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. Draw a typical volt/amp curve that would be found with a power source designed for SMAW or GTAW
DCEP (Direct Current Electrode Positive) Reverse Polarity
If you dont know this check your phone
National Electrical Manufactures Association
When the filler wire is in direct contract with the base metal

2. What is an advantage of pulsed arc transfer with GMAW?
Insufficient current to melt the wire off cleanly
Speed of the feed motor and - starting / stopping electrode feed
Generally not as accurate
Heat input is less than spray transfer - resulting in less distortion - Used in all positions due to controlling the weld metal freeze

3. Regulators control_____________ flowmeters SHOW____________.
Minutes of elapsed time continually run (out of 10 minutes)
Voltage is the force that overcomes resistance to allow amperage flow
Wire feed speed - Voltage control
Pressure - The rate of flow of a shielding gas

4. A 10 minute cycle of welding time vs cooling time a given machine can handle.
Pressure vessels and the piping industry
Cause flaking - which can clog the liner and contact tube
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

5. What is the required arc voltage used for short circuit transfer?
By there current carrying capacity
Pressure - The rate of flow of a shielding gas
Controls the rate of flow of a shielding gas to the gun nozzle
12 to 22 arc volts

6. What is the minimum % value of argon that must be present to use the spray transfer method of GMAW?
Duty cycle
85%
To limit the short circuiting current so that spatter is reduced
Aluminum wire

7. 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
Minutes of elapsed time continually run (out of 10 minutes)
85%

8. List 3 wire drive systems and give a short description of each
Constant voltage (CV)
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
Generally not as accurate
12 to 22 arc volts

9. When using flat drive rolls with too much pressure on copper coated solid wires what problem could take place?
5.8 to 12.5 L/min
Penetration and burn - off rate of the electrode
Cause flaking - which can clog the liner and contact tube
Wire feed speed

10. How many times per second does short circuiting take place?
Duty cycle
Motor driven generators - Transformer rectifiers - and Inverter designs
To prevent drawing of liquid CO2 (Carbon Dioxide)
20 to 200 times per second

11. What controls amperage when using GMAW?
Generally not as accurate
Wire feed speed
3
Minimum distortion due to low heat input

12. What term is used to describe when the workpiece is hooked to the negative pole on the power source?
(DCEP) Direct Current Electrode Positive or Reverse polarity
Penetration and burn - off rate of the electrode
Speed of the feed motor and - starting / stopping electrode feed
Short- circuiting transfer - Globular transfer - Spray transfer

13. What controls the wire speed on a voltage sensing wire feeder?
Wire feeds smoothly (yet will slip should a problem occur in the gun)
The Arc voltage
By there current carrying capacity
If you dont know this check your phone

14. 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
If you dont know this check your phone
Pressure - The rate of flow of a shielding gas
Guns

15. What wire are knurled drive rolls most commonly used on?
Wire feed speed
Pressure vessels and the piping industry
Flux cored wires
Dry ice can form within the flow control openings and cause blockage of shielding gas

16. With straight polarity where is 2/3 of the arc energy?
Reducing the gas source pressure to a constant working pressure
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
The negative side of a welding unit

17. Why is a fiber washer required and what cylinder gas requires it?
Wire feed speed
Cause flaking - which can clog the liner and contact tube
To prevent leakage - Carbon Dioxide (CO2)
If you dont know this check your phone

18. What output on the welding machine is used to rate the duty cycle?
Insufficient current to melt the wire off cleanly
12 to 22 arc volts
To prevent drawing of liquid CO2 (Carbon Dioxide)
Minutes of elapsed time continually run (out of 10 minutes)

19. List 3 forms compressed gases may be supplied for welding
Pressure vessels and the piping industry
Welding process that joins metals by heating them with an electric arc
The negative side of a welding unit
Compressed gas cylinder - Liquid filled cylinder - or a Liquid bulk system

20. What is another term for electrode holders for GMAW?
Guns
3
Wire feed speed
Power source - wire feeder - welding gun - Spooled filler wire - Shielding gas - and a ground

21. A machine with a 70% duty cycle can run at its max for 7 minutes with a cooling cycle of only _ minutes.
Motor driven generators - Transformer rectifiers - and Inverter designs
Gives arc voltage values to the control system of the feeder
3
Dry ice can form within the flow control openings and cause blockage of shielding gas

22. What 2 controls are found on a GMAW set- up?
To prevent drawing of liquid CO2 (Carbon Dioxide)
Cause flaking - which can clog the liner and contact tube
Minimum distortion due to low heat input
Wire feed speed - Voltage control

23. List the factors that determine the mode of metal transfer
The negative side of a welding unit
Motor driven generators - Transformer rectifiers - and Inverter designs
Welding Current - Filler wire diameter - arc length - type of shielding - position of the weld
Aluminum wire

24. Why is a line heater required when using GMAW?
If you dont know this check your phone
Dry ice can form within the flow control openings and cause blockage of shielding gas
Wire feeds smoothly (yet will slip should a problem occur in the gun)
Flux cored wires

25. What 2 organizations designate specifications for GMAW wires?
AWS and CSA
Minimum distortion due to low heat input
1/4 inch to 1/2 inch
These terms are quite restrictive and often technically incorrect

