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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. How are GMAW guns rated?
Constant current (CC)
By there current carrying capacity
20 to 200 times per second
These terms are quite restrictive and often technically incorrect

2. What 2 organizations designate specifications for GMAW wires?
AWS and CSA
Voltage is the force that overcomes resistance to allow amperage flow
Minutes of elapsed time continually run (out of 10 minutes)
If you dont know this check your phone

3. What does the abbreviation NEMA stand for?
Constant current (CC)
Generally not as accurate
National Electrical Manufactures Association
Penetration and burn - off rate of the electrode

4. List the factors that determine the mode of metal transfer
Welding Current - Filler wire diameter - arc length - type of shielding - position of the weld
Wire feed speed
Spatter problems and poor weld appearance
The time rate of response for the current rise and fall

5. What type of power source is commonly used with a voltage sensing wire feeder?
Heat input is less than spray transfer - resulting in less distortion - Used in all positions due to controlling the weld metal freeze
Constant current (CC)
1/4 inch to 1/2 inch
Puddle fluidity

6. How many times per second does short circuiting take place?
Generally not as accurate
Motor driven generators - Transformer rectifiers - and Inverter designs
20 to 200 times per second
Duty cycle

7. What would be an indication that the drive roll pressure is adjusted correctly?
Generally not as accurate
Constant voltage (CV)
Wire feeds smoothly (yet will slip should a problem occur in the gun)
Flux cored wires

8. What current and polarity is generally used with GMAW?
DCEP (Direct Current Electrode Positive) Reverse Polarity
85%
Power source - wire feeder - welding gun - Spooled filler wire - Shielding gas - and a ground
Pressure - The rate of flow of a shielding gas

9. What is the disadvantage of the gauge preset type of regulator/flowmeter?
(DCEP) Direct Current Electrode Positive or Reverse polarity
1/4 inch to 1/2 inch
Short- circuiting transfer - Globular transfer - Spray transfer
Generally not as accurate

10. A machine with a 70% duty cycle can run at its max for 7 minutes with a cooling cycle of only _ minutes.
Voltage is the force that overcomes resistance to allow amperage flow
Dry ice can form within the flow control openings and cause blockage of shielding gas
3
Welding process that joins metals by heating them with an electric arc

11. What type of power source is used with a constant speed wire 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)
20 to 200 times per second
Power source - wire feeder - welding gun - Spooled filler wire - Shielding gas - and a ground

12. What term is used to describe when the workpiece is hooked to the negative pole on the power source?
Welding Current - Filler wire diameter - arc length - type of shielding - position of the weld
If you dont know this check your phone
...
(DCEP) Direct Current Electrode Positive or Reverse polarity

13. In the GMAW process what does amperage control?
Welding Current - Filler wire diameter - arc length - type of shielding - position of the weld
These terms are quite restrictive and often technically incorrect
5.8 to 12.5 L/min
Penetration and burn - off rate of the electrode

14. Draw a typical volt amp curve for a machine that is designed for GMAW
Speed of the feed motor and - starting / stopping electrode feed
If you dont know this check your phone
When the filler wire is in direct contract with the base metal
Welding Current - Filler wire diameter - arc length - type of shielding - position of the weld

15. What are the 2 types of wire feeders available?
Wire feeds smoothly (yet will slip should a problem occur in the gun)
Constant- speed wire feeders and Voltage- sennsing wire feeders
Gas metal arc welding
The time rate of response for the current rise and fall

16. What is the maximum distance that hard wire can be successfully pushed?
Molten metal is separated from the end of the filler wire by a squeezing force created by a magnetic field
Insufficient current to melt the wire off cleanly
15 feet (4.5 meters)
Penetration and burn - off rate of the electrode

17. What is an advantage of pulsed arc transfer with GMAW?
Welding process that joins metals by heating them with an electric arc
Heat input is less than spray transfer - resulting in less distortion - Used in all positions due to controlling the weld metal freeze
These terms are quite restrictive and often technically incorrect
85%

18. What is the minimum % value of argon that must be present to use the spray transfer method of GMAW?
National Electrical Manufactures Association
85%
Wire feed speed - Voltage control
Higher 26 to 35 arc volts

19. Why is globular transfer generally avoided with GMAW?
Speed of the feed motor and - starting / stopping electrode feed
Spatter problems and poor weld appearance
Voltage is the force that overcomes resistance to allow amperage flow
When the filler wire is in direct contract with the base metal

20. What processes are constant current (CC) power sources designed to be used with?
Welding Current - Filler wire diameter - arc length - type of shielding - position of the weld
Gas metal arc welding
SMAW - GTAW
Aluminum wire

21. List 3 wire drive systems and give a short description of each
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
Shielding the molten weld metal from atmospheric contamination
Wire feed speed
Electricaly operated valves that control the flow of shielding gas to the weld zone. The control switch located on the gun

22. What happens when the electrode extension is increased?
Controls the rate of flow of a shielding gas to the gun nozzle
Compressed gas cylinder - Liquid filled cylinder - or a Liquid bulk system
The resistace to electrical current flow increases with it. Causing the electrode to heat
...

