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Test your basic knowledge |
Gas Metal Arc Welding
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Subject
:
engineering
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 another term for electrode holders for GMAW?
Guns
To limit the short circuiting current so that spatter is reduced
Wire feeds smoothly (yet will slip should a problem occur in the gun)
Wire feed speed - Voltage control
2. List 3 wire drive systems and give a short description of each
(DCEP) Direct Current Electrode Positive or Reverse polarity
1/4 inch to 1/2 inch
Voltage is the force that overcomes resistance to allow amperage flow
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
3. Is the arc voltage for spray transfer higher or lower than that used for short circuit transfer?
Aluminum wire
Higher 26 to 35 arc volts
Minutes of elapsed time continually run (out of 10 minutes)
Insufficient current to melt the wire off cleanly
4. What is the minimum % value of argon that must be present to use the spray transfer method of GMAW?
85%
15 feet (4.5 meters)
Cause flaking - which can clog the liner and contact tube
Pressure vessels and the piping industry
5. What is an advantage of pulsed arc transfer with GMAW?
Guns
Welding process that joins metals by heating them with an electric arc
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
6. What is the purpose of the pick- up lead on a voltage sensing wire feeder?
To limit the short circuiting current so that spatter is reduced
Dry ice can form within the flow control openings and cause blockage of shielding gas
3
Gives arc voltage values to the control system of the feeder
7. Why is globular transfer generally avoided with GMAW?
20 to 200 times per second
Spatter problems and poor weld appearance
By there current carrying capacity
The Arc voltage
8. List 3 forms compressed gases may be supplied for welding
Compressed gas cylinder - Liquid filled cylinder - or a Liquid bulk system
Molten metal is separated from the end of the filler wire by a squeezing force created by a magnetic field
Generally not as accurate
By there current carrying capacity
9. What is the purpose of the shielding gas used in 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
These terms are quite restrictive and often technically incorrect
To prevent drawing of liquid CO2 (Carbon Dioxide)
Shielding the molten weld metal from atmospheric contamination
10. How are GMAW guns rated?
85%
Constant current (CC)
Guns
By there current carrying capacity
11. What is the key advantage of short circuiting transfer?
Minimum distortion due to low heat input
...
Duty cycle
DCEP (Direct Current Electrode Positive) Reverse Polarity
12. What current and polarity is generally used with GMAW?
5.8 to 12.5 L/min
Flux cored wires
Constant- speed wire feeders and Voltage- sennsing wire feeders
DCEP (Direct Current Electrode Positive) Reverse Polarity
13. What is the preferred drive roll design for solid wires?
The Arc voltage
V groove or U groove
Constant voltage (CV)
Welding Current - Filler wire diameter - arc length - type of shielding - position of the weld
14. Why must CO2 cylinders be used in the vertical position?
To prevent drawing of liquid CO2 (Carbon Dioxide)
SMAW - GTAW
Controls the rate of flow of a shielding gas to the gun nozzle
The resistace to electrical current flow increases with it. Causing the electrode to heat
15. What is the purpose of a regulator and what does it indicate on its gauges?
Power source - wire feeder - welding gun - Spooled filler wire - Shielding gas - and a ground
Duty cycle
Reducing the gas source pressure to a constant working pressure
3
16. What does the abbreviation NEMA stand for?
National Electrical Manufactures Association
Duty cycle
Penetration and burn - off rate of the electrode
Insufficient current to melt the wire off cleanly
17. What output on the welding machine is used to rate the duty cycle?
...
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
Minutes of elapsed time continually run (out of 10 minutes)
By there current carrying capacity
18. 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
National Electrical Manufactures Association
Constant voltage (CV)
Motor driven generators - Transformer rectifiers - and Inverter designs
19. Regulators control_____________ flowmeters SHOW____________.
Spatter problems and poor weld appearance
Speed of the feed motor and - starting / stopping electrode feed
Pressure - The rate of flow of a shielding gas
Wire feed speed
20. List several industries that would use GMAW
(DCEP) Direct Current Electrode Positive or Reverse polarity
Pressure vessels and the piping industry
12 to 22 arc volts
Wire feeds smoothly (yet will slip should a problem occur in the gun)
21. In the GMAW process what does voltage control?
Puddle fluidity
V groove or U groove
15 feet (4.5 meters)
Penetration and burn - off rate of the electrode
22. With straight polarity where is 2/3 of the arc energy?
The negative side of a welding unit
Flux cored wires
Minimum distortion due to low heat input
By there current carrying capacity
23. What wire are knurled drive rolls most commonly used on?
Guns
Electricaly operated valves that control the flow of shielding gas to the weld zone. The control switch located on the gun
Flux cored wires
Constant voltage (CV)
24. What is the required arc voltage used for short circuit transfer?
12 to 22 arc volts
To prevent leakage - Carbon Dioxide (CO2)
Molten metal is separated from the end of the filler wire by a squeezing force created by a magnetic field
Puddle fluidity
25. Draw a typical volt amp curve for a machine that is designed for GMAW
15 feet (4.5 meters)
