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. 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
Increasing inductance increases puddle fluidity - improves penatration - makes the bead flatter and smoother - and reduces spatter. To much inductance though will create erratic starts
Minutes of elapsed time continually run (out of 10 minutes)
AWS and CSA

2. What power sources are used with the GMAW Process?
Minimum distortion due to low heat input
Constant current (CC)
Insufficient current to melt the wire off cleanly
Motor driven generators - Transformer rectifiers - and Inverter designs

3. 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
Controls the rate of flow of a shielding gas to the gun nozzle
Insufficient current to melt the wire off cleanly
Wire feed speed - Voltage control

4. List the factors that determine the mode of metal transfer
Welding Current - Filler wire diameter - arc length - type of shielding - position of the weld
The resistace to electrical current flow increases with it. Causing the electrode to heat
The Arc voltage
Wire feeds smoothly (yet will slip should a problem occur in the gun)

5. A pull type drive system is usually used on what type of material?
Insufficient current to melt the wire off cleanly
Penetration and burn - off rate of the electrode
Constant voltage (CV)
Aluminum wire

6. Give a brief description of the GMAW process
Spatter problems and poor weld appearance
Welding process that joins metals by heating them with an electric arc
The negative side of a welding unit
Power source - wire feeder - welding gun - Spooled filler wire - Shielding gas - and a ground

7. What does the term GMAW identify?
The negative side of a welding unit
V groove or U groove
Voltage is the force that overcomes resistance to allow amperage flow
Gas metal arc welding

8. 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
3
Generally not as accurate
Electricaly operated valves that control the flow of shielding gas to the weld zone. The control switch located on the gun

9. When is the metal transferred with short circuit transfer?
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
Penetration and burn - off rate of the electrode
Constant current (CC)

10. What happens when the electrode extension is increased?
Higher 26 to 35 arc volts
Penetration and burn - off rate of the electrode
The resistace to electrical current flow increases with it. Causing the electrode to heat
Minutes of elapsed time continually run (out of 10 minutes)

11. Draw a typical volt amp curve for a machine that is designed for GMAW
Reducing the gas source pressure to a constant working pressure
Controls the rate of flow of a shielding gas to the gun nozzle
If you dont know this check your phone
1/4 inch to 1/2 inch

12. What would be an indication that the drive roll pressure is adjusted correctly?
Wire feeds smoothly (yet will slip should a problem occur in the gun)
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
When the filler wire is in direct contract with the base metal
Puddle fluidity

13. What wire are knurled drive rolls most commonly used on?
Penetration and burn - off rate of the electrode
Dry ice can form within the flow control openings and cause blockage of shielding gas
The time rate of response for the current rise and fall
Flux cored wires

14. What is the recommended electrode stick- out for .035 solid wire?
1/4 inch to 1/2 inch
Speed of the feed motor and - starting / stopping electrode feed
Pressure - The rate of flow of a shielding gas
Insufficient current to melt the wire off cleanly

15. What is the minimum % value of argon that must be present to use the spray transfer method of GMAW?
85%
Wire feed speed - Voltage control
Increasing inductance increases puddle fluidity - improves penatration - makes the bead flatter and smoother - and reduces spatter. To much inductance though will create erratic starts
The time rate of response for the current rise and fall

16. What type of power source is commonly used with a voltage sensing wire feeder?
1/4 inch to 1/2 inch
Constant current (CC)
AWS and CSA
To prevent leakage - Carbon Dioxide (CO2)

17. What is the purpose of a regulator and what does it indicate on its gauges?
Pressure vessels and the piping industry
Reducing the gas source pressure to a constant working pressure
Power source - wire feeder - welding gun - Spooled filler wire - Shielding gas - and a ground
Controls the rate of flow of a shielding gas to the gun nozzle

18. What effect does increasing and decreasing the inductance have on the weld?
Guns
Welding Current - Filler wire diameter - arc length - type of shielding - position of the weld
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

19. List several industries that would use GMAW
Pressure vessels and the piping industry
Aluminum wire
1/4 inch to 1/2 inch
Molten metal is separated from the end of the filler wire by a squeezing force created by a magnetic field

20. What 2 controls are found on a GMAW set- up?
Shielding the molten weld metal from atmospheric contamination
To limit the short circuiting current so that spatter is reduced
Wire feed speed - Voltage control
15 feet (4.5 meters)

21. What is the main purpose of 'slope'?
Constant- speed wire feeders and Voltage- sennsing wire feeders
To limit the short circuiting current so that spatter is reduced
Minutes of elapsed time continually run (out of 10 minutes)
When the filler wire is in direct contract with the base metal

22. What is the maximum distance that hard wire can be successfully pushed?
SMAW - GTAW
Wire feed speed - Voltage control
15 feet (4.5 meters)
Molten metal is separated from the end of the filler wire by a squeezing force created by a magnetic field

23. What is the required arc voltage used for short circuit transfer?
Minutes of elapsed time continually run (out of 10 minutes)
12 to 22 arc volts
1/4 inch to 1/2 inch
Motor driven generators - Transformer rectifiers - and Inverter designs

24. What is a typical flow rate of CO2 for short circuit transfer?
Speed of the feed motor and - starting / stopping electrode feed
Shielding the molten weld metal from atmospheric contamination
5.8 to 12.5 L/min
Generally not as accurate

25. What processes are constant current (CC) power sources designed to be used with?
Speed of the feed motor and - starting / stopping electrode feed
SMAW - GTAW
85%
Aluminum wire

26. What is the purpose of the shielding gas used in GMAW?
Welding Current - Filler wire diameter - arc length - type of shielding - position of the weld
Shielding the molten weld metal from atmospheric contamination
Dry ice can form within the flow control openings and cause blockage of shielding gas
Controls the rate of flow of a shielding gas to the gun nozzle

27. List 3 wire drive systems and give a short description of each
AWS and CSA
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
Puddle fluidity
The Arc voltage

28. What output on the welding machine is used to rate the duty cycle?
SMAW - GTAW
Minutes of elapsed time continually run (out of 10 minutes)
15 feet (4.5 meters)
V groove or U groove

29. List 3 forms compressed gases may be supplied for welding
The time rate of response for the current rise and fall
Reducing the gas source pressure to a constant working pressure
Compressed gas cylinder - Liquid filled cylinder - or a Liquid bulk system
To limit the short circuiting current so that spatter is reduced

30. Draw a typical volt/amp curve that would be found with a power source designed for SMAW or GTAW
20 to 200 times per second
The time rate of response for the current rise and fall
If you dont know this check your phone
Flux cored wires

31. What does voltage do in an electrical circuit?
Generally not as accurate
Reducing the gas source pressure to a constant working pressure
Motor driven generators - Transformer rectifiers - and Inverter designs
Voltage is the force that overcomes resistance to allow amperage flow

32. What does the abbreviation NEMA stand for?
Voltage is the force that overcomes resistance to allow amperage flow
National Electrical Manufactures Association
Pressure vessels and the piping industry
Compressed gas cylinder - Liquid filled cylinder - or a Liquid bulk system

33. What current and polarity is generally used with GMAW?
SMAW - GTAW
Penetration and burn - off rate of the electrode
DCEP (Direct Current Electrode Positive) Reverse Polarity
Minutes of elapsed time continually run (out of 10 minutes)

34. With straight polarity where is 2/3 of the arc energy?
Cause flaking - which can clog the liner and contact tube
The negative side of a welding unit
12 to 22 arc volts
Voltage is the force that overcomes resistance to allow amperage flow

35. What is the reason glass 'tube' type flowmeters must have the tube mounted truly vertical?
...
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
Speed of the feed motor and - starting / stopping electrode feed
Reducing the gas source pressure to a constant working pressure

36. What is an advantage of pulsed arc transfer with GMAW?
Compressed gas cylinder - Liquid filled cylinder - or a Liquid bulk system
Heat input is less than spray transfer - resulting in less distortion - Used in all positions due to controlling the weld metal freeze
Controls the rate of flow of a shielding gas to the gun nozzle
Pressure vessels and the piping industry

37. Regulators control_____________ flowmeters SHOW____________.
Puddle fluidity
When the filler wire is in direct contract with the base metal
Pressure - The rate of flow of a shielding gas
...

38. What are the 2 types of wire feeders available?
Minutes of elapsed time continually run (out of 10 minutes)
Gives arc voltage values to the control system of the feeder
Constant- speed wire feeders and Voltage- sennsing wire feeders
Insufficient current to melt the wire off cleanly

39. Why must CO2 cylinders be used in the vertical position?
Wire feed speed
Guns
To prevent drawing of liquid CO2 (Carbon Dioxide)
Voltage is the force that overcomes resistance to allow amperage flow

40. How are GMAW guns rated?
Pressure vessels and the piping industry
Generally not as accurate
By there current carrying capacity
Minutes of elapsed time continually run (out of 10 minutes)

41. A machine with a 70% duty cycle can run at its max for 7 minutes with a cooling cycle of only _ minutes.
Power source - wire feeder - welding gun - Spooled filler wire - Shielding gas - and a ground
Pressure vessels and the piping industry
3
15 feet (4.5 meters)

42. What is another term for electrode holders for GMAW?
Guns
To prevent leakage - Carbon Dioxide (CO2)
3
These terms are quite restrictive and often technically incorrect

43. What does inductance control?
National Electrical Manufactures Association
Short- circuiting transfer - Globular transfer - Spray transfer
Reducing the gas source pressure to a constant working pressure
The time rate of response for the current rise and fall

44. How many times per second does short circuiting take place?
(DCEP) Direct Current Electrode Positive or Reverse polarity
Generally not as accurate
20 to 200 times per second
Increasing inductance increases puddle fluidity - improves penatration - makes the bead flatter and smoother - and reduces spatter. To much inductance though will create erratic starts

45. Why is a fiber washer required and what cylinder gas requires it?
Gives arc voltage values to the control system of the feeder
To prevent leakage - Carbon Dioxide (CO2)
Minutes of elapsed time continually run (out of 10 minutes)
Spatter problems and poor weld appearance

46. Why is the term GMAW preferred over MIG or MAG?
Minutes of elapsed time continually run (out of 10 minutes)
85%
12 to 22 arc volts
These terms are quite restrictive and often technically incorrect

47. What is the preferred drive roll design for solid wires?
Heat input is less than spray transfer - resulting in less distortion - Used in all positions due to controlling the weld metal freeze
(DCEP) Direct Current Electrode Positive or Reverse polarity
These terms are quite restrictive and often technically incorrect
V groove or U groove

48. What is a solenoid valve and what actuates it?
Constant voltage (CV)
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
Molten metal is separated from the end of the filler wire by a squeezing force created by a magnetic field

49. List the three methods of metal transfer with GMAW
Flux cored wires
Generally not as accurate
12 to 22 arc volts
Short- circuiting transfer - Globular transfer - Spray transfer

50. What is the key advantage of short circuiting transfer?
Dry ice can form within the flow control openings and cause blockage of shielding gas
Minimum distortion due to low heat input
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