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 is the main purpose of 'slope'?
Guns
To limit the short circuiting current so that spatter is reduced
Insufficient current to melt the wire off cleanly
Penetration and burn - off rate of the electrode

2. What does the abbreviation NEMA stand for?
National Electrical Manufactures Association
Cause flaking - which can clog the liner and contact tube
3
Reducing the gas source pressure to a constant working pressure

3. Why is a fiber washer required and what cylinder gas requires it?
Puddle fluidity
To prevent leakage - Carbon Dioxide (CO2)
Pressure - The rate of flow of a shielding gas
15 feet (4.5 meters)

4. 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
Motor driven generators - Transformer rectifiers - and Inverter designs
Insufficient current to melt the wire off cleanly
Constant- speed wire feeders and Voltage- sennsing wire feeders

5. What 2 organizations designate specifications for GMAW wires?
12 to 22 arc volts
AWS and CSA
V groove or U groove
(DCEP) Direct Current Electrode Positive or Reverse polarity

6. What processes are constant current (CC) power sources designed to be used with?
If you dont know this check your phone
To prevent drawing of liquid CO2 (Carbon Dioxide)
Higher 26 to 35 arc volts
SMAW - GTAW

7. 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
Constant current (CC)
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

8. What is the disadvantage of the gauge preset type of regulator/flowmeter?
Generally not as accurate
3
To limit the short circuiting current so that spatter is reduced
Controls the rate of flow of a shielding gas to the gun nozzle

9. List the three methods of metal transfer with GMAW
Short- circuiting transfer - Globular transfer - Spray transfer
V groove or U groove
Gas metal arc welding
Controls the rate of flow of a shielding gas to the gun nozzle

10. What output on the welding machine is used to rate the duty cycle?
Controls the rate of flow of a shielding gas to the gun nozzle
15 feet (4.5 meters)
National Electrical Manufactures Association
Minutes of elapsed time continually run (out of 10 minutes)

11. A machine with a 70% duty cycle can run at its max for 7 minutes with a cooling cycle of only _ minutes.
Cause flaking - which can clog the liner and contact tube
85%
3
Gives arc voltage values to the control system of the feeder

12. What does the term GMAW identify?
Wire feed speed - Voltage control
Gas metal arc welding
Molten metal is separated from the end of the filler wire by a squeezing force created by a magnetic field
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

13. Draw a typical volt/amp curve that would be found with a power source designed for SMAW or GTAW
Controls the rate of flow of a shielding gas to the gun nozzle
If you dont know this check your phone
Cause flaking - which can clog the liner and contact tube
Wire feed speed - Voltage control

14. What is the effect of too much slope?
Insufficient current to melt the wire off cleanly
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
(DCEP) Direct Current Electrode Positive or Reverse polarity

15. With straight polarity where is 2/3 of the arc energy?
Constant- speed wire feeders and Voltage- sennsing wire feeders
The negative side of a welding unit
SMAW - GTAW
Speed of the feed motor and - starting / stopping electrode feed

16. What type of power source is used with a constant speed wire feeder?
Increasing inductance increases puddle fluidity - improves penatration - makes the bead flatter and smoother - and reduces spatter. To much inductance though will create erratic starts
If you dont know this check your phone
Constant voltage (CV)
If you dont know this check your phone

17. Why is a line heater required when using GMAW?
DCEP (Direct Current Electrode Positive) Reverse Polarity
Wire feed speed
To prevent drawing of liquid CO2 (Carbon Dioxide)
Dry ice can form within the flow control openings and cause blockage of shielding gas

18. A 10 minute cycle of welding time vs cooling time a given machine can handle.
Increasing inductance increases puddle fluidity - improves penatration - makes the bead flatter and smoother - and reduces spatter. To much inductance though will create erratic starts
Duty cycle
1/4 inch to 1/2 inch
Wire feed speed - Voltage control

19. What is the key advantage of short circuiting transfer?
Puddle fluidity
Minimum distortion due to low heat input
Constant- speed wire feeders and Voltage- sennsing wire feeders
Penetration and burn - off rate of the electrode

20. What is the purpose of the shielding gas used in GMAW?
Shielding the molten weld metal from atmospheric contamination
Gas metal arc welding
Generally not as accurate
When the filler wire is in direct contract with the base metal

21. List several industries that would use GMAW
The time rate of response for the current rise and fall
Motor driven generators - Transformer rectifiers - and Inverter designs
The negative side of a welding unit
Pressure vessels and the piping industry

22. 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
Speed of the feed motor and - starting / stopping electrode feed
Duty cycle
Motor driven generators - Transformer rectifiers - and Inverter designs

23. 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
Speed of the feed motor and - starting / stopping electrode feed
Wire feeds smoothly (yet will slip should a problem occur in the gun)
V groove or U groove

24. What does voltage do in an electrical circuit?
Voltage is the force that overcomes resistance to allow amperage flow
Duty cycle
When the filler wire is in direct contract with the base metal
Penetration and burn - off rate of the electrode

25. Why is globular transfer generally avoided with GMAW?
Speed of the feed motor and - starting / stopping electrode feed
Electricaly operated valves that control the flow of shielding gas to the weld zone. The control switch located on the gun
Spatter problems and poor weld appearance
Motor driven generators - Transformer rectifiers - and Inverter designs

26. What is the maximum distance that hard wire can be successfully pushed?
Shielding the molten weld metal from atmospheric contamination
15 feet (4.5 meters)
Gives arc voltage values to the control system of the feeder
(DCEP) Direct Current Electrode Positive or Reverse polarity

27. Regulators control_____________ flowmeters SHOW____________.
Heat input is less than spray transfer - resulting in less distortion - Used in all positions due to controlling the weld metal freeze
The negative side of a welding unit
3
Pressure - The rate of flow of a shielding gas

28. How are GMAW guns rated?
Insufficient current to melt the wire off cleanly
Pressure vessels and the piping industry
By there current carrying capacity
The Arc voltage

29. Why is the term GMAW preferred over MIG or MAG?
Insufficient current to melt the wire off cleanly
These terms are quite restrictive and often technically incorrect
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)

30. List 3 wire drive systems and give a short description of each
Pressure - The rate of flow of a shielding gas
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
Shielding the molten weld metal from atmospheric contamination
20 to 200 times per second

31. What is another term for electrode holders for GMAW?
Reducing the gas source pressure to a constant working pressure
Guns
12 to 22 arc volts
Power source - wire feeder - welding gun - Spooled filler wire - Shielding gas - and a ground

32. In the GMAW process what does amperage control?
1/4 inch to 1/2 inch
Minimum distortion due to low heat input
Penetration and burn - off rate of the electrode
The resistace to electrical current flow increases with it. Causing the electrode to heat

33. What type of power source is commonly used with a voltage sensing wire feeder?
Pressure vessels and the piping industry
Constant current (CC)
Reducing the gas source pressure to a constant working pressure
SMAW - GTAW

34. Why must CO2 cylinders be used in the vertical position?
By there current carrying capacity
To prevent drawing of liquid CO2 (Carbon Dioxide)
National Electrical Manufactures Association
SMAW - GTAW

35. A pull type drive system is usually used on what type of material?
Welding Current - Filler wire diameter - arc length - type of shielding - position of the weld
Aluminum wire
Short- circuiting transfer - Globular transfer - Spray transfer
Molten metal is separated from the end of the filler wire by a squeezing force created by a magnetic field

36. Give a brief description of the GMAW process
The time rate of response for the current rise and fall
If you dont know this check your phone
Welding Current - Filler wire diameter - arc length - type of shielding - position of the weld
Welding process that joins metals by heating them with an electric arc

37. What wire are knurled drive rolls most commonly used on?
Flux cored wires
By there current carrying capacity
To prevent drawing of liquid CO2 (Carbon Dioxide)
Spatter problems and poor weld appearance

38. What controls amperage when using GMAW?
Constant voltage (CV)
Dry ice can form within the flow control openings and cause blockage of shielding gas
Wire feed speed
Controls the rate of flow of a shielding gas to the gun nozzle

39. List 3 forms compressed gases may be supplied for welding
Compressed gas cylinder - Liquid filled cylinder - or a Liquid bulk system
Wire feeds smoothly (yet will slip should a problem occur in the gun)
Generally not as accurate
...

40. What are the 2 types of wire feeders available?
To prevent drawing of liquid CO2 (Carbon Dioxide)
Constant- speed wire feeders and Voltage- sennsing wire feeders
3
20 to 200 times per second

41. What is an advantage of pulsed arc transfer with GMAW?
The negative side of a welding unit
AWS and CSA
Heat input is less than spray transfer - resulting in less distortion - Used in all positions due to controlling the weld metal freeze
1/4 inch to 1/2 inch

42. What controls the wire speed on a voltage sensing wire feeder?
The Arc voltage
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
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)

43. How many times per second does short circuiting take place?
Wire feed speed
Welding process that joins metals by heating them with an electric arc
20 to 200 times per second
5.8 to 12.5 L/min

44. Draw a typical volt amp curve for a machine that is designed for GMAW
If you dont know this check your phone
20 to 200 times per second
Welding process that joins metals by heating them with an electric arc
5.8 to 12.5 L/min

45. List the factors that determine the mode of metal transfer
Welding Current - Filler wire diameter - arc length - type of shielding - position of the weld
15 feet (4.5 meters)
AWS and CSA
12 to 22 arc volts

46. What power sources are used with the GMAW Process?
Reducing the gas source pressure to a constant working pressure
Motor driven generators - Transformer rectifiers - and Inverter designs
Welding process that joins metals by heating them with an electric arc
Duty cycle

47. Is the arc voltage for spray transfer higher or lower than that used for short circuit transfer?
Higher 26 to 35 arc volts
The negative side of a welding unit
Welding Current - Filler wire diameter - arc length - type of shielding - position of the weld
85%

48. What is the preferred drive roll design for solid wires?
V groove or U groove
Constant current (CC)
DCEP (Direct Current Electrode Positive) Reverse Polarity
20 to 200 times per second

49. What does the wire feeder control?
12 to 22 arc volts
Speed of the feed motor and - starting / stopping electrode feed
If you dont know this check your phone
The negative side of a welding unit

50. What 2 controls are found on a GMAW set- up?
Short- circuiting transfer - Globular transfer - Spray transfer
Constant- speed wire feeders and Voltage- sennsing wire feeders
Dry ice can form within the flow control openings and cause blockage of shielding gas
Wire feed speed - Voltage control