26. What power sources are used with the GMAW Process?
1/4 inch to 1/2 inch
Spatter problems and poor weld appearance
Aluminum wire
Motor driven generators - Transformer rectifiers - and Inverter designs

27. What processes are constant current (CC) power sources designed to be used with?
Minutes of elapsed time continually run (out of 10 minutes)
SMAW - GTAW
Pressure - The rate of flow of a shielding gas
Penetration and burn - off rate of the electrode

28. List several industries that would use GMAW
5.8 to 12.5 L/min
Pressure vessels and the piping industry
Guns
...

29. What current and polarity is generally used with GMAW?
DCEP (Direct Current Electrode Positive) Reverse Polarity
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
The Arc voltage

30. What would be an indication that the drive roll pressure is adjusted correctly?
These terms are quite restrictive and often technically incorrect
To limit the short circuiting current so that spatter is reduced
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

31. What type of power source is commonly used with a voltage sensing wire feeder?
(DCEP) Direct Current Electrode Positive or Reverse polarity
Constant current (CC)
Puddle fluidity
When the filler wire is in direct contract with the base metal

32. A pull type drive system is usually used on what type of material?
1/4 inch to 1/2 inch
Pressure vessels and the piping industry
Dry ice can form within the flow control openings and cause blockage of shielding gas
Aluminum wire

33. What is the preferred drive roll design for solid wires?
Voltage is the force that overcomes resistance to allow amperage flow
15 feet (4.5 meters)
Gas metal arc welding
V groove or U groove

34. What is a typical flow rate of CO2 for short circuit transfer?
Pressure - The rate of flow of a shielding gas
5.8 to 12.5 L/min
Electricaly operated valves that control the flow of shielding gas to the weld zone. The control switch located on the gun
National Electrical Manufactures Association

35. In the GMAW process what does voltage control?
Spatter problems and poor weld appearance
Dry ice can form within the flow control openings and cause blockage of shielding gas
Puddle fluidity
Motor driven generators - Transformer rectifiers - and Inverter designs

36. What happens when the electrode extension is increased?
The resistace to electrical current flow increases with it. Causing the electrode to heat
Higher 26 to 35 arc volts
Spatter problems and poor weld appearance
Pressure vessels and the piping industry

37. How are GMAW guns rated?
Wire feed speed
By there current carrying capacity
Cause flaking - which can clog the liner and contact tube
If you dont know this check your phone

38. In the GMAW process what does amperage control?
Aluminum wire
Penetration and burn - off rate of the electrode
Welding Current - Filler wire diameter - arc length - type of shielding - position of the weld
Spatter problems and poor weld appearance

39. What is the effect of too much slope?
85%
The Arc voltage
Gas metal arc welding
Insufficient current to melt the wire off cleanly

40. Give a brief description of the GMAW process
To prevent leakage - Carbon Dioxide (CO2)
1/4 inch to 1/2 inch
Power source - wire feeder - welding gun - Spooled filler wire - Shielding gas - and a ground
Welding process that joins metals by heating them with an electric arc

41. What type of power source is used with a constant speed wire feeder?
Constant voltage (CV)
Constant current (CC)
Flux cored wires
To prevent drawing of liquid CO2 (Carbon Dioxide)

42. What is the maximum distance that hard wire can be successfully pushed?
Controls the rate of flow of a shielding gas to the gun nozzle
Compressed gas cylinder - Liquid filled cylinder - or a Liquid bulk system
Penetration and burn - off rate of the electrode
15 feet (4.5 meters)

43. What is the reason glass 'tube' type flowmeters must have the tube mounted truly vertical?
Dry ice can form within the flow control openings and cause blockage of shielding gas
SMAW - GTAW
...
Wire feed speed - Voltage control

44. What is the main purpose of 'slope'?
Electricaly operated valves that control the flow of shielding gas to the weld zone. The control switch located on the gun
To limit the short circuiting current so that spatter is reduced
1/4 inch to 1/2 inch
SMAW - GTAW

45. What does voltage do in an electrical circuit?
By there current carrying capacity
Voltage is the force that overcomes resistance to allow amperage flow
1/4 inch to 1/2 inch
Pressure vessels and the piping industry

46. What does the abbreviation NEMA stand for?
Penetration and burn - off rate of the electrode
Welding Current - Filler wire diameter - arc length - type of shielding - position of the weld
National Electrical Manufactures Association
To limit the short circuiting current so that spatter is reduced

47. Why must CO2 cylinders be used in the vertical position?
Welding Current - Filler wire diameter - arc length - type of shielding - position of the weld
Wire feed speed - Voltage control
V groove or U groove
To prevent drawing of liquid CO2 (Carbon Dioxide)

48. What is the key advantage of short circuiting transfer?
15 feet (4.5 meters)
5.8 to 12.5 L/min
DCEP (Direct Current Electrode Positive) Reverse Polarity
Minimum distortion due to low heat input

49. When is the metal transferred with short circuit transfer?
Insufficient current to melt the wire off cleanly
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
Short- circuiting transfer - Globular transfer - Spray transfer

50. What does the wire feeder control?
Speed of the feed motor and - starting / stopping electrode feed
Aluminum wire
3
Insufficient current to melt the wire off cleanly