23. What is a solenoid valve and what actuates it?
V groove or U groove
Electricaly operated valves that control the flow of shielding gas to the weld zone. The control switch located on the gun
By there current carrying capacity
Welding process that joins metals by heating them with an electric arc

24. What is the purpose of a regulator and what does it indicate on its gauges?
These terms are quite restrictive and often technically incorrect
Reducing the gas source pressure to a constant working pressure
Power source - wire feeder - welding gun - Spooled filler wire - Shielding gas - and a ground
12 to 22 arc volts

25. What controls amperage when using GMAW?
Guns
Wire feed speed
Gas metal arc welding
Controls the rate of flow of a shielding gas to the gun nozzle

26. Why is a fiber washer required and what cylinder gas requires it?
Short- circuiting transfer - Globular transfer - Spray transfer
To prevent leakage - Carbon Dioxide (CO2)
Higher 26 to 35 arc volts
DCEP (Direct Current Electrode Positive) Reverse Polarity

27. What output on the welding machine is used to rate the duty cycle?
Minutes of elapsed time continually run (out of 10 minutes)
If you dont know this check your phone
V groove or U groove
5.8 to 12.5 L/min

28. A pull type drive system is usually used on what type of material?
The Arc voltage
Controls the rate of flow of a shielding gas to the gun nozzle
Aluminum wire
Power source - wire feeder - welding gun - Spooled filler wire - Shielding gas - and a ground

29. With straight polarity where is 2/3 of the arc energy?
Constant voltage (CV)
Guns
The negative side of a welding unit
Higher 26 to 35 arc volts

30. What is the purpose of the pick- up lead on a voltage sensing wire feeder?
Constant voltage (CV)
Gives arc voltage values to the control system of the feeder
To prevent drawing of liquid CO2 (Carbon Dioxide)
These terms are quite restrictive and often technically incorrect

31. What is the recommended electrode stick- out for .035 solid wire?
By there current carrying capacity
Minimum distortion due to low heat input
85%
1/4 inch to 1/2 inch

32. Is the arc voltage for spray transfer higher or lower than that used 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
Controls the rate of flow of a shielding gas to the gun nozzle
...
Higher 26 to 35 arc volts

33. Draw a typical volt/amp curve that would be found with a power source designed for SMAW or GTAW
Aluminum wire
Reducing the gas source pressure to a constant working pressure
By there current carrying capacity
If you dont know this check your phone

34. What is the reason glass 'tube' type flowmeters must have the tube mounted truly vertical?
SMAW - GTAW
...
The time rate of response for the current rise and fall
Power source - wire feeder - welding gun - Spooled filler wire - Shielding gas - and a ground

35. A 10 minute cycle of welding time vs cooling time a given machine can handle.
3
Electricaly operated valves that control the flow of shielding gas to the weld zone. The control switch located on the gun
If you dont know this check your phone
Duty cycle

36. What is the preferred drive roll design for solid wires?
These terms are quite restrictive and often technically incorrect
Dry ice can form within the flow control openings and cause blockage of shielding gas
V groove or U groove
Gas metal arc welding

37. What does voltage do in an electrical circuit?
85%
Wire feeds smoothly (yet will slip should a problem occur in the gun)
Voltage is the force that overcomes resistance to allow amperage flow
Pressure - The rate of flow of a shielding gas

38. What wire are knurled drive rolls most commonly used on?
The time rate of response for the current rise and fall
(DCEP) Direct Current Electrode Positive or Reverse polarity
Motor driven generators - Transformer rectifiers - and Inverter designs
Flux cored wires

39. What does a flowmeter do and what does it measure?
Duty cycle
Reducing the gas source pressure to a constant working pressure
Power source - wire feeder - welding gun - Spooled filler wire - Shielding gas - and a ground
Controls the rate of flow of a shielding gas to the gun nozzle

40. List the three methods of metal transfer with GMAW
1/4 inch to 1/2 inch
To prevent drawing of liquid CO2 (Carbon Dioxide)
Short- circuiting transfer - Globular transfer - Spray transfer
V groove or U groove

41. List the basic equipment requirements for the GMAW process
If you dont know this check your phone
Duty cycle
V groove or U groove
Power source - wire feeder - welding gun - Spooled filler wire - Shielding gas - and a ground

42. What is a typical flow rate of CO2 for short circuit transfer?
Power source - wire feeder - welding gun - Spooled filler wire - Shielding gas - and a ground
5.8 to 12.5 L/min
1/4 inch to 1/2 inch
12 to 22 arc volts

43. What does the wire feeder control?
Molten metal is separated from the end of the filler wire by a squeezing force created by a magnetic field
15 feet (4.5 meters)
The negative side of a welding unit
Speed of the feed motor and - starting / stopping electrode feed

44. What power sources are used with the GMAW Process?
Pressure - The rate of flow of a shielding gas
Aluminum wire
Motor driven generators - Transformer rectifiers - and Inverter designs
The negative side of a welding unit

45. Why is the term GMAW preferred over MIG or MAG?
To prevent leakage - Carbon Dioxide (CO2)
Spatter problems and poor weld appearance
These terms are quite restrictive and often technically incorrect
Wire feed speed

46. Regulators control_____________ flowmeters SHOW____________.
Shielding the molten weld metal from atmospheric contamination
Constant voltage (CV)
The resistace to electrical current flow increases with it. Causing the electrode to heat
Pressure - The rate of flow of a shielding gas

47. What is the key advantage of short circuiting transfer?
Minimum distortion due to low heat input
Pressure - The rate of flow of a shielding gas
AWS and CSA
The resistace to electrical current flow increases with it. Causing the electrode to heat

48. What effect does increasing and decreasing the inductance have on the weld?
Duty cycle
Motor driven generators - Transformer rectifiers - and Inverter designs
Power source - wire feeder - welding gun - Spooled filler wire - Shielding gas - and a ground
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. What is the effect of too much slope?
Insufficient current to melt the wire off cleanly
Power source - wire feeder - welding gun - Spooled filler wire - Shielding gas - and a ground
DCEP (Direct Current Electrode Positive) Reverse Polarity
By there current carrying capacity

50. Give a brief description of the GMAW process
Insufficient current to melt the wire off cleanly
...
Generally not as accurate
Welding process that joins metals by heating them with an electric arc