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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 term is used to describe when the workpiece is hooked to the negative pole on the power source?
Aluminum wire
(DCEP) Direct Current Electrode Positive or Reverse polarity
To limit the short circuiting current so that spatter is reduced
Duty cycle

2. What type of power source is commonly used with a voltage sensing wire feeder?
1/4 inch to 1/2 inch
Constant current (CC)
Insufficient current to melt the wire off cleanly
Welding process that joins metals by heating them with an electric arc

3. What is an advantage of pulsed arc transfer with GMAW?
AWS and CSA
Compressed gas cylinder - Liquid filled cylinder - or a Liquid bulk system
Constant- speed wire feeders and Voltage- sennsing wire feeders
Heat input is less than spray transfer - resulting in less distortion - Used in all positions due to controlling the weld metal freeze

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

5. What does the term GMAW identify?
Gas metal arc welding
Gives arc voltage values to the control system of the feeder
Pressure - The rate of flow of a shielding gas
AWS and CSA

6. What is the main purpose of 'slope'?
To limit the short circuiting current so that spatter is reduced
Wire feed speed - Voltage control
Welding Current - Filler wire diameter - arc length - type of shielding - position of the weld
Pressure vessels and the piping industry

7. Draw a typical volt/amp curve that would be found with a power source designed for SMAW or GTAW
Constant current (CC)
Insufficient current to melt the wire off cleanly
If you dont know this check your phone
Reducing the gas source pressure to a constant working pressure

8. What is a typical flow rate of CO2 for short circuit transfer?
5.8 to 12.5 L/min
Voltage is the force that overcomes resistance to allow amperage flow
Welding process that joins metals by heating them with an electric arc
...

9. What is the required arc voltage used for short circuit transfer?
...
To prevent leakage - Carbon Dioxide (CO2)
12 to 22 arc volts
When the filler wire is in direct contract with the base metal

10. 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
5.8 to 12.5 L/min
1/4 inch to 1/2 inch

11. Why is globular transfer generally avoided with GMAW?
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
When the filler wire is in direct contract with the base metal
Spatter problems and poor weld appearance

12. List 3 wire drive systems and give a short description of each
Voltage is the force that overcomes resistance to allow amperage flow
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
These terms are quite restrictive and often technically incorrect
Heat input is less than spray transfer - resulting in less distortion - Used in all positions due to controlling the weld metal freeze

13. What is the recommended electrode stick- out for .035 solid wire?
These terms are quite restrictive and often technically incorrect
Higher 26 to 35 arc volts
1/4 inch to 1/2 inch
Welding process that joins metals by heating them with an electric arc

14. When using flat drive rolls with too much pressure on copper coated solid wires what problem could take place?
Cause flaking - which can clog the liner and contact tube
Welding process that joins metals by heating them with an electric arc
Insufficient current to melt the wire off cleanly
85%

15. What wire are knurled drive rolls most commonly used on?
Flux cored wires
3
Pressure - The rate of flow of a shielding gas
The Arc voltage

16. What does the wire feeder control?
Speed of the feed motor and - starting / stopping electrode feed
AWS and CSA
If you dont know this check your phone
When the filler wire is in direct contract with the base metal

17. What is the preferred drive roll design for solid wires?
Voltage is the force that overcomes resistance to allow amperage flow
V groove or U groove
SMAW - GTAW
Gas metal arc welding

18. What effect does increasing and decreasing the inductance have on the weld?
12 to 22 arc volts
Pressure - The rate of flow of a shielding gas
Increasing inductance increases puddle fluidity - improves penatration - makes the bead flatter and smoother - and reduces spatter. To much inductance though will create erratic starts
5.8 to 12.5 L/min

19. What controls amperage when using GMAW?
The negative side of a welding unit
Wire feed speed
Dry ice can form within the flow control openings and cause blockage of shielding gas
Pressure - The rate of flow of a shielding gas

20. What 2 controls are found on a GMAW set- up?
5.8 to 12.5 L/min
SMAW - GTAW
Aluminum wire
Wire feed speed - Voltage control

21. What type of power source is used with a constant speed wire feeder?
Higher 26 to 35 arc volts
85%
Shielding the molten weld metal from atmospheric contamination
Constant voltage (CV)

22. What is the minimum % value of argon that must be present to use the spray transfer method of GMAW?
Higher 26 to 35 arc volts
Controls the rate of flow of a shielding gas to the gun nozzle
85%
Dry ice can form within the flow control openings and cause blockage of shielding gas

23. What output on the welding machine is used to rate the duty cycle?
Constant voltage (CV)
Minimum distortion due to low heat input
Minutes of elapsed time continually run (out of 10 minutes)
Higher 26 to 35 arc volts

24. How many times per second does short circuiting take place?
Puddle fluidity
Cause flaking - which can clog the liner and contact tube
5.8 to 12.5 L/min
20 to 200 times per second

25. Draw a typical volt amp curve for a machine that is designed for GMAW
The negative side of a welding unit
Flux cored wires
3
If you dont know this check your phone

26. How are GMAW guns rated?
Dry ice can form within the flow control openings and cause blockage of shielding gas
By there current carrying capacity
Cause flaking - which can clog the liner and contact tube
Duty cycle

27. What does the abbreviation NEMA stand for?
Constant- speed wire feeders and Voltage- sennsing wire feeders
National Electrical Manufactures Association
To prevent leakage - Carbon Dioxide (CO2)
By there current carrying capacity

