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. Why must CO2 cylinders be used in the vertical position?
Welding process that joins metals by heating them with an electric arc
To prevent drawing of liquid CO2 (Carbon Dioxide)
Minimum distortion due to low heat input
By there current carrying capacity

2. Draw a typical volt/amp curve that would be found with a power source designed for SMAW or GTAW
Constant current (CC)
Increasing inductance increases puddle fluidity - improves penatration - makes the bead flatter and smoother - and reduces spatter. To much inductance though will create erratic starts
When the filler wire is in direct contract with the base metal
If you dont know this check your phone

3. Regulators control_____________ flowmeters SHOW____________.
Pressure - The rate of flow of a shielding gas
V groove or U groove
Penetration and burn - off rate of the electrode
Constant- speed wire feeders and Voltage- sennsing wire feeders

4. What is the purpose of the shielding gas used in GMAW?
Higher 26 to 35 arc volts
Shielding the molten weld metal from atmospheric contamination
Spatter problems and poor weld appearance
Constant- speed wire feeders and Voltage- sennsing wire feeders

5. List 3 wire drive systems and give a short description of each
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 negative side of a welding unit
85%
Constant voltage (CV)

6. What is the reason glass 'tube' type flowmeters must have the tube mounted truly vertical?
Short- circuiting transfer - Globular transfer - Spray transfer
15 feet (4.5 meters)
...
Spatter problems and poor weld appearance

7. What does the term GMAW identify?
(DCEP) Direct Current Electrode Positive or Reverse polarity
Gas metal arc welding
Constant voltage (CV)
Puddle fluidity

8. What is a typical flow rate of CO2 for short circuit transfer?
To limit the short circuiting current so that spatter is reduced
Flux cored wires
5.8 to 12.5 L/min
Penetration and burn - off rate of the electrode

9. What 2 controls are found on a GMAW set- up?
Gives arc voltage values to the control system of the feeder
Flux cored wires
Wire feed speed - Voltage control
20 to 200 times per second

10. What controls amperage when using GMAW?
15 feet (4.5 meters)
The resistace to electrical current flow increases with it. Causing the electrode to heat
Wire feed speed
Constant current (CC)

11. 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
Insufficient current to melt the wire off cleanly
Pressure - The rate of flow of a shielding gas
Guns

12. Draw a typical volt amp curve for a machine that is designed for GMAW
If you dont know this check your phone
85%
National Electrical Manufactures Association
Voltage is the force that overcomes resistance to allow amperage flow

13. What is the purpose of the pick- up lead on a voltage sensing wire feeder?
Minutes of elapsed time continually run (out of 10 minutes)
Wire feed speed - Voltage control
Gives arc voltage values to the control system of the feeder
When the filler wire is in direct contract with the base metal

14. A machine with a 70% duty cycle can run at its max for 7 minutes with a cooling cycle of only _ minutes.
The resistace to electrical current flow increases with it. Causing the electrode to heat
15 feet (4.5 meters)
Gives arc voltage values to the control system of the feeder
3

15. What is an advantage of pulsed arc transfer with GMAW?
5.8 to 12.5 L/min
Heat input is less than spray transfer - resulting in less distortion - Used in all positions due to controlling the weld metal freeze
Short- circuiting transfer - Globular transfer - Spray transfer
The resistace to electrical current flow increases with it. Causing the electrode to heat

16. What is the preferred drive roll design for solid wires?
Controls the rate of flow of a shielding gas to the gun nozzle
These terms are quite restrictive and often technically incorrect
V groove or U groove
National Electrical Manufactures Association

17. 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
Gas metal arc welding
Wire feed speed - Voltage control
National Electrical Manufactures Association

18. A pull type drive system is usually used on what type of material?
Puddle fluidity
Aluminum wire
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

19. What does voltage do in an electrical circuit?
To limit the short circuiting current so that spatter is reduced
Voltage is the force that overcomes resistance to allow amperage flow
The negative side of a welding unit
Speed of the feed motor and - starting / stopping electrode feed

20. What does inductance control?
12 to 22 arc volts
To prevent leakage - Carbon Dioxide (CO2)
Insufficient current to melt the wire off cleanly
The time rate of response for the current rise and fall

21. In the GMAW process what does amperage control?
3
Penetration and burn - off rate of the electrode
Insufficient current to melt the wire off cleanly
Spatter problems and poor weld appearance

22. With straight polarity where is 2/3 of the arc energy?
The negative side of a welding unit
5.8 to 12.5 L/min
1/4 inch to 1/2 inch
National Electrical Manufactures Association

23. What is another term for electrode holders for GMAW?
Guns
Constant- speed wire feeders and Voltage- sennsing wire feeders
Wire feed speed - Voltage control
Flux cored wires

24. What are the 2 types of wire feeders available?
National Electrical Manufactures Association
Pressure - The rate of flow of a shielding gas
Constant- speed wire feeders and Voltage- sennsing wire feeders
Minimum distortion due to low heat input

25. What controls the wire speed on a voltage sensing wire feeder?
Controls the rate of flow of a shielding gas to the gun nozzle
The Arc voltage
3
The negative side of a welding unit

26. What type of power source is used with a constant speed wire feeder?
Welding Current - Filler wire diameter - arc length - type of shielding - position of the weld
Spatter problems and poor weld appearance
Constant voltage (CV)
National Electrical Manufactures Association

27. What power sources are used with the GMAW Process?
The Arc voltage
Motor driven generators - Transformer rectifiers - and Inverter designs
By there current carrying capacity
If you dont know this check your phone

