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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 the reason glass 'tube' type flowmeters must have the tube mounted truly vertical?
The time rate of response for the current rise and fall
Reducing the gas source pressure to a constant working pressure
...
The resistace to electrical current flow increases with it. Causing the electrode to heat

2. When is the metal transferred with short circuit transfer?
When the filler wire is in direct contract with the base metal
These terms are quite restrictive and often technically incorrect
Higher 26 to 35 arc volts
Pressure - The rate of flow of a shielding gas

3. What is the purpose of the pick- up lead on a voltage sensing wire feeder?
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
1/4 inch to 1/2 inch
Gives arc voltage values to the control system of the feeder

4. Draw a typical volt amp curve for a machine that is designed for GMAW
To prevent leakage - Carbon Dioxide (CO2)
If you dont know this check your phone
The Arc voltage
Constant- speed wire feeders and Voltage- sennsing wire feeders

5. What does the abbreviation NEMA stand for?
AWS and CSA
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

6. What controls the wire speed on a voltage sensing wire feeder?
Penetration and burn - off rate of the electrode
The Arc voltage
15 feet (4.5 meters)
Voltage is the force that overcomes resistance to allow amperage flow

7. What type of power source is commonly used with a voltage sensing wire feeder?
Pressure vessels and the piping industry
Gives arc voltage values to the control system of the feeder
DCEP (Direct Current Electrode Positive) Reverse Polarity
Constant current (CC)

8. What processes are constant current (CC) power sources designed to be used with?
Increasing inductance increases puddle fluidity - improves penatration - makes the bead flatter and smoother - and reduces spatter. To much inductance though will create erratic starts
(DCEP) Direct Current Electrode Positive or Reverse polarity
Penetration and burn - off rate of the electrode
SMAW - GTAW

9. A machine with a 70% duty cycle can run at its max for 7 minutes with a cooling cycle of only _ minutes.
Molten metal is separated from the end of the filler wire by a squeezing force created by a magnetic field
3
1/4 inch to 1/2 inch
DCEP (Direct Current Electrode Positive) Reverse Polarity

10. Give a brief description of the GMAW process
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
Welding process that joins metals by heating them with an electric arc
85%

11. Why is the term GMAW preferred over MIG or MAG?
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
The negative side of a welding unit
15 feet (4.5 meters)

12. What is a solenoid valve and what actuates it?
Minimum distortion due to low heat input
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
Shielding the molten weld metal from atmospheric contamination

13. What is the effect of too much slope?
Welding process that joins metals by heating them with an electric arc
AWS and CSA
Pressure - The rate of flow of a shielding gas
Insufficient current to melt the wire off cleanly

14. How are GMAW guns rated?
Penetration and burn - off rate of the electrode
By there current carrying capacity
Pressure - The rate of flow of a shielding gas
Minutes of elapsed time continually run (out of 10 minutes)

15. List 3 wire drive systems and give a short description of each
Reducing the gas source pressure to a constant working pressure
Duty cycle
(DCEP) Direct Current Electrode Positive or Reverse polarity
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

16. List the factors that determine the mode of metal transfer
Spatter problems and poor weld appearance
National Electrical Manufactures Association
V groove or U groove
Welding Current - Filler wire diameter - arc length - type of shielding - position of the weld

17. List 3 forms compressed gases may be supplied for welding
Wire feed speed - Voltage control
Welding process that joins metals by heating them with an electric arc
Compressed gas cylinder - Liquid filled cylinder - or a Liquid bulk system
Gives arc voltage values to the control system of the feeder

18. What is an advantage of pulsed arc transfer with GMAW?
The time rate of response for the current rise and fall
Heat input is less than spray transfer - resulting in less distortion - Used in all positions due to controlling the weld metal freeze
By there current carrying capacity
When the filler wire is in direct contract with the base metal

19. List the basic equipment requirements for the GMAW process
Welding Current - Filler wire diameter - arc length - type of shielding - position of the weld
Heat input is less than spray transfer - resulting in less distortion - Used in all positions due to controlling the weld metal freeze
Power source - wire feeder - welding gun - Spooled filler wire - Shielding gas - and a ground
When the filler wire is in direct contract with the base metal

20. What is the preferred drive roll design for solid wires?
V groove or U groove
Welding Current - Filler wire diameter - arc length - type of shielding - position of the weld
National Electrical Manufactures Association
Voltage is the force that overcomes resistance to allow amperage flow

21. Why is a line heater required when using GMAW?
Dry ice can form within the flow control openings and cause blockage of shielding gas
Guns
National Electrical Manufactures Association
SMAW - GTAW

22. 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
Short- circuiting transfer - Globular transfer - Spray transfer
Minimum distortion due to low heat input
Reducing the gas source pressure to a constant working pressure

23. What 2 controls are found on a GMAW set- up?
SMAW - GTAW
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
Wire feed speed - Voltage control

24. Why is globular transfer generally avoided with GMAW?
Spatter problems and poor weld appearance
Speed of the feed motor and - starting / stopping electrode feed
12 to 22 arc volts
Heat input is less than spray transfer - resulting in less distortion - Used in all positions due to controlling the weld metal freeze

25. What is the key advantage of short circuiting transfer?
1/4 inch to 1/2 inch
If you dont know this check your phone
Minimum distortion due to low heat input
Pressure vessels and the piping industry

26. What is the recommended electrode stick- out for .035 solid wire?
Power source - wire feeder - welding gun - Spooled filler wire - Shielding gas - and a ground
1/4 inch to 1/2 inch
Motor driven generators - Transformer rectifiers - and Inverter designs
Gives arc voltage values to the control system of the feeder