If you dont know this check your phone
Pressure vessels and the piping industry
DCEP (Direct Current Electrode Positive) Reverse Polarity
26. What is a typical flow rate of CO2 for short circuit transfer?
5.8 to 12.5 L/min
Gas metal arc welding
Pressure - The rate of flow of a shielding gas
Insufficient current to melt the wire off cleanly
27. A pull type drive system is usually used on what type of material?
Voltage is the force that overcomes resistance to allow amperage flow
Constant- speed wire feeders and Voltage- sennsing wire feeders
Speed of the feed motor and - starting / stopping electrode feed
Aluminum wire
28. What is the main purpose of 'slope'?
Insufficient current to melt the wire off cleanly
To limit the short circuiting current so that spatter is reduced
Increasing inductance increases puddle fluidity - improves penatration - makes the bead flatter and smoother - and reduces spatter. To much inductance though will create erratic starts
Heat input is less than spray transfer - resulting in less distortion - Used in all positions due to controlling the weld metal freeze
29. What type of power source is used with a constant speed wire feeder?
Constant voltage (CV)
SMAW - GTAW
Dry ice can form within the flow control openings and cause blockage of shielding gas
These terms are quite restrictive and often technically incorrect
30. What processes are constant current (CC) power sources designed to be used with?
SMAW - GTAW
Pressure vessels and the piping industry
Welding Current - Filler wire diameter - arc length - type of shielding - position of the weld
Compressed gas cylinder - Liquid filled cylinder - or a Liquid bulk system
31. What controls the wire speed on a voltage sensing wire feeder?
Generally not as accurate
Guns
Flux cored wires
The Arc voltage
32. What effect does increasing and decreasing the inductance have on the weld?
The Arc voltage
These terms are quite restrictive and often technically incorrect
Short- circuiting transfer - Globular transfer - Spray transfer
Increasing inductance increases puddle fluidity - improves penatration - makes the bead flatter and smoother - and reduces spatter. To much inductance though will create erratic starts
33. What is the recommended electrode stick- out for .035 solid wire?
The resistace to electrical current flow increases with it. Causing the electrode to heat
1/4 inch to 1/2 inch
85%
Constant- speed wire feeders and Voltage- sennsing wire feeders
34. 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
5.8 to 12.5 L/min
If you dont know this check your phone
Gas metal arc welding
35. What term is used to describe when the workpiece is hooked to the negative pole on the power source?
Puddle fluidity
(DCEP) Direct Current Electrode Positive or Reverse polarity
V groove or U groove
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
36. Why is a line heater required when using GMAW?
20 to 200 times per second
SMAW - GTAW
Dry ice can form within the flow control openings and cause blockage of shielding gas
If you dont know this check your phone
37. What does the term GMAW identify?
If you dont know this check your phone
Voltage is the force that overcomes resistance to allow amperage flow
Guns
Gas metal arc welding
38. What 2 controls are found on a GMAW set- up?
Gives arc voltage values to the control system of the feeder
Wire feed speed - Voltage control
Electricaly operated valves that control the flow of shielding gas to the weld zone. The control switch located on the gun
Minutes of elapsed time continually run (out of 10 minutes)
39. What 2 organizations designate specifications for GMAW wires?
Welding process that joins metals by heating them with an electric arc
AWS and CSA
5.8 to 12.5 L/min
Compressed gas cylinder - Liquid filled cylinder - or a Liquid bulk system
40. A 10 minute cycle of welding time vs cooling time a given machine can handle.
Constant- speed wire feeders and Voltage- sennsing wire feeders
Duty cycle
Shielding the molten weld metal from atmospheric contamination
AWS and CSA
41. What happens when the electrode extension is increased?
Pressure - The rate of flow of a shielding gas
...
The resistace to electrical current flow increases with it. Causing the electrode to heat
To prevent leakage - Carbon Dioxide (CO2)
42. What power sources are used with the GMAW Process?
Electricaly operated valves that control the flow of shielding gas to the weld zone. The control switch located on the gun
These terms are quite restrictive and often technically incorrect
Motor driven generators - Transformer rectifiers - and Inverter designs
Aluminum wire
43. What is the reason glass 'tube' type flowmeters must have the tube mounted truly vertical?
...
To limit the short circuiting current so that spatter is reduced
Constant- speed wire feeders and Voltage- sennsing wire feeders
The resistace to electrical current flow increases with it. Causing the electrode to heat
44. What is the maximum distance that hard wire can be successfully pushed?
Minimum distortion due to low heat input
15 feet (4.5 meters)
The resistace to electrical current flow increases with it. Causing the electrode to heat
Molten metal is separated from the end of the filler wire by a squeezing force created by a magnetic field
45. Draw a typical volt/amp curve that would be found with a power source designed for SMAW or GTAW
If you dont know this check your phone
Controls the rate of flow of a shielding gas to the gun nozzle
20 to 200 times per second
To limit the short circuiting current so that spatter is reduced
46. Give a brief description of the GMAW process
To prevent drawing of liquid CO2 (Carbon Dioxide)
Constant current (CC)
Welding process that joins metals by heating them with an electric arc
20 to 200 times per second
47. What type of power source is commonly used with a voltage sensing wire feeder?
3
Electricaly operated valves that control the flow of shielding gas to the weld zone. The control switch located on the gun
Constant current (CC)
Constant voltage (CV)
48. How many times per second does short circuiting take place?
20 to 200 times per second
Pressure vessels and the piping industry
12 to 22 arc volts
The negative side of a welding unit
49. Why is a fiber washer required and what cