding the molten weld metal from atmospheric contamination
Constant current (CC)
Increasing inductance increases puddle fluidity - improves penatration - makes the bead flatter and smoother - and reduces spatter. To much inductance though will create erratic starts