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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 does a flowmeter do and what does it measure?
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
Speed of the feed motor and - starting / stopping electrode feed
Minimum distortion due to low heat input

2. Draw a typical volt amp curve for a machine that is designed for GMAW
By there current carrying capacity
Wire feed speed - Voltage control
15 feet (4.5 meters)
If you dont know this check your phone

3. Regulators control_____________ flowmeters SHOW____________.
DCEP (Direct Current Electrode Positive) Reverse Polarity
Pressure - The rate of flow of a shielding gas
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

4. When is the metal transferred with short circuit transfer?
When the filler wire is in direct contract with the base metal
20 to 200 times per second
Increasing inductance increases puddle fluidity - improves penatration - makes the bead flatter and smoother - and reduces spatter. To much inductance though will create erratic starts
Constant voltage (CV)

5. A 10 minute cycle of welding time vs cooling time a given machine can handle.
Constant- speed wire feeders and Voltage- sennsing wire feeders
Electricaly operated valves that control the flow of shielding gas to the weld zone. The control switch located on the gun
Duty cycle
Speed of the feed motor and - starting / stopping electrode feed

6. What is the required arc voltage used for short circuit transfer?
12 to 22 arc volts
Welding process that joins metals by heating them with an electric arc
20 to 200 times per second
Gives arc voltage values to the control system of the feeder

7. What controls amperage when using GMAW?
Wire feed speed
Constant voltage (CV)
Insufficient current to melt the wire off cleanly
Wire feeds smoothly (yet will slip should a problem occur in the gun)

8. 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
To limit the short circuiting current so that spatter is reduced
Cause flaking - which can clog the liner and contact tube
Controls the rate of flow of a shielding gas to the gun nozzle

9. What type of power source is used with a constant speed wire feeder?
Power source - wire feeder - welding gun - Spooled filler wire - Shielding gas - and a ground
Minutes of elapsed time continually run (out of 10 minutes)
Constant voltage (CV)
Higher 26 to 35 arc volts

10. When using flat drive rolls with too much pressure on copper coated solid wires what problem could take place?
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
1/4 inch to 1/2 inch
Cause flaking - which can clog the liner and contact tube

11. How are GMAW guns rated?
Aluminum wire
By there current carrying capacity
Constant voltage (CV)
National Electrical Manufactures Association

12. Give a brief description of the GMAW process
Minutes of elapsed time continually run (out of 10 minutes)
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
Wire feeds smoothly (yet will slip should a problem occur in the gun)

13. What 2 organizations designate specifications for GMAW wires?
Heat input is less than spray transfer - resulting in less distortion - Used in all positions due to controlling the weld metal freeze
Penetration and burn - off rate of the electrode
AWS and CSA
The time rate of response for the current rise and fall

14. What is the main purpose of 'slope'?
Spatter problems and poor weld appearance
5.8 to 12.5 L/min
To limit the short circuiting current so that spatter is reduced
Pressure vessels and the piping industry

15. Is the arc voltage for spray transfer higher or lower than that used for short circuit transfer?
Guns
Higher 26 to 35 arc volts
When the filler wire is in direct contract with the base metal
The resistace to electrical current flow increases with it. Causing the electrode to heat

16. What does the term GMAW identify?
Penetration and burn - off rate of the electrode
Higher 26 to 35 arc volts
Gas metal arc welding
(DCEP) Direct Current Electrode Positive or Reverse polarity

17. What effect does increasing and decreasing the inductance have on the weld?
Generally not as accurate
The negative side of a welding unit
Increasing inductance increases puddle fluidity - improves penatration - makes the bead flatter and smoother - and reduces spatter. To much inductance though will create erratic starts
Molten metal is separated from the end of the filler wire by a squeezing force created by a magnetic field

18. What is the maximum distance that hard wire can be successfully pushed?
Minimum distortion due to low heat input
15 feet (4.5 meters)
Wire feed speed - Voltage control
Increasing inductance increases puddle fluidity - improves penatration - makes the bead flatter and smoother - and reduces spatter. To much inductance though will create erratic starts

19. What is the minimum % value of argon that must be present to use the spray transfer method of GMAW?
Wire feed speed
85%
Power source - wire feeder - welding gun - Spooled filler wire - Shielding gas - and a ground
Constant voltage (CV)

20. What is the reason glass 'tube' type flowmeters must have the tube mounted truly vertical?
15 feet (4.5 meters)
...
The resistace to electrical current flow increases with it. Causing the electrode to heat
Wire feed speed

21. What wire are knurled drive rolls most commonly used on?
Gives arc voltage values to the control system of the feeder
Controls the rate of flow of a shielding gas to the gun nozzle
Flux cored wires
Pressure vessels and the piping industry

22. List 3 forms compressed gases may be supplied for welding
Compressed gas cylinder - Liquid filled cylinder - or a Liquid bulk system
The negative side of a welding unit
To prevent drawing of liquid CO2 (Carbon Dioxide)
Shielding the molten weld metal from atmospheric contamination

23. What is the effect of too much slope?
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
Insufficient current to melt the wire off cleanly
If you dont know this check your phone
Wire feed speed

24. What does the wire feeder control?
Motor driven generators - Transformer rectifiers - and Inverter designs
To prevent drawing of liquid CO2 (Carbon Dioxide)
Molten metal is separated from the end of the filler wire by a squeezing force created by a magnetic field
Speed of the feed motor and - starting / stopping electrode feed

