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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 the term GMAW preferred over MIG or MAG?
To limit the short circuiting current so that spatter is reduced
To prevent drawing of liquid CO2 (Carbon Dioxide)
...
These terms are quite restrictive and often technically incorrect

2. What controls the wire speed on a voltage sensing wire feeder?
Duty cycle
3
The Arc voltage
If you dont know this check your phone

3. What is a typical flow rate of CO2 for short circuit transfer?
Guns
5.8 to 12.5 L/min
Welding process that joins metals by heating them with an electric arc
Duty cycle

4. What does the wire feeder control?
Speed of the feed motor and - starting / stopping electrode feed
1/4 inch to 1/2 inch
Constant voltage (CV)
Pressure vessels and the piping industry

5. List the three methods of metal transfer with GMAW
Wire feed speed - Voltage control
1/4 inch to 1/2 inch
85%
Short- circuiting transfer - Globular transfer - Spray transfer

6. What happens when the electrode extension is increased?
Constant current (CC)
Minimum distortion due to low heat input
The resistace to electrical current flow increases with it. Causing the electrode to heat
Gas metal arc welding

7. What output on the welding machine is used to rate the duty cycle?
Minutes of elapsed time continually run (out of 10 minutes)
By there current carrying capacity
DCEP (Direct Current Electrode Positive) Reverse Polarity
To prevent drawing of liquid CO2 (Carbon Dioxide)

8. What would be an indication that the drive roll pressure is adjusted correctly?
Controls the rate of flow of a shielding gas to the gun nozzle
Wire feeds smoothly (yet will slip should a problem occur in the gun)
SMAW - GTAW
Generally not as accurate

9. List several industries that would use GMAW
Pressure vessels and the piping industry
Increasing inductance increases puddle fluidity - improves penatration - makes the bead flatter and smoother - and reduces spatter. To much inductance though will create erratic starts
Electricaly operated valves that control the flow of shielding gas to the weld zone. The control switch located on the gun
Constant- speed wire feeders and Voltage- sennsing wire feeders

10. What are the 2 types of wire feeders available?
The resistace to electrical current flow increases with it. Causing the electrode to heat
Constant- speed wire feeders and Voltage- sennsing wire feeders
Gives arc voltage values to the control system of the feeder
Shielding the molten weld metal from atmospheric contamination

11. What type of power source is used with a constant speed wire feeder?
85%
Constant voltage (CV)
...
Gives arc voltage values to the control system of the feeder

12. How are GMAW guns rated?
Minimum distortion due to low heat input
If you dont know this check your phone
By there current carrying capacity
Molten metal is separated from the end of the filler wire by a squeezing force created by a magnetic field

13. 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
If you dont know this check your phone
Motor driven generators - Transformer rectifiers - and Inverter designs

14. What is the main purpose of 'slope'?
Short- circuiting transfer - Globular transfer - Spray transfer
Welding Current - Filler wire diameter - arc length - type of shielding - position of the weld
Higher 26 to 35 arc volts
To limit the short circuiting current so that spatter is reduced

15. What 2 organizations designate specifications for GMAW wires?
National Electrical Manufactures Association
AWS and CSA
Minimum distortion due to low heat input
Minutes of elapsed time continually run (out of 10 minutes)

16. A machine with a 70% duty cycle can run at its max for 7 minutes with a cooling cycle of only _ minutes.
By there current carrying capacity
The negative side of a welding unit
To limit the short circuiting current so that spatter is reduced
3

17. What is the maximum distance that hard wire can be successfully pushed?
Pressure vessels and the piping industry
15 feet (4.5 meters)
To limit the short circuiting current so that spatter is reduced
Flux cored wires

18. What is the purpose of the pick- up lead on a voltage sensing wire feeder?
The Arc voltage
Gives arc voltage values to the control system of the feeder
Welding Current - Filler wire diameter - arc length - type of shielding - position of the weld
The negative side of a welding unit

19. List the factors that determine the mode of metal transfer
Wire feed speed
Welding Current - Filler wire diameter - arc length - type of shielding - position of the weld
Insufficient current to melt the wire off cleanly
Minutes of elapsed time continually run (out of 10 minutes)

20. What is an advantage of pulsed arc transfer with GMAW?
15 feet (4.5 meters)
Heat input is less than spray transfer - resulting in less distortion - Used in all positions due to controlling the weld metal freeze
3
Wire feed speed

21. What type of power source is commonly used with a voltage sensing wire feeder?
DCEP (Direct Current Electrode Positive) Reverse Polarity
Pressure vessels and the piping industry
Power source - wire feeder - welding gun - Spooled filler wire - Shielding gas - and a ground
Constant current (CC)

22. With straight polarity where is 2/3 of the arc energy?
The negative side of a welding unit
Welding Current - Filler wire diameter - arc length - type of shielding - position of the weld
Shielding the molten weld metal from atmospheric contamination
Speed of the feed motor and - starting / stopping electrode feed

23. What is the minimum % value of argon that must be present to use the spray transfer method of GMAW?
Constant current (CC)
If you dont know this check your phone
85%
5.8 to 12.5 L/min

24. A pull type drive system is usually used on what type of material?
Welding Current - Filler wire diameter - arc length - type of shielding - position of the weld
Aluminum wire
1/4 inch to 1/2 inch
The negative side of a welding unit

25. What does a flowmeter do and what does it measure?
Controls the rate of flow of a shielding gas to the gun nozzle
Constant voltage (CV)
Increasing inductance increases puddle fluidity - improves penatration - makes the bead flatter and smoother - and reduces spatter. To much inductance though will create erratic starts
If you dont know this check your phone

