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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 a solenoid valve and what actuates it?
National Electrical Manufactures Association
Electricaly operated valves that control the flow of shielding gas to the weld zone. The control switch located on the gun
(DCEP) Direct Current Electrode Positive or Reverse polarity
Speed of the feed motor and - starting / stopping electrode feed

2. What does the abbreviation NEMA stand for?
Constant voltage (CV)
National Electrical Manufactures Association
To prevent drawing of liquid CO2 (Carbon Dioxide)
Penetration and burn - off rate of the electrode

3. What is the purpose of a regulator and what does it indicate on its gauges?
5.8 to 12.5 L/min
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
20 to 200 times per second

4. What controls the wire speed on a voltage sensing wire feeder?
These terms are quite restrictive and often technically incorrect
Minimum distortion due to low heat input
The Arc voltage
Puddle fluidity

5. What would be an indication that the drive roll pressure is adjusted correctly?
To prevent drawing of liquid CO2 (Carbon Dioxide)
Wire feeds smoothly (yet will slip should a problem occur in the gun)
85%
Pressure - The rate of flow of a shielding gas

6. List the three methods of metal transfer with GMAW
Short- circuiting transfer - Globular transfer - Spray transfer
Electricaly operated valves that control the flow of shielding gas to the weld zone. The control switch located on the gun
Puddle fluidity
National Electrical Manufactures Association

7. What processes are constant current (CC) power sources designed to be used with?
Duty cycle
Cause flaking - which can clog the liner and contact tube
Electricaly operated valves that control the flow of shielding gas to the weld zone. The control switch located on the gun
SMAW - GTAW

8. What does the term GMAW identify?
Pressure - The rate of flow of a shielding gas
Dry ice can form within the flow control openings and cause blockage of shielding gas
Gas metal arc welding
Speed of the feed motor and - starting / stopping electrode feed

9. When is the metal transferred with short circuit transfer?
When the filler wire is in direct contract with the base metal
If you dont know this check your phone
(DCEP) Direct Current Electrode Positive or Reverse polarity
AWS and CSA

10. What is the disadvantage of the gauge preset type of regulator/flowmeter?
Constant- speed wire feeders and Voltage- sennsing wire feeders
Increasing inductance increases puddle fluidity - improves penatration - makes the bead flatter and smoother - and reduces spatter. To much inductance though will create erratic starts
Minimum distortion due to low heat input
Generally not as accurate

11. What term is used to describe when the workpiece is hooked to the negative pole on the power source?
3
AWS and CSA
(DCEP) Direct Current Electrode Positive or Reverse polarity
Heat input is less than spray transfer - resulting in less distortion - Used in all positions due to controlling the weld metal freeze

12. Is the arc voltage for spray transfer higher or lower than that used for short circuit transfer?
Pressure - The rate of flow of a shielding gas
Cause flaking - which can clog the liner and contact tube
Dry ice can form within the flow control openings and cause blockage of shielding gas
Higher 26 to 35 arc volts

13. What does a flowmeter do and what does it measure?
Penetration and burn - off rate of the electrode
AWS and CSA
Controls the rate of flow of a shielding gas to the gun nozzle
...

14. Why is a fiber washer required and what cylinder gas requires it?
Aluminum wire
To prevent leakage - Carbon Dioxide (CO2)
Higher 26 to 35 arc volts
Gives arc voltage values to the control system of the feeder

15. List 3 wire drive systems and give a short description of each
85%
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- speed wire feeders and Voltage- sennsing wire feeders
When the filler wire is in direct contract with the base metal

16. What is the key advantage of short circuiting transfer?
Constant voltage (CV)
Aluminum wire
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

17. A 10 minute cycle of welding time vs cooling time a given machine can handle.
Motor driven generators - Transformer rectifiers - and Inverter designs
Duty cycle
Gives arc voltage values to the control system of the feeder
Cause flaking - which can clog the liner and contact tube

18. What is the maximum distance that hard wire can be successfully pushed?
15 feet (4.5 meters)
Wire feed speed - Voltage control
The negative side of a welding unit
To prevent leakage - Carbon Dioxide (CO2)

19. How many times per second does short circuiting take place?
20 to 200 times per second
Electricaly operated valves that control the flow of shielding gas to the weld zone. The control switch located on the gun
Minimum distortion due to low heat input
The resistace to electrical current flow increases with it. Causing the electrode to heat

20. What type of power source is used with a constant speed wire feeder?
Constant voltage (CV)
Voltage is the force that overcomes resistance to allow amperage flow
To limit the short circuiting current so that spatter is reduced
Penetration and burn - off rate of the electrode

21. What does the wire feeder 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
To limit the short circuiting current so that spatter is reduced
Speed of the feed motor and - starting / stopping electrode feed
Electricaly operated valves that control the flow of shielding gas to the weld zone. The control switch located on the gun

22. Draw a typical volt/amp curve that would be found with a power source designed for SMAW or GTAW
Welding Current - Filler wire diameter - arc length - type of shielding - position of the weld
Voltage is the force that overcomes resistance to allow amperage flow
If you dont know this check your phone
Duty cycle

23. What are the 2 types of wire feeders available?
Generally not as accurate
Constant- speed wire feeders and Voltage- sennsing wire feeders
Wire feed speed
Minimum distortion due to low heat input

24. What effect does increasing and decreasing the inductance have on the weld?
Minimum distortion due to low heat input
AWS and CSA
Increasing inductance increases puddle fluidity - improves penatration - makes the bead flatter and smoother - and reduces spatter. To much inductance though will create erratic starts
The resistace to electrical current flow increases with it. Causing the electrode to heat

