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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. Why is globular transfer generally avoided with GMAW?
Spatter problems and poor weld appearance
Gas metal arc welding
Aluminum wire
Duty cycle

2. What is a solenoid valve and what actuates it?
Wire feed speed - Voltage control
Higher 26 to 35 arc volts
Electricaly operated valves that control the flow of shielding gas to the weld zone. The control switch located on the gun
Aluminum wire

3. What controls amperage when using GMAW?
Constant- speed wire feeders and Voltage- sennsing wire feeders
Minimum distortion due to low heat input
3
Wire feed speed

4. What type of power source is used with a constant speed wire feeder?
Puddle fluidity
Welding Current - Filler wire diameter - arc length - type of shielding - position of the weld
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

5. Why must CO2 cylinders be used in the vertical position?
Spatter problems and poor weld appearance
Reducing the gas source pressure to a constant working pressure
To prevent drawing of liquid CO2 (Carbon Dioxide)
15 feet (4.5 meters)

6. What is the purpose of a regulator and what does it indicate on its gauges?
Spatter problems and poor weld appearance
Reducing the gas source pressure to a constant working pressure
Aluminum wire
85%

7. What is a typical flow rate of CO2 for short circuit transfer?
If you dont know this check your phone
5.8 to 12.5 L/min
Constant- speed wire feeders and Voltage- sennsing wire feeders
Generally not as accurate

8. What does the wire feeder control?
Speed of the feed motor and - starting / stopping electrode feed
Compressed gas cylinder - Liquid filled cylinder - or a Liquid bulk system
Electricaly operated valves that control the flow of shielding gas to the weld zone. The control switch located on the gun
Reducing the gas source pressure to a constant working pressure

9. What power sources are used with the GMAW Process?
Gives arc voltage values to the control system of the feeder
Motor driven generators - Transformer rectifiers - and Inverter designs
Heat input is less than spray transfer - resulting in less distortion - Used in all positions due to controlling the weld metal freeze
Welding process that joins metals by heating them with an electric arc

10. What is the effect of too much slope?
Gas metal arc welding
Insufficient current to melt the wire off cleanly
The negative side of a welding unit
To prevent drawing of liquid CO2 (Carbon Dioxide)

11. What is the recommended electrode stick- out for .035 solid wire?
Constant voltage (CV)
Puddle fluidity
Higher 26 to 35 arc volts
1/4 inch to 1/2 inch

12. What is another term for electrode holders for GMAW?
By there current carrying capacity
Gives arc voltage values to the control system of the feeder
These terms are quite restrictive and often technically incorrect
Guns

13. Why is a line heater required when using GMAW?
Dry ice can form within the flow control openings and cause blockage of shielding gas
Shielding the molten weld metal from atmospheric contamination
Welding process that joins metals by heating them with an electric arc
Wire feed speed - Voltage control

14. A pull type drive system is usually used on what type of material?
Minutes of elapsed time continually run (out of 10 minutes)
1/4 inch to 1/2 inch
Speed of the feed motor and - starting / stopping electrode feed
Aluminum wire

15. 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)
Wire feed speed
National Electrical Manufactures Association
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

16. List 3 wire drive systems and give a short description of each
3
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
(DCEP) Direct Current Electrode Positive or Reverse polarity
If you dont know this check your phone

17. What is the reason glass 'tube' type flowmeters must have the tube mounted truly vertical?
15 feet (4.5 meters)
Shielding the molten weld metal from atmospheric contamination
...
Increasing inductance increases puddle fluidity - improves penatration - makes the bead flatter and smoother - and reduces spatter. To much inductance though will create erratic starts

18. With straight polarity where is 2/3 of the arc energy?
Pressure vessels and the piping industry
The negative side of a welding unit
Penetration and burn - off rate of the electrode
To prevent drawing of liquid CO2 (Carbon Dioxide)

19. List several industries that would use GMAW
Controls the rate of flow of a shielding gas to the gun nozzle
Pressure vessels and the piping industry
(DCEP) Direct Current Electrode Positive or Reverse polarity
3

20. Regulators control_____________ flowmeters SHOW____________.
Wire feed speed
Pressure - The rate of flow of a shielding gas
By there current carrying capacity
Controls the rate of flow of a shielding gas to the gun nozzle

21. What does the term GMAW identify?
3
Spatter problems and poor weld appearance
Gas metal arc welding
15 feet (4.5 meters)

22. What is the required arc voltage used for short circuit transfer?
12 to 22 arc volts
If you dont know this check your phone
Flux cored wires
Minutes of elapsed time continually run (out of 10 minutes)

23. What is the disadvantage of the gauge preset type of regulator/flowmeter?
AWS and CSA
Controls the rate of flow of a shielding gas to the gun nozzle
Motor driven generators - Transformer rectifiers - and Inverter designs
Generally not as accurate

24. Is the arc voltage for spray transfer higher or lower than that used for short circuit transfer?
Higher 26 to 35 arc volts
Welding Current - Filler wire diameter - arc length - type of shielding - position of the weld
If you dont know this check your phone
Reducing the gas source pressure to a constant working pressure

25. Draw a typical volt amp curve for a machine that is designed for GMAW
Pressure vessels and the piping industry
20 to 200 times per second
If you dont know this check your phone
When the filler wire is in direct contract with the base metal

