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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. What is the required arc voltage used for short circuit transfer?
Welding process that joins metals by heating them with an electric arc
15 feet (4.5 meters)
Constant- speed wire feeders and Voltage- sennsing wire feeders
12 to 22 arc volts

2. Regulators control_____________ flowmeters SHOW____________.
Pressure - The rate of flow of a shielding gas
Spatter problems and poor weld appearance
Motor driven generators - Transformer rectifiers - and Inverter designs
3

3. What is an advantage of pulsed arc transfer with GMAW?
SMAW - GTAW
National Electrical Manufactures Association
Shielding the molten weld metal from atmospheric contamination
Heat input is less than spray transfer - resulting in less distortion - Used in all positions due to controlling the weld metal freeze

4. List the basic equipment requirements for the GMAW process
Insufficient current to melt the wire off cleanly
The resistace to electrical current flow increases with it. Causing the electrode to heat
Power source - wire feeder - welding gun - Spooled filler wire - Shielding gas - and a ground
Compressed gas cylinder - Liquid filled cylinder - or a Liquid bulk system

5. 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
Constant- speed wire feeders and Voltage- sennsing wire feeders
Insufficient current to melt the wire off cleanly
Aluminum wire

6. What is the disadvantage of the gauge preset type of regulator/flowmeter?
Dry ice can form within the flow control openings and cause blockage of shielding gas
AWS and CSA
...
Generally not as accurate

7. Give a description of 'pinch effect'
SMAW - GTAW
Molten metal is separated from the end of the filler wire by a squeezing force created by a magnetic field
Welding process that joins metals by heating them with an electric arc
Cause flaking - which can clog the liner and contact tube

8. What effect does increasing and decreasing the inductance have on the weld?
Flux cored wires
Short- circuiting transfer - Globular transfer - Spray transfer
Insufficient current to melt the wire off cleanly
Increasing inductance increases puddle fluidity - improves penatration - makes the bead flatter and smoother - and reduces spatter. To much inductance though will create erratic starts

9. What 2 controls are found on a GMAW set- up?
Wire feed speed - Voltage control
...
Generally not as accurate
Higher 26 to 35 arc volts

10. What does voltage do in an electrical circuit?
DCEP (Direct Current Electrode Positive) Reverse Polarity
To prevent leakage - Carbon Dioxide (CO2)
By there current carrying capacity
Voltage is the force that overcomes resistance to allow amperage flow

11. Is the arc voltage for spray transfer higher or lower than that used for short circuit transfer?
Higher 26 to 35 arc volts
Spatter problems and poor weld appearance
Wire feeds smoothly (yet will slip should a problem occur in the gun)
...

12. Why is globular transfer generally avoided with GMAW?
Compressed gas cylinder - Liquid filled cylinder - or a Liquid bulk system
These terms are quite restrictive and often technically incorrect
SMAW - GTAW
Spatter problems and poor weld appearance

13. Give a brief description of the GMAW process
The resistace to electrical current flow increases with it. Causing the electrode to heat
SMAW - GTAW
Pressure - The rate of flow of a shielding gas
Welding process that joins metals by heating them with an electric arc

14. What current and polarity is generally used with GMAW?
Reducing the gas source pressure to a constant working pressure
Dry ice can form within the flow control openings and cause blockage of shielding gas
(DCEP) Direct Current Electrode Positive or Reverse polarity
DCEP (Direct Current Electrode Positive) Reverse Polarity

15. Why must CO2 cylinders be used in the vertical position?
Welding Current - Filler wire diameter - arc length - type of shielding - position of the weld
Spatter problems and poor weld appearance
To prevent drawing of liquid CO2 (Carbon Dioxide)
Minimum distortion due to low heat input

16. What is the maximum distance that hard wire can be successfully pushed?
When the filler wire is in direct contract with the base metal
Speed of the feed motor and - starting / stopping electrode feed
The Arc voltage
15 feet (4.5 meters)

17. What is the main purpose of 'slope'?
3
By there current carrying capacity
5.8 to 12.5 L/min
To limit the short circuiting current so that spatter is reduced

18. What controls the wire speed on a voltage sensing wire feeder?
Gas metal arc welding
The Arc voltage
Flux cored wires
Guns

19. A pull type drive system is usually used on what type of material?
Compressed gas cylinder - Liquid filled cylinder - or a Liquid bulk system
SMAW - GTAW
Aluminum wire
5.8 to 12.5 L/min

20. 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
Duty cycle
Pressure vessels and the piping industry
Cause flaking - which can clog the liner and contact tube

21. A 10 minute cycle of welding time vs cooling time a given machine can handle.
Motor driven generators - Transformer rectifiers - and Inverter designs
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
Duty cycle

22. With straight polarity where is 2/3 of the arc energy?
Minimum distortion due to low heat input
The negative side of a welding unit
Wire feed speed - Voltage control
Wire feed speed

23. 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)
To prevent leakage - Carbon Dioxide (CO2)
Wire feed speed - Voltage control
Minutes of elapsed time continually run (out of 10 minutes)

24. List 3 wire drive systems and give a short description of each
SMAW - GTAW
Reducing the gas source pressure to a constant working pressure
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

25. What is the key advantage of short circuiting transfer?
Minimum distortion due to low heat input
Speed of the feed motor and - starting / stopping electrode feed
V groove or U groove
Shielding the molten weld metal from atmospheric contamination