25. In the GMAW process what does amperage control?
Penetration and burn - off rate of the electrode
AWS and CSA
DCEP (Direct Current Electrode Positive) Reverse Polarity
Increasing inductance increases puddle fluidity - improves penatration - makes the bead flatter and smoother - and reduces spatter. To much inductance though will create erratic starts

26. What output on the welding machine is used to rate the duty cycle?
Minimum distortion due to low heat input
15 feet (4.5 meters)
Minutes of elapsed time continually run (out of 10 minutes)
Welding Current - Filler wire diameter - arc length - type of shielding - position of the weld

27. How are GMAW guns rated?
1/4 inch to 1/2 inch
To prevent drawing of liquid CO2 (Carbon Dioxide)
Power source - wire feeder - welding gun - Spooled filler wire - Shielding gas - and a ground
By there current carrying capacity

28. What is the minimum % value of argon that must be present to use the spray transfer method of GMAW?
85%
Speed of the feed motor and - starting / stopping electrode feed
Constant voltage (CV)
Cause flaking - which can clog the liner and contact tube

29. What is the recommended electrode stick- out for .035 solid wire?
Aluminum wire
1/4 inch to 1/2 inch
Speed of the feed motor and - starting / stopping electrode feed
Pressure - The rate of flow of a shielding gas

30. What is the required arc voltage used for short circuit transfer?
If you dont know this check your phone
Constant- speed wire feeders and Voltage- sennsing wire feeders
12 to 22 arc volts
Constant voltage (CV)

31. What wire are knurled drive rolls most commonly used on?
...
85%
Flux cored wires
Aluminum wire

32. List the basic equipment requirements for the GMAW process
Power source - wire feeder - welding gun - Spooled filler wire - Shielding gas - and a ground
These terms are quite restrictive and often technically incorrect
20 to 200 times per second
The negative side of a welding unit

33. What current and polarity is generally used with GMAW?
DCEP (Direct Current Electrode Positive) Reverse Polarity
Speed of the feed motor and - starting / stopping electrode feed
To prevent leakage - Carbon Dioxide (CO2)
Welding process that joins metals by heating them with an electric arc

34. Draw a typical volt amp curve for a machine that is designed for GMAW
5.8 to 12.5 L/min
Power source - wire feeder - welding gun - Spooled filler wire - Shielding gas - and a ground
Constant- speed wire feeders and Voltage- sennsing wire feeders
If you dont know this check your phone

35. What is another term for electrode holders for GMAW?
Molten metal is separated from the end of the filler wire by a squeezing force created by a magnetic field
Guns
Voltage is the force that overcomes resistance to allow amperage flow
Heat input is less than spray transfer - resulting in less distortion - Used in all positions due to controlling the weld metal freeze

36. What happens when the electrode extension is increased?
The resistace to electrical current flow increases with it. Causing the electrode to heat
...
Duty cycle
Higher 26 to 35 arc volts

37. What is the preferred drive roll design for solid wires?
The time rate of response for the current rise and fall
V groove or U groove
Constant- speed wire feeders and Voltage- sennsing wire feeders
The Arc voltage

38. List 3 forms compressed gases may be supplied for welding
Compressed gas cylinder - Liquid filled cylinder - or a Liquid bulk system
Controls the rate of flow of a shielding gas to the gun nozzle
National Electrical Manufactures Association
Voltage is the force that overcomes resistance to allow amperage flow

39. What is the main purpose of 'slope'?
AWS and CSA
The resistace to electrical current flow increases with it. Causing the electrode to heat
If you dont know this check your phone
To limit the short circuiting current so that spatter is reduced

40. What does voltage do in an electrical circuit?
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
...
Voltage is the force that overcomes resistance to allow amperage flow
Flux cored wires

41. What type of power source is commonly used with a voltage sensing wire feeder?
(DCEP) Direct Current Electrode Positive or Reverse polarity
85%
Constant current (CC)
Minimum distortion due to low heat input

42. Why is the term GMAW preferred over MIG or MAG?
Constant current (CC)
Higher 26 to 35 arc volts
Cause flaking - which can clog the liner and contact tube
These terms are quite restrictive and often technically incorrect

43. List several industries that would use GMAW
Electricaly operated valves that control the flow of shielding gas to the weld zone. The control switch located on the gun
Pressure vessels and the piping industry
AWS and CSA
If you dont know this check your phone

44. What is the reason glass 'tube' type flowmeters must have the tube mounted truly vertical?
12 to 22 arc volts
Welding process that joins metals by heating them with an electric arc
Aluminum wire
...

45. When using flat drive rolls with too much pressure on copper coated solid wires what problem could take place?
Generally not as accurate
SMAW - GTAW
Controls the rate of flow of a shielding gas to the gun nozzle
Cause flaking - which can clog the liner and contact tube

46. In the GMAW process what does voltage control?
The time rate of response for the current rise and fall
Puddle fluidity
85%
If you dont know this check your phone

47. What is the purpose of the pick- up lead on a voltage sensing wire feeder?
Welding process that joins metals by heating them with an electric arc
Molten metal is separated from the end of the filler wire by a squeezing force created by a magnetic field
Gives arc voltage values to the control system of the feeder
When the filler wire is in direct contract with the base metal

48. A machine with a 70% duty cycle can run at its max for 7 minutes with a cooling cycle of only _ minutes.
3
Welding process that joins metals by heating them with an electric arc
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

49. Why is globular transfer generally avoided with GMAW?
SMAW - GTAW
Spatter problems and poor weld appearance
85%
Insufficient current to melt the wire off cleanly

50. Regulators control_____________ flowmeters SHOW____________.
Reducing the gas source pressure to a constant working pressure
Constant current (CC)
15 feet (4.5 meters)
Pressure - The rate of flow of a shielding gas