27. What current and polarity is generally used with GMAW?
DCEP (Direct Current Electrode Positive) Reverse Polarity
To prevent leakage - Carbon Dioxide (CO2)
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

28. What is the purpose of a regulator and what does it indicate on its gauges?
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
Speed of the feed motor and - starting / stopping electrode feed
The Arc voltage
Reducing the gas source pressure to a constant working pressure

29. What is the purpose of the shielding gas used in GMAW?
(DCEP) Direct Current Electrode Positive or Reverse polarity
Pressure - The rate of flow of a shielding gas
Welding process that joins metals by heating them with an electric arc
Shielding the molten weld metal from atmospheric contamination

30. In the GMAW process what does amperage control?
Voltage is the force that overcomes resistance to allow amperage flow
Higher 26 to 35 arc volts
Penetration and burn - off rate of the electrode
Aluminum wire

31. What happens when the electrode extension is increased?
Power source - wire feeder - welding gun - Spooled filler wire - Shielding gas - and a ground
The resistace to electrical current flow increases with it. Causing the electrode to heat
...
The negative side of a welding unit

32. What term is used to describe when the workpiece is hooked to the negative pole on the power source?
Penetration and burn - off rate of the electrode
(DCEP) Direct Current Electrode Positive or Reverse polarity
Constant- speed wire feeders and Voltage- sennsing wire feeders
SMAW - GTAW

33. What is the main purpose of 'slope'?
Increasing inductance increases puddle fluidity - improves penatration - makes the bead flatter and smoother - and reduces spatter. To much inductance though will create erratic starts
DCEP (Direct Current Electrode Positive) Reverse Polarity
To limit the short circuiting current so that spatter is reduced
Dry ice can form within the flow control openings and cause blockage of shielding gas

34. 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
AWS and CSA

35. Is the arc voltage for spray transfer higher or lower than that used for short circuit transfer?
Motor driven generators - Transformer rectifiers - and Inverter designs
Wire feed speed
(DCEP) Direct Current Electrode Positive or Reverse polarity
Higher 26 to 35 arc volts

36. A 10 minute cycle of welding time vs cooling time a given machine can handle.
Cause flaking - which can clog the liner and contact tube
Duty cycle
Pressure vessels and the piping industry
If you dont know this check your phone

37. What power sources are used with the GMAW Process?
Constant current (CC)
Motor driven generators - Transformer rectifiers - and Inverter designs
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

38. What does voltage do in an electrical circuit?
The Arc voltage
Pressure - The rate of flow of a shielding gas
85%
Voltage is the force that overcomes resistance to allow amperage flow

39. What is another term for electrode holders for GMAW?
Constant voltage (CV)
15 feet (4.5 meters)
Guns
Generally not as accurate

40. What controls amperage when using GMAW?
Power source - wire feeder - welding gun - Spooled filler wire - Shielding gas - and a ground
Short- circuiting transfer - Globular transfer - Spray transfer
Wire feed speed
Molten metal is separated from the end of the filler wire by a squeezing force created by a magnetic field

41. Why is a fiber washer required and what cylinder gas requires it?
To prevent leakage - Carbon Dioxide (CO2)
The Arc voltage
V groove or U groove
Constant voltage (CV)

42. What does a flowmeter do and what does it measure?
The time rate of response for the current rise and fall
Pressure vessels and the piping industry
To prevent leakage - Carbon Dioxide (CO2)
Controls the rate of flow of a shielding gas to the gun nozzle

43. What output on the welding machine is used to rate the duty cycle?
Wire feed speed - Voltage control
Compressed gas cylinder - Liquid filled cylinder - or a Liquid bulk system
Minutes of elapsed time continually run (out of 10 minutes)
Spatter problems and poor weld appearance

44. What effect does increasing and decreasing the inductance have on the weld?
Increasing inductance increases puddle fluidity - improves penatration - makes the bead flatter and smoother - and reduces spatter. To much inductance though will create erratic starts
Higher 26 to 35 arc volts
Pressure - The rate of flow of a shielding gas
Constant current (CC)

45. List the three methods of metal transfer with GMAW
Short- circuiting transfer - Globular transfer - Spray transfer
By there current carrying capacity
Spatter problems and poor weld appearance
Constant current (CC)

46. In the GMAW process what does voltage control?
Cause flaking - which can clog the liner and contact tube
Duty cycle
Puddle fluidity
Electricaly operated valves that control the flow of shielding gas to the weld zone. The control switch located on the gun

47. What does the wire feeder control?
To prevent drawing of liquid CO2 (Carbon Dioxide)
Power source - wire feeder - welding gun - Spooled filler wire - Shielding gas - and a ground
If you dont know this check your phone
Speed of the feed motor and - starting / stopping electrode feed

48. What does the term GMAW identify?
Constant voltage (CV)
Cause flaking - which can clog the liner and contact tube
AWS and CSA
Gas metal arc welding

49. What type of power source is used with a constant speed wire feeder?
Constant voltage (CV)
If you dont know this check your phone
To limit the short circuiting current so that spatter is reduced
Reducing the gas source pressure to a constant working pressure

50. What are the 2 types of wire feeders available?
Compressed gas cylinder - Liquid filled cylinder - or a Liquid bulk system
Constant- speed wire feeders and Voltage- sennsing wire feeders
Voltage is the force that overcomes resistance to allow amperage flow
Guns