26. What is the purpose of the shielding gas used in GMAW?
To prevent leakage - Carbon Dioxide (CO2)
Heat input is less than spray transfer - resulting in less distortion - Used in all positions due to controlling the weld metal freeze
12 to 22 arc volts
Shielding the molten weld metal from atmospheric contamination

27. What does the wire feeder control?
Speed of the feed motor and - starting / stopping electrode feed
5.8 to 12.5 L/min
To prevent leakage - Carbon Dioxide (CO2)
Dry ice can form within the flow control openings and cause blockage of shielding gas

28. What is another term for electrode holders for GMAW?
SMAW - GTAW
Guns
Flux cored wires
Shielding the molten weld metal from atmospheric contamination

29. In the GMAW process what does voltage control?
Electricaly operated valves that control the flow of shielding gas to the weld zone. The control switch located on the gun
Puddle fluidity
AWS and CSA
Generally not as accurate

30. List 3 forms compressed gases may be supplied for welding
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
(DCEP) Direct Current Electrode Positive or Reverse polarity
Gas metal arc welding

31. What is the recommended electrode stick- out for .035 solid wire?
1/4 inch to 1/2 inch
To prevent leakage - Carbon Dioxide (CO2)
Heat input is less than spray transfer - resulting in less distortion - Used in all positions due to controlling the weld metal freeze
20 to 200 times per second

32. What is a solenoid valve and what actuates it?
Controls the rate of flow of a shielding gas to the gun nozzle
Cause flaking - which can clog the liner and contact tube
If you dont know this check your phone
Electricaly operated valves that control the flow of shielding gas to the weld zone. The control switch located on the gun

33. What output on the welding machine is used to rate the duty cycle?
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
5.8 to 12.5 L/min
Minutes of elapsed time continually run (out of 10 minutes)

34. A machine with a 70% duty cycle can run at its max for 7 minutes with a cooling cycle of only _ minutes.
Short- circuiting transfer - Globular transfer - Spray transfer
3
Shielding the molten weld metal from atmospheric contamination
20 to 200 times per second

35. How many times per second does short circuiting take place?
Shielding the molten weld metal from atmospheric contamination
20 to 200 times per second
Power source - wire feeder - welding gun - Spooled filler wire - Shielding gas - and a ground
Short- circuiting transfer - Globular transfer - Spray transfer

36. What does the term GMAW identify?
The negative side of a welding unit
Penetration and burn - off rate of the electrode
Gas metal arc welding
Dry ice can form within the flow control openings and cause blockage of shielding gas

37. What power sources are used with the GMAW Process?
...
Motor driven generators - Transformer rectifiers - and Inverter designs
SMAW - GTAW
Reducing the gas source pressure to a constant working pressure

38. Why is a fiber washer required and what cylinder gas requires it?
To prevent leakage - Carbon Dioxide (CO2)
The resistace to electrical current flow increases with it. Causing the electrode to heat
Power source - wire feeder - welding gun - Spooled filler wire - Shielding gas - and a ground
To prevent drawing of liquid CO2 (Carbon Dioxide)

39. List the factors that determine the mode of metal transfer
15 feet (4.5 meters)
Pressure vessels and the piping industry
If you dont know this check your phone
Welding Current - Filler wire diameter - arc length - type of shielding - position of the weld

40. Why is the term GMAW preferred over MIG or MAG?
Insufficient current to melt the wire off cleanly
These terms are quite restrictive and often technically incorrect
Molten metal is separated from the end of the filler wire by a squeezing force created by a magnetic field
3

41. What is the purpose of a regulator and what does it indicate on its gauges?
Constant current (CC)
Reducing the gas source pressure to a constant working pressure
National Electrical Manufactures Association
Aluminum wire

42. When using flat drive rolls with too much pressure on copper coated solid wires what problem could take place?
Wire feed speed
15 feet (4.5 meters)
Cause flaking - which can clog the liner and contact tube
Wire feeds smoothly (yet will slip should a problem occur in the gun)

43. What is the purpose of the pick- up lead on a voltage sensing wire feeder?
To prevent leakage - Carbon Dioxide (CO2)
Gives arc voltage values to the control system of the feeder
Pressure - The rate of flow of a shielding gas
To limit the short circuiting current so that spatter is reduced

44. What is the reason glass 'tube' type flowmeters must have the tube mounted truly vertical?
(DCEP) Direct Current Electrode Positive or Reverse polarity
Puddle fluidity
85%
...

45. How are GMAW guns rated?
Minimum distortion due to low heat input
By there current carrying capacity
Motor driven generators - Transformer rectifiers - and Inverter designs
To limit the short circuiting current so that spatter is reduced

46. Draw a typical volt amp curve for a machine that is designed for GMAW
20 to 200 times per second
Cause flaking - which can clog the liner and contact tube
If you dont know this check your phone
By there current carrying capacity

47. What controls amperage when using GMAW?
To prevent leakage - Carbon Dioxide (CO2)
Voltage is the force that overcomes resistance to allow amperage flow
If you dont know this check your phone
Wire feed speed

48. What happens when the electrode extension is increased?
The resistace to electrical current flow increases with it. Causing the electrode to heat
15 feet (4.5 meters)
Puddle fluidity
Aluminum wire

49. What does the abbreviation NEMA stand for?
National Electrical Manufactures Association
Shielding the molten weld metal from atmospheric contamination
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

50. What is the preferred drive roll design for solid wires?
V groove or U groove
To prevent drawing of liquid CO2 (Carbon Dioxide)
Wire feed speed
Pressure vessels and the piping industry