25. What is the recommended electrode stick- out for .035 solid wire?
1/4 inch to 1/2 inch
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
Wire feed speed

26. A machine with a 70% duty cycle can run at its max for 7 minutes with a cooling cycle of only _ minutes.
Generally not as accurate
3
Short- circuiting transfer - Globular transfer - Spray transfer
85%

27. List the factors that determine the mode of metal transfer
National Electrical Manufactures Association
Welding Current - Filler wire diameter - arc length - type of shielding - position of the weld
20 to 200 times per second
Increasing inductance increases puddle fluidity - improves penatration - makes the bead flatter and smoother - and reduces spatter. To much inductance though will create erratic starts

28. What power sources are used with 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
National Electrical Manufactures Association
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

29. In the GMAW process what does voltage control?
Heat input is less than spray transfer - resulting in less distortion - Used in all positions due to controlling the weld metal freeze
Constant voltage (CV)
Puddle fluidity
Penetration and burn - off rate of the electrode

30. What is the purpose of a regulator and what does it indicate on its gauges?
3
Compressed gas cylinder - Liquid filled cylinder - or a Liquid bulk system
Reducing the gas source pressure to a constant working pressure
V groove or U groove

31. What are the 2 types of wire feeders available?
1/4 inch to 1/2 inch
Constant- speed wire feeders and Voltage- sennsing wire feeders
Gives arc voltage values to the control system of the feeder
Constant voltage (CV)

32. What processes are constant current (CC) power sources designed to be used with?
85%
(DCEP) Direct Current Electrode Positive or Reverse polarity
SMAW - GTAW
Aluminum wire

33. Draw a typical volt/amp curve that would be found with a power source designed for SMAW or GTAW
Constant- speed wire feeders and Voltage- sennsing wire feeders
To prevent drawing of liquid CO2 (Carbon Dioxide)
If you dont know this check your phone
15 feet (4.5 meters)

34. Why is the term GMAW preferred over MIG or MAG?
Aluminum wire
Gas metal arc welding
These terms are quite restrictive and often technically incorrect
15 feet (4.5 meters)

35. What current and polarity is generally used with GMAW?
Spatter problems and poor weld appearance
Minimum distortion due to low heat input
85%
DCEP (Direct Current Electrode Positive) Reverse Polarity

36. Why is globular transfer generally avoided with GMAW?
Spatter problems and poor weld appearance
20 to 200 times per second
Duty cycle
To prevent drawing of liquid CO2 (Carbon Dioxide)

37. List the basic equipment requirements for the GMAW process
Cause flaking - which can clog the liner and contact tube
(DCEP) Direct Current Electrode Positive or Reverse polarity
Pressure vessels and the piping industry
Power source - wire feeder - welding gun - Spooled filler wire - Shielding gas - and a ground

38. What does the abbreviation NEMA stand for?
National Electrical Manufactures Association
Higher 26 to 35 arc volts
Wire feed speed
Pressure vessels and the piping industry

39. What 2 controls are found on a GMAW set- up?
Constant current (CC)
Shielding the molten weld metal from atmospheric contamination
Wire feed speed - Voltage control
If you dont know this check your phone

40. What happens when the electrode extension is increased?
85%
Higher 26 to 35 arc volts
The resistace to electrical current flow increases with it. Causing the electrode to heat
Insufficient current to melt the wire off cleanly

41. Why is a fiber washer required and what cylinder gas requires it?
Minimum distortion due to low heat input
Pressure - The rate of flow of a shielding gas
To prevent leakage - Carbon Dioxide (CO2)
1/4 inch to 1/2 inch

42. What is another term for electrode holders for GMAW?
AWS and CSA
Motor driven generators - Transformer rectifiers - and Inverter designs
Guns
12 to 22 arc volts

43. What is a typical flow rate of CO2 for short circuit transfer?
15 feet (4.5 meters)
When the filler wire is in direct contract with the base metal
5.8 to 12.5 L/min
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. What term is used to describe when the workpiece is hooked to the negative pole on the power source?
Heat input is less than spray transfer - resulting in less distortion - Used in all positions due to controlling the weld metal freeze
(DCEP) Direct Current Electrode Positive or Reverse polarity
Higher 26 to 35 arc volts
Insufficient current to melt the wire off cleanly

45. List the three methods of metal transfer with GMAW
Constant current (CC)
Short- circuiting transfer - Globular transfer - Spray transfer
V groove or U groove
85%

46. List 3 wire drive systems and give a short description of each
To prevent drawing of liquid CO2 (Carbon Dioxide)
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
15 feet (4.5 meters)
Wire feed speed

47. A pull type drive system is usually used on what type of material?
Controls the rate of flow of a shielding gas to the gun nozzle
Aluminum wire
Minimum distortion due to low heat input
V groove or U groove

48. What is the preferred drive roll design for solid wires?
V groove or U groove
Duty cycle
Generally not as accurate
If you dont know this check your phone

49. Why is a line heater required when using GMAW?
20 to 200 times per second
Dry ice can form within the flow control openings and cause blockage of shielding gas
12 to 22 arc volts
Wire feed speed

50. What controls the wire speed on a voltage sensing wire feeder?
Reducing the gas source pressure to a constant working pressure
The Arc voltage
Dry ice can form within the flow control openings and cause blockage of shielding gas
Controls the rate of flow of a shielding gas to the gun nozzle