26. What is the purpose of the shielding gas used in GMAW?
Shielding the molten weld metal from atmospheric contamination
Aluminum wire
Puddle fluidity
National Electrical Manufactures Association

27. Why is a line heater required when using GMAW?
Dry ice can form within the flow control openings and cause blockage of shielding gas
Heat input is less than spray transfer - resulting in less distortion - Used in all positions due to controlling the weld metal freeze
Guns
Shielding the molten weld metal from atmospheric contamination

28. In the GMAW process what does voltage control?
Voltage is the force that overcomes resistance to allow amperage flow
Puddle fluidity
Controls the rate of flow of a shielding gas to the gun nozzle
Heat input is less than spray transfer - resulting in less distortion - Used in all positions due to controlling the weld metal freeze

29. What is the effect of too much slope?
Insufficient current to melt the wire off cleanly
Welding Current - Filler wire diameter - arc length - type of shielding - position of the weld
Penetration and burn - off rate of the electrode
85%

30. What 2 controls are found on a GMAW set- up?
Wire feed speed - Voltage control
These terms are quite restrictive and often technically incorrect
Pressure - The rate of flow of a shielding gas
The Arc voltage

31. What is another term for electrode holders for GMAW?
To prevent drawing of liquid CO2 (Carbon Dioxide)
Aluminum wire
Guns
V groove or U groove

32. In the GMAW process what does amperage control?
To prevent leakage - Carbon Dioxide (CO2)
Penetration and burn - off rate of the electrode
By there current carrying capacity
DCEP (Direct Current Electrode Positive) Reverse Polarity

33. What is the recommended electrode stick- out for .035 solid wire?
Controls the rate of flow of a shielding gas to the gun nozzle
1/4 inch to 1/2 inch
To prevent leakage - Carbon Dioxide (CO2)
Pressure - The rate of flow of a shielding gas

34. What controls amperage when using GMAW?
Wire feed speed
15 feet (4.5 meters)
Penetration and burn - off rate of the electrode
85%

35. Why must CO2 cylinders be used in the vertical position?
To limit the short circuiting current so that spatter is reduced
These terms are quite restrictive and often technically incorrect
To prevent drawing of liquid CO2 (Carbon Dioxide)
Puddle fluidity

36. Draw a typical volt amp curve for a machine that is designed for GMAW
National Electrical Manufactures Association
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
The resistace to electrical current flow increases with it. Causing the electrode to heat

37. List 3 wire drive systems and give a short description of each
5.8 to 12.5 L/min
Short- circuiting transfer - Globular transfer - Spray 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
Welding process that joins metals by heating them with an electric arc

38. List 3 forms compressed gases may be supplied for welding
Voltage is the force that overcomes resistance to allow amperage flow
The negative side of a welding unit
Spatter problems and poor weld appearance
Compressed gas cylinder - Liquid filled cylinder - or a Liquid bulk system

39. What is the purpose of a regulator and what does it indicate on its gauges?
When the filler wire is in direct contract with the base metal
Reducing the gas source pressure to a constant working pressure
5.8 to 12.5 L/min
(DCEP) Direct Current Electrode Positive or Reverse polarity

40. What power sources are used with the GMAW Process?
Pressure vessels and the piping industry
Spatter problems and poor weld appearance
If you dont know this check your phone
Motor driven generators - Transformer rectifiers - and Inverter designs

41. Why is globular transfer generally avoided with GMAW?
The negative side of a welding unit
Voltage is the force that overcomes resistance to allow amperage flow
Spatter problems and poor weld appearance
These terms are quite restrictive and often technically incorrect

42. What does inductance control?
Electricaly operated valves that control the flow of shielding gas to the weld zone. The control switch located on the gun
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
20 to 200 times per second
The time rate of response for the current rise and fall

43. A 10 minute cycle of welding time vs cooling time a given machine can handle.
Duty cycle
SMAW - GTAW
Increasing inductance increases puddle fluidity - improves penatration - makes the bead flatter and smoother - and reduces spatter. To much inductance though will create erratic starts
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

44. When using flat drive rolls with too much pressure on copper coated solid wires what problem could take place?
National Electrical Manufactures Association
20 to 200 times per second
Flux cored wires
Cause flaking - which can clog the liner and contact tube

45. What does the abbreviation NEMA stand for?
Wire feed speed
National Electrical Manufactures Association
Guns
Electricaly operated valves that control the flow of shielding gas to the weld zone. The control switch located on the gun

46. Give a brief description of the GMAW process
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
Welding process that joins metals by heating them with an electric arc
These terms are quite restrictive and often technically incorrect
Constant- speed wire feeders and Voltage- sennsing wire feeders

47. What is a solenoid valve and what actuates it?
Welding Current - Filler wire diameter - arc length - type of shielding - position of the weld
85%
SMAW - GTAW
Electricaly operated valves that control the flow of shielding gas to the weld zone. The control switch located on the gun

48. Regulators control_____________ flowmeters SHOW____________.
Voltage is the force that overcomes resistance to allow amperage flow
Welding process that joins metals by heating them with an electric arc
Minutes of elapsed time continually run (out of 10 minutes)
Pressure - The rate of flow of a shielding gas

49. What does the term GMAW identify?
Gas metal arc welding
Dry ice can form within the flow control openings and cause blockage of shielding gas
Welding process that joins metals by heating them with an electric arc
Flux cored wires

50. What is the preferred drive roll design for solid wires?
To prevent drawing of liquid CO2 (Carbon Dioxide)
V groove or U groove
Constant current (CC)
National Electrical Manufactures Association