26. What is the maximum distance that hard wire can be successfully pushed?
15 feet (4.5 meters)
Welding Current - Filler wire diameter - arc length - type of shielding - position of the weld
Power source - wire feeder - welding gun - Spooled filler wire - Shielding gas - and a ground
Heat input is less than spray transfer - resulting in less distortion - Used in all positions due to controlling the weld metal freeze

27. 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
By there current carrying capacity
Insufficient current to melt the wire off cleanly
Flux cored wires

28. What is an advantage of pulsed arc transfer with GMAW?
By there current carrying capacity
Heat input is less than spray transfer - resulting in less distortion - Used in all positions due to controlling the weld metal freeze
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

29. What 2 controls are found on a GMAW set- up?
Motor driven generators - Transformer rectifiers - and Inverter designs
Wire feed speed - Voltage control
Shielding the molten weld metal from atmospheric contamination
The negative side of a welding unit

30. What is the minimum % value of argon that must be present to use the spray transfer method of GMAW?
85%
Penetration and burn - off rate of the electrode
Reducing the gas source pressure to a constant working pressure
Heat input is less than spray transfer - resulting in less distortion - Used in all positions due to controlling the weld metal freeze

31. 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
12 to 22 arc volts
Welding Current - Filler wire diameter - arc length - type of shielding - position of the weld

32. What 2 organizations designate specifications for GMAW wires?
Minutes of elapsed time continually run (out of 10 minutes)
AWS and CSA
The Arc voltage
Spatter problems and poor weld appearance

33. What is the purpose of the pick- up lead on a voltage sensing wire feeder?
Gives arc voltage values to the control system of the feeder
Insufficient current to melt the wire off cleanly
Wire feeds smoothly (yet will slip should a problem occur in the gun)
National Electrical Manufactures Association

34. What is the key advantage of short circuiting transfer?
5.8 to 12.5 L/min
The resistace to electrical current flow increases with it. Causing the electrode to heat
Minimum distortion due to low heat input
SMAW - GTAW

35. List the factors that determine the mode of metal transfer
Motor driven generators - Transformer rectifiers - and Inverter designs
Welding Current - Filler wire diameter - arc length - type of shielding - position of the weld
When the filler wire is in direct contract with the base metal
15 feet (4.5 meters)

36. When using flat drive rolls with too much pressure on copper coated solid wires what problem could take place?
Flux cored wires
These terms are quite restrictive and often technically incorrect
Cause flaking - which can clog the liner and contact tube
Increasing inductance increases puddle fluidity - improves penatration - makes the bead flatter and smoother - and reduces spatter. To much inductance though will create erratic starts

37. What processes are constant current (CC) power sources designed to be used with?
1/4 inch to 1/2 inch
SMAW - GTAW
Compressed gas cylinder - Liquid filled cylinder - or a Liquid bulk system
Electricaly operated valves that control the flow of shielding gas to the weld zone. The control switch located on the gun

38. When is the metal transferred with short circuit transfer?
Guns
When the filler wire is in direct contract with the base metal
Reducing the gas source pressure to a constant working pressure
Duty cycle

39. 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
Penetration and burn - off rate of the electrode
Cause flaking - which can clog the liner and contact tube

40. Why is the term GMAW preferred over MIG or MAG?
DCEP (Direct Current Electrode Positive) Reverse Polarity
Dry ice can form within the flow control openings and cause blockage of shielding gas
These terms are quite restrictive and often technically incorrect
1/4 inch to 1/2 inch

41. 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
20 to 200 times per second
Gas metal arc welding

42. A machine with a 70% duty cycle can run at its max for 7 minutes with a cooling cycle of only _ minutes.
Guns
3
...
Minimum distortion due to low heat input

43. 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
Reducing the gas source pressure to a constant working pressure
Power source - wire feeder - welding gun - Spooled filler wire - Shielding gas - and a ground
V groove or U groove

44. What is the preferred drive roll design for solid wires?
V groove or U groove
12 to 22 arc volts
Reducing the gas source pressure to a constant working pressure
Compressed gas cylinder - Liquid filled cylinder - or a Liquid bulk system

45. What output on the welding machine is used to rate the duty cycle?
Minutes of elapsed time continually run (out of 10 minutes)
Gives arc voltage values to the control system of the feeder
5.8 to 12.5 L/min
Aluminum wire

46. In the GMAW process what does voltage control?
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
Puddle fluidity
Constant voltage (CV)
These terms are quite restrictive and often technically incorrect

47. List 3 forms compressed gases may be supplied for welding
Speed of the feed motor and - starting / stopping electrode feed
Pressure vessels and the piping industry
Welding Current - Filler wire diameter - arc length - type of shielding - position of the weld
Compressed gas cylinder - Liquid filled cylinder - or a Liquid bulk system

48. What controls the wire speed on a voltage sensing wire feeder?
20 to 200 times per second
Reducing the gas source pressure to a constant working pressure
Voltage is the force that overcomes resistance to allow amperage flow
The Arc voltage

49. Why is a fiber washer required and what cylinder gas requires it?
Cause flaking - which can clog the liner and contact tube
Compressed gas cylinder - Liquid filled cylinder - or a Liquid bulk system
The Arc voltage
To prevent leakage - Carbon Dioxide (CO2)

50. What type of power source is commonly used with a voltage sensing wire feeder?
Constant current (CC)
20 to 200 times per second
By there current carrying capacity
National Electrical Manufactures Association