Test your basic knowledge |

Gas Metal Arc Welding

Instructions:

Answer 50 questions in 15 minutes.
If you are not ready to take this test, you can study here.
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?
Constant voltage (CV)
Voltage is the force that overcomes resistance to allow amperage flow
Minutes of elapsed time continually run (out of 10 minutes)
Pressure vessels and the piping industry

2. Why is the term GMAW preferred over MIG or MAG?
These terms are quite restrictive and often technically incorrect
Cause flaking - which can clog the liner and contact tube
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

3. Draw a typical volt/amp curve that would be found with a power source designed for SMAW or GTAW
Aluminum wire
If you dont know this check your phone
12 to 22 arc volts
Constant- speed wire feeders and Voltage- sennsing wire feeders

4. What happens when the electrode extension is increased?
The resistace to electrical current flow increases with it. Causing the electrode to heat
If you dont know this check your phone
5.8 to 12.5 L/min
Constant- speed wire feeders and Voltage- sennsing wire feeders

5. How are GMAW guns rated?
Insufficient current to melt the wire off cleanly
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
Penetration and burn - off rate of the electrode
By there current carrying capacity

6. What is the disadvantage of the gauge preset type of regulator/flowmeter?
Wire feed speed - Voltage control
Generally not as accurate
Higher 26 to 35 arc volts
V groove or U groove

7. Why is a fiber washer required and what cylinder gas requires it?
Pressure - The rate of flow of a shielding gas
Constant- speed wire feeders and Voltage- sennsing wire feeders
Welding Current - Filler wire diameter - arc length - type of shielding - position of the weld
To prevent leakage - Carbon Dioxide (CO2)

8. What controls amperage when using GMAW?
15 feet (4.5 meters)
3
SMAW - GTAW
Wire feed speed

9. A machine with a 70% duty cycle can run at its max for 7 minutes with a cooling cycle of only _ minutes.
Higher 26 to 35 arc volts
3
Welding process that joins metals by heating them with an electric arc
To prevent drawing of liquid CO2 (Carbon Dioxide)

10. List the basic equipment requirements for the GMAW process
Dry ice can form within the flow control openings and cause blockage of shielding gas
Insufficient current to melt the wire off cleanly
Power source - wire feeder - welding gun - Spooled filler wire - Shielding gas - and a ground
Molten metal is separated from the end of the filler wire by a squeezing force created by a magnetic field

11. What is an advantage of pulsed arc transfer with GMAW?
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
The resistace to electrical current flow increases with it. Causing the electrode to heat
Heat input is less than spray transfer - resulting in less distortion - Used in all positions due to controlling the weld metal freeze
When the filler wire is in direct contract with the base metal

12. What is the preferred drive roll design for solid wires?
Cause flaking - which can clog the liner and contact tube
V groove or U groove
National Electrical Manufactures Association
Pressure vessels and the piping industry

13. What is the key advantage of short circuiting transfer?
The time rate of response for the current rise and fall
National Electrical Manufactures Association
Voltage is the force that overcomes resistance to allow amperage flow
Minimum distortion due to low heat input

14. What is the minimum % value of argon that must be present to use the spray transfer method of GMAW?
Insufficient current to melt the wire off cleanly
85%
5.8 to 12.5 L/min
3

15. What processes are constant current (CC) power sources designed to be used with?
Electricaly operated valves that control the flow of shielding gas to the weld zone. The control switch located on the gun
SMAW - GTAW
Dry ice can form within the flow control openings and cause blockage of shielding gas
Molten metal is separated from the end of the filler wire by a squeezing force created by a magnetic field

16. What current and polarity is generally used with GMAW?
To limit the short circuiting current so that spatter is reduced
The resistace to electrical current flow increases with it. Causing the electrode to heat
DCEP (Direct Current Electrode Positive) Reverse Polarity
Voltage is the force that overcomes resistance to allow amperage flow

17. List the factors that determine the mode of metal transfer
Welding Current - Filler wire diameter - arc length - type of shielding - position of the weld
V groove or U groove
Penetration and burn - off rate of the electrode
The negative side of a welding unit

18. When using flat drive rolls with too much pressure on copper coated solid wires what problem could take place?
By there current carrying capacity
Electricaly operated valves that control the flow of shielding gas to the weld zone. The control switch located on the gun
Aluminum wire
Cause flaking - which can clog the liner and contact tube

19. Give a description of 'pinch effect'
5.8 to 12.5 L/min
(DCEP) Direct Current Electrode Positive or Reverse polarity
Molten metal is separated from the end of the filler wire by a squeezing force created by a magnetic field
Constant- speed wire feeders and Voltage- sennsing wire feeders

20. Give a brief description of the GMAW process
Welding process that joins metals by heating them with an electric arc
Welding Current - Filler wire diameter - arc length - type of shielding - position of the weld
Wire feeds smoothly (yet will slip should a problem occur in the gun)
When the filler wire is in direct contract with the base metal

21. What is the recommended electrode stick- out for .035 solid wire?
3
1/4 inch to 1/2 inch
V groove or U groove
...

22. Why is globular transfer generally avoided with GMAW?
Spatter problems and poor weld appearance
When the filler wire is in direct contract with the base metal
SMAW - GTAW
Generally not as accurate

23. When is the metal transferred with short circuit transfer?
Heat input is less than spray transfer - resulting in less distortion - Used in all positions due to controlling the weld metal freeze
When the filler wire is in direct contract with the base metal
12 to 22 arc volts
1/4 inch to 1/2 inch