28. What is the disadvantage of the gauge preset type of regulator/flowmeter?
DCEP (Direct Current Electrode Positive) Reverse Polarity
Speed of the feed motor and - starting / stopping electrode feed
National Electrical Manufactures Association
Generally not as accurate

29. What does the abbreviation NEMA stand for?
National Electrical Manufactures Association
Motor driven generators - Transformer rectifiers - and Inverter designs
Gas metal arc welding
If you dont know this check your phone

30. List the factors that determine the mode of metal transfer
Welding Current - Filler wire diameter - arc length - type of shielding - position of the weld
By there current carrying capacity
Pressure vessels and the piping industry
Wire feed speed - Voltage control

31. List the basic equipment requirements for the GMAW process
Generally not as accurate
The negative side of a welding unit
Voltage is the force that overcomes resistance to allow amperage flow
Power source - wire feeder - welding gun - Spooled filler wire - Shielding gas - and a ground

32. What is the minimum % value of argon that must be present to use the spray transfer method of GMAW?
Cause flaking - which can clog the liner and contact tube
Guns
85%
When the filler wire is in direct contract with the base metal

33. How many times per second does short circuiting take place?
Higher 26 to 35 arc volts
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
When the filler wire is in direct contract with the base metal

34. A 10 minute cycle of welding time vs cooling time a given machine can handle.
Generally not as accurate
Minimum distortion due to low heat input
Speed of the feed motor and - starting / stopping electrode feed
Duty cycle

35. What is the recommended electrode stick- out for .035 solid wire?
1/4 inch to 1/2 inch
85%
Penetration and burn - off rate of the electrode
Welding process that joins metals by heating them with an electric arc

36. What current and polarity is generally used with GMAW?
DCEP (Direct Current Electrode Positive) Reverse Polarity
Cause flaking - which can clog the liner and contact tube
If you dont know this check your phone
Wire feed speed - Voltage control

37. What processes are constant current (CC) power sources designed to be used with?
...
National Electrical Manufactures Association
SMAW - GTAW
Cause flaking - which can clog the liner and contact tube

38. List 3 forms compressed gases may be supplied for welding
Constant- speed wire feeders and Voltage- sennsing wire feeders
If you dont know this check your phone
Compressed gas cylinder - Liquid filled cylinder - or a Liquid bulk system
Increasing inductance increases puddle fluidity - improves penatration - makes the bead flatter and smoother - and reduces spatter. To much inductance though will create erratic starts

39. What wire are knurled drive rolls most commonly used on?
Generally not as accurate
If you dont know this check your phone
Flux cored wires
The time rate of response for the current rise and fall

40. List several industries that would use GMAW
Duty cycle
Motor driven generators - Transformer rectifiers - and Inverter designs
Pressure vessels and the piping industry
Penetration and burn - off rate of the electrode

41. In the GMAW process what does voltage control?
Heat input is less than spray transfer - resulting in less distortion - Used in all positions due to controlling the weld metal freeze
Puddle fluidity
Minutes of elapsed time continually run (out of 10 minutes)
If you dont know this check your phone

42. What is the purpose of a regulator and what does it indicate on its gauges?
Speed of the feed motor and - starting / stopping electrode feed
3
Reducing the gas source pressure to a constant working pressure
Power source - wire feeder - welding gun - Spooled filler wire - Shielding gas - and a ground

43. What output on the welding machine is used to rate the duty cycle?
Increasing inductance increases puddle fluidity - improves penatration - makes the bead flatter and smoother - and reduces spatter. To much inductance though will create erratic starts
To prevent drawing of liquid CO2 (Carbon Dioxide)
AWS and CSA
Minutes of elapsed time continually run (out of 10 minutes)

44. Give a description of 'pinch effect'
National Electrical Manufactures Association
Molten metal is separated from the end of the filler wire by a squeezing force created by a magnetic field
Power source - wire feeder - welding gun - Spooled filler wire - Shielding gas - and a ground
Electricaly operated valves that control the flow of shielding gas to the weld zone. The control switch located on the gun

45. What term is used to describe when the workpiece is hooked to the negative pole on the power source?
Cause flaking - which can clog the liner and contact tube
(DCEP) Direct Current Electrode Positive or Reverse polarity
Puddle fluidity
Constant voltage (CV)

46. How are GMAW guns rated?
Pressure vessels and the piping industry
Dry ice can form within the flow control openings and cause blockage of shielding gas
By there current carrying capacity
If you dont know this check your phone

47. Why is a fiber washer required and what cylinder gas requires it?
Welding Current - Filler wire diameter - arc length - type of shielding - position of the weld
Electricaly operated valves that control the flow of shielding gas to the weld zone. The control switch located on the gun
1/4 inch to 1/2 inch
To prevent leakage - Carbon Dioxide (CO2)

48. What does the wire feeder control?
Speed of the feed motor and - starting / stopping electrode feed
Puddle fluidity
Constant current (CC)
Voltage is the force that overcomes resistance to allow amperage flow

49. What 2 organizations designate specifications for GMAW wires?
Duty cycle
AWS and CSA
These terms are quite restrictive and often technically incorrect
Constant current (CC)

50. What is the effect of too much slope?
Insufficient current to melt the wire off cleanly
12 to 22 arc volts
Heat input is less than spray transfer - resulting in less distortion - Used in all positions due to controlling the weld metal freeze
Gas metal arc welding