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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 type of power source is used with a constant speed wire feeder?
If you dont know this check your phone
Minutes of elapsed time continually run (out of 10 minutes)
Constant voltage (CV)
15 feet (4.5 meters)

2. What effect does increasing and decreasing the inductance have on the weld?
SMAW - GTAW
Pressure vessels and the piping industry
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

3. What is the purpose of the shielding gas used in GMAW?
Shielding the molten weld metal from atmospheric contamination
To limit the short circuiting current so that spatter is reduced
When the filler wire is in direct contract with the base metal
Insufficient current to melt the wire off cleanly

4. What is the recommended electrode stick- out for .035 solid wire?
...
Puddle fluidity
1/4 inch to 1/2 inch
V groove or U groove

5. What 2 organizations designate specifications for GMAW wires?
1/4 inch to 1/2 inch
Shielding the molten weld metal from atmospheric contamination
AWS and CSA
15 feet (4.5 meters)

6. What happens when the electrode extension is increased?
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
Higher 26 to 35 arc volts
To prevent leakage - Carbon Dioxide (CO2)

7. List the basic equipment requirements for the GMAW process
Power source - wire feeder - welding gun - Spooled filler wire - Shielding gas - and a ground
To prevent leakage - Carbon Dioxide (CO2)
DCEP (Direct Current Electrode Positive) Reverse Polarity
Welding Current - Filler wire diameter - arc length - type of shielding - position of the weld

8. What does the abbreviation NEMA stand for?
Voltage is the force that overcomes resistance to allow amperage flow
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
National Electrical Manufactures Association

9. What is the main purpose of 'slope'?
National Electrical Manufactures Association
DCEP (Direct Current Electrode Positive) Reverse Polarity
Guns
To limit the short circuiting current so that spatter is reduced

10. What is an advantage of pulsed arc transfer with GMAW?
Welding process that joins metals by heating them with an electric arc
To prevent leakage - Carbon Dioxide (CO2)
Gives arc voltage values to the control system of the feeder
Heat input is less than spray transfer - resulting in less distortion - Used in all positions due to controlling the weld metal freeze

11. Why is a fiber washer required and what cylinder gas requires it?
V groove or U groove
5.8 to 12.5 L/min
15 feet (4.5 meters)
To prevent leakage - Carbon Dioxide (CO2)

12. A 10 minute cycle of welding time vs cooling time a given machine can handle.
Duty cycle
These terms are quite restrictive and often technically incorrect
Wire feeds smoothly (yet will slip should a problem occur in the gun)
Heat input is less than spray transfer - resulting in less distortion - Used in all positions due to controlling the weld metal freeze

13. When is the metal transferred with short circuit transfer?
Reducing the gas source pressure to a constant working pressure
Aluminum wire
When the filler wire is in direct contract with the base metal
Constant voltage (CV)

14. List 3 forms compressed gases may be supplied for welding
Flux cored wires
Compressed gas cylinder - Liquid filled cylinder - or a Liquid bulk system
Short- circuiting transfer - Globular transfer - Spray transfer
Pressure - The rate of flow of a shielding gas

15. Is the arc voltage for spray transfer higher or lower than that used for short circuit transfer?
SMAW - GTAW
15 feet (4.5 meters)
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

16. What is the required arc voltage used for short circuit transfer?
To prevent leakage - Carbon Dioxide (CO2)
Speed of the feed motor and - starting / stopping electrode feed
12 to 22 arc volts
The Arc voltage

17. List 3 wire drive systems and give a short description of each
Wire feeds smoothly (yet will slip should a problem occur in the gun)
Compressed gas cylinder - Liquid filled cylinder - or a Liquid bulk system
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
V groove or U groove

18. List several industries that would use GMAW
Duty cycle
To prevent leakage - Carbon Dioxide (CO2)
Welding Current - Filler wire diameter - arc length - type of shielding - position of the weld
Pressure vessels and the piping industry

19. What type of power source is commonly used with a voltage sensing wire feeder?
Power source - wire feeder - welding gun - Spooled filler wire - Shielding gas - and a ground
To prevent drawing of liquid CO2 (Carbon Dioxide)
Gas metal arc welding
Constant current (CC)

20. How many times per second does short circuiting take place?
Power source - wire feeder - welding gun - Spooled filler wire - Shielding gas - and a ground
20 to 200 times per second
Flux cored wires
Increasing inductance increases puddle fluidity - improves penatration - makes the bead flatter and smoother - and reduces spatter. To much inductance though will create erratic starts

21. What is another term for electrode holders for GMAW?
Reducing the gas source pressure to a constant working pressure
Guns
By there current carrying capacity
The Arc voltage

22. What is a typical flow rate of CO2 for short circuit transfer?
Short- circuiting transfer - Globular transfer - Spray transfer
(DCEP) Direct Current Electrode Positive or Reverse polarity
5.8 to 12.5 L/min
3

23. What controls the wire speed on a voltage sensing wire feeder?
The Arc voltage
3
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

24. A pull type drive system is usually used on what type of material?
If you dont know this check your phone
...
Aluminum wire
Minutes of elapsed time continually run (out of 10 minutes)

25. What term is used to describe when the workpiece is hooked to the negative pole on the power source?
National Electrical Manufactures Association
DCEP (Direct Current Electrode Positive) Reverse Polarity
(DCEP) Direct Current Electrode Positive or Reverse polarity
1/4 inch to 1/2 inch