24. Draw a typical volt amp curve for a machine that is designed for GMAW
To prevent drawing of liquid CO2 (Carbon Dioxide)
1/4 inch to 1/2 inch
If you dont know this check your phone
Duty cycle

25. What is the effect of too much slope?
Constant voltage (CV)
3
Insufficient current to melt the wire off cleanly
Controls the rate of flow of a shielding gas to the gun nozzle

26. What is the purpose of the shielding gas used in GMAW?
Minutes of elapsed time continually run (out of 10 minutes)
Shielding the molten weld metal from atmospheric contamination
When the filler wire is in direct contract with the base metal
Constant current (CC)

27. What 2 organizations designate specifications for GMAW wires?
Pressure - The rate of flow of a shielding gas
By there current carrying capacity
Spatter problems and poor weld appearance
AWS and CSA

28. What controls the wire speed on a voltage sensing wire feeder?
DCEP (Direct Current Electrode Positive) Reverse Polarity
The Arc voltage
Duty cycle
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 main purpose of 'slope'?
Short- circuiting transfer - Globular transfer - Spray transfer
To limit the short circuiting current so that spatter is reduced
...
Spatter problems and poor weld appearance

30. What effect does increasing and decreasing the inductance have on the weld?
Cause flaking - which can clog the liner and contact tube
When the filler wire is in direct contract with the base metal
Increasing inductance increases puddle fluidity - improves penatration - makes the bead flatter and smoother - and reduces spatter. To much inductance though will create erratic starts
Short- circuiting transfer - Globular transfer - Spray transfer

31. What would be an indication that the drive roll pressure is adjusted correctly?
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
These terms are quite restrictive and often technically incorrect
Wire feeds smoothly (yet will slip should a problem occur in the gun)

32. What type of power source is commonly used with a voltage sensing wire feeder?
Constant current (CC)
Insufficient current to melt the wire off cleanly
Wire feed speed
5.8 to 12.5 L/min

33. What does inductance control?
20 to 200 times per second
When the filler wire is in direct contract with the base metal
Minimum distortion due to low heat input
The time rate of response for the current rise and fall

34. Why is a line heater required when using GMAW?
Dry ice can form within the flow control openings and cause blockage of shielding gas
Constant- speed wire feeders and Voltage- sennsing wire feeders
Reducing the gas source pressure to a constant working pressure
20 to 200 times per second

35. What term is used to describe when the workpiece is hooked to the negative pole on the power source?
Pressure - The rate of flow of a shielding gas
Power source - wire feeder - welding gun - Spooled filler wire - Shielding gas - and a ground
(DCEP) Direct Current Electrode Positive or Reverse polarity
15 feet (4.5 meters)

36. What is a typical flow rate of CO2 for short circuit transfer?
Puddle fluidity
Gas metal arc welding
5.8 to 12.5 L/min
The resistace to electrical current flow increases with it. Causing the electrode to heat

37. Regulators control_____________ flowmeters SHOW____________.
If you dont know this check your phone
Motor driven generators - Transformer rectifiers - and Inverter designs
Pressure - The rate of flow of a shielding gas
The Arc voltage

38. What is the purpose of a regulator and what does it indicate on its gauges?
Reducing the gas source pressure to a constant working pressure
V groove or U groove
Aluminum wire
Cause flaking - which can clog the liner and contact tube

39. What is the required arc voltage used for short circuit transfer?
12 to 22 arc volts
Guns
Puddle fluidity
When the filler wire is in direct contract with the base metal

40. What is the maximum distance that hard wire can be successfully pushed?
Molten metal is separated from the end of the filler wire by a squeezing force created by a magnetic field
Welding Current - Filler wire diameter - arc length - type of shielding - position of the weld
15 feet (4.5 meters)
Electricaly operated valves that control the flow of shielding gas to the weld zone. The control switch located on the gun

41. What power sources are used with the GMAW Process?
Puddle fluidity
Spatter problems and poor weld appearance
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
Motor driven generators - Transformer rectifiers - and Inverter designs

42. List the three methods of metal transfer with GMAW
Penetration and burn - off rate of the electrode
Short- circuiting transfer - Globular transfer - Spray transfer
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

43. What does a flowmeter do and what does it measure?
Duty cycle
3
National Electrical Manufactures Association
Controls the rate of flow of a shielding gas to the gun nozzle

44. 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
Penetration and burn - off rate of the electrode
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

45. In the GMAW process what does voltage control?
Puddle fluidity
AWS and CSA
SMAW - GTAW
Reducing the gas source pressure to a constant working pressure

46. What is the reason glass 'tube' type flowmeters must have the tube mounted truly vertical?
National Electrical Manufactures Association
...
3
Pressure - The rate of flow of a shielding gas

47. What is the purpose of the pick- up lead on a voltage sensing wire feeder?
Welding Current - Filler wire diameter - arc length - type of shielding - position of the weld
Motor driven generators - Transformer rectifiers - and Inverter designs
DCEP (Direct Current Electrode Positive) Reverse Polarity
Gives arc voltage values to the control system of the feeder

48. 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
Increasing inductance increases puddle fluidity - improves penatration - makes the bead flatter and smoother - and reduces spatter. To much inductance though will create erratic starts
Insufficient current to melt the wire off cleanly

49. Why must CO2 cylinders be used in the vertical position?
To limit the short circuiting current so that spatter is reduced
Gas metal arc welding
5.8 to 12.5 L/min
To prevent drawing of liquid CO2 (Carbon Dioxide)

50. A pull type drive system is usually used on what type of material?
Wire feeds smoothly (yet will slip should a problem occur in the gun)
Higher 26 to 35 arc volts
National Electrical Manufactures Association
Aluminum wire