28. Give a brief description of the GMAW process
Increasing inductance increases puddle fluidity - improves penatration - makes the bead flatter and smoother - and reduces spatter. To much inductance though will create erratic starts
Pressure - The rate of flow of a shielding gas
Welding process that joins metals by heating them with an electric arc
The resistace to electrical current flow increases with it. Causing the electrode to heat

29. A machine with a 70% duty cycle can run at its max for 7 minutes with a cooling cycle of only _ minutes.
3
Minimum distortion due to low heat input
Controls the rate of flow of a shielding gas to the gun nozzle
If you dont know this check your phone

30. Why must CO2 cylinders be used in the vertical position?
Heat input is less than spray transfer - resulting in less distortion - Used in all positions due to controlling the weld metal freeze
To prevent drawing of liquid CO2 (Carbon Dioxide)
DCEP (Direct Current Electrode Positive) Reverse Polarity
Generally not as accurate

31. What does a flowmeter do and what does it measure?
To limit the short circuiting current so that spatter is reduced
If you dont know this check your phone
Controls the rate of flow of a shielding gas to the gun nozzle
National Electrical Manufactures Association

32. What are the 2 types of wire feeders available?
Constant- speed wire feeders and Voltage- sennsing wire feeders
Speed of the feed motor and - starting / stopping electrode feed
These terms are quite restrictive and often technically incorrect
SMAW - GTAW

33. What processes are constant current (CC) power sources designed to be used with?
To prevent leakage - Carbon Dioxide (CO2)
SMAW - GTAW
Molten metal is separated from the end of the filler wire by a squeezing force created by a magnetic field
Higher 26 to 35 arc volts

34. What power sources are used with the GMAW Process?
Welding Current - Filler wire diameter - arc length - type of shielding - position of the weld
National Electrical Manufactures Association
Motor driven generators - Transformer rectifiers - and Inverter designs
...

35. What does voltage do in an electrical circuit?
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
Voltage is the force that overcomes resistance to allow amperage flow
1/4 inch to 1/2 inch
Penetration and burn - off rate of the electrode

36. What 2 organizations designate specifications for GMAW wires?
AWS and CSA
Welding Current - Filler wire diameter - arc length - type of shielding - position of the weld
National Electrical Manufactures Association
Higher 26 to 35 arc volts

37. Why is a fiber washer required and what cylinder gas requires it?
To prevent drawing of liquid CO2 (Carbon Dioxide)
To prevent leakage - Carbon Dioxide (CO2)
Wire feed speed - Voltage control
...

38. A 10 minute cycle of welding time vs cooling time a given machine can handle.
15 feet (4.5 meters)
Constant- speed wire feeders and Voltage- sennsing wire feeders
Duty cycle
Guns

39. What is a solenoid valve and what actuates it?
Constant current (CC)
Electricaly operated valves that control the flow of shielding gas to the weld zone. The control switch located on the gun
Generally not as accurate
Cause flaking - which can clog the liner and contact tube

40. What is the reason glass 'tube' type flowmeters must have the tube mounted truly vertical?
Higher 26 to 35 arc volts
5.8 to 12.5 L/min
...
Generally not as accurate

41. What is the purpose of the pick- up lead on a voltage sensing wire feeder?
DCEP (Direct Current Electrode Positive) Reverse Polarity
Gives arc voltage values to the control system of the feeder
Flux cored wires
Pressure vessels and the piping industry

42. List several industries that would use GMAW
Dry ice can form within the flow control openings and cause blockage of shielding gas
Voltage is the force that overcomes resistance to allow amperage flow
Pressure vessels and the piping industry
Motor driven generators - Transformer rectifiers - and Inverter designs

43. With straight polarity where is 2/3 of the arc energy?
Minimum distortion due to low heat input
The negative side of a welding unit
Minutes of elapsed time continually run (out of 10 minutes)
Welding Current - Filler wire diameter - arc length - type of shielding - position of the weld

44. What controls the wire speed on a voltage sensing wire feeder?
5.8 to 12.5 L/min
Gas metal arc welding
The Arc voltage
The negative side of a welding unit

45. When is the metal transferred with short circuit transfer?
When the filler wire is in direct contract with the base metal
Welding process that joins metals by heating them with an electric arc
National Electrical Manufactures Association
The negative side of a welding unit

46. In the GMAW process what does amperage control?
Penetration and burn - off rate of the electrode
15 feet (4.5 meters)
Power source - wire feeder - welding gun - Spooled filler wire - Shielding gas - and a ground
5.8 to 12.5 L/min

47. What happens when the electrode extension is increased?
SMAW - GTAW
Electricaly operated valves that control the flow of shielding gas to the weld zone. The control switch located on the gun
Puddle fluidity
The resistace to electrical current flow increases with it. Causing the electrode to heat

48. Why is a line heater required when using GMAW?
Dry ice can form within the flow control openings and cause blockage of shielding gas
Cause flaking - which can clog the liner and contact tube
Duty cycle
Compressed gas cylinder - Liquid filled cylinder - or a Liquid bulk system

49. In the GMAW process what does voltage control?
Puddle fluidity
To prevent leakage - Carbon Dioxide (CO2)
These terms are quite restrictive and often technically incorrect
Aluminum wire

50. Regulators control_____________ flowmeters SHOW____________.
When the filler wire is in direct contract with the base metal
Controls the rate of flow of a shielding gas to the gun nozzle
Pressure - The rate of flow of a shielding gas
Cause flaking - which can clog the liner and contact tube