26. What controls amperage when using GMAW?
85%
Wire feed speed
SMAW - GTAW
Power source - wire feeder - welding gun - Spooled filler wire - Shielding gas - and a ground

27. What is the disadvantage of the gauge preset type of regulator/flowmeter?
Generally not as accurate
Spatter problems and poor weld appearance
(DCEP) Direct Current Electrode Positive or Reverse polarity
To prevent leakage - Carbon Dioxide (CO2)

28. What does the term GMAW identify?
Constant current (CC)
Electricaly operated valves that control the flow of shielding gas to the weld zone. The control switch located on the gun
Gas metal arc welding
National Electrical Manufactures Association

29. What is a solenoid valve and what actuates it?
Electricaly operated valves that control the flow of shielding gas to the weld zone. The control switch located on the gun
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
Puddle fluidity

30. How are GMAW guns rated?
Wire feed speed
Gas metal arc welding
Guns
By there current carrying capacity

31. What is the effect of too much slope?
Shielding the molten weld metal from atmospheric contamination
Insufficient current to melt the wire off cleanly
Welding process that joins metals by heating them with an electric arc
These terms are quite restrictive and often technically incorrect

32. A machine with a 70% duty cycle can run at its max for 7 minutes with a cooling cycle of only _ minutes.
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 voltage (CV)
SMAW - GTAW
3

33. What is the purpose of the pick- up lead on a voltage sensing wire feeder?
These terms are quite restrictive and often technically incorrect
Reducing the gas source pressure to a constant working pressure
Dry ice can form within the flow control openings and cause blockage of shielding gas
Gives arc voltage values to the control system of the feeder

34. Draw a typical volt amp curve for a machine that is designed for GMAW
Constant- speed wire feeders and Voltage- sennsing wire feeders
If you dont know this check your phone
Wire feed speed - Voltage control
(DCEP) Direct Current Electrode Positive or Reverse polarity

35. What wire are knurled drive rolls most commonly used on?
Flux cored wires
85%
Shielding the molten weld metal from atmospheric contamination
Constant- speed wire feeders and Voltage- sennsing wire feeders

36. What are the 2 types of wire feeders available?
Constant current (CC)
Minimum distortion due to low heat input
Constant- speed wire feeders and Voltage- sennsing wire feeders
Speed of the feed motor and - starting / stopping electrode feed

37. What is the minimum % value of argon that must be present to use the spray transfer method of GMAW?
85%
National Electrical Manufactures Association
Shielding the molten weld metal from atmospheric contamination
Welding process that joins metals by heating them with an electric arc

38. When using flat drive rolls with too much pressure on copper coated solid wires what problem could take place?
Insufficient current to melt the wire off cleanly
Power source - wire feeder - welding gun - Spooled filler wire - Shielding gas - and a ground
Aluminum wire
Cause flaking - which can clog the liner and contact tube

39. 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
The Arc voltage
Constant- speed wire feeders and Voltage- sennsing wire feeders
To limit the short circuiting current so that spatter is reduced

40. What is the purpose of a regulator and what does it indicate on its gauges?
Motor driven generators - Transformer rectifiers - and Inverter designs
Wire feeds smoothly (yet will slip should a problem occur in the gun)
Short- circuiting transfer - Globular transfer - Spray transfer
Reducing the gas source pressure to a constant working pressure

41. What does inductance control?
Insufficient current to melt the wire off cleanly
To prevent drawing of liquid CO2 (Carbon Dioxide)
3
The time rate of response for the current rise and fall

42. What processes are constant current (CC) power sources designed to be used with?
Gas metal arc welding
To prevent leakage - Carbon Dioxide (CO2)
Guns
SMAW - GTAW

43. What current and polarity is generally used with GMAW?
Generally not as accurate
DCEP (Direct Current Electrode Positive) Reverse Polarity
12 to 22 arc volts
The time rate of response for the current rise and fall

44. In the GMAW process what does voltage control?
Speed of the feed motor and - starting / stopping electrode feed
To prevent leakage - Carbon Dioxide (CO2)
Puddle fluidity
Constant voltage (CV)

45. What does the wire feeder control?
Speed of the feed motor and - starting / stopping electrode feed
By there current carrying capacity
Guns
Pressure vessels and the piping industry

46. What is the key advantage of short circuiting transfer?
Minimum distortion due to low heat input
Dry ice can form within the flow control openings and cause blockage of shielding gas
SMAW - GTAW
Wire feed speed

47. List the three methods of metal transfer with GMAW
Constant- speed wire feeders and Voltage- sennsing wire feeders
Short- circuiting transfer - Globular transfer - Spray transfer
Voltage is the force that overcomes resistance to allow amperage flow
Pressure - The rate of flow of a shielding gas

48. Why must CO2 cylinders be used in the vertical position?
The negative side of a welding unit
The resistace to electrical current flow increases with it. Causing the electrode to heat
When the filler wire is in direct contract with the base metal
To prevent drawing of liquid CO2 (Carbon Dioxide)

49. What is the reason glass 'tube' type flowmeters must have the tube mounted truly vertical?
...
If you dont know this check your phone
AWS and CSA
Constant voltage (CV)

50. With straight polarity where is 2/3 of the arc energy?
3
Shielding the molten weld metal from atmospheric contamination
To limit the short circuiting current so that spatter is reduced
The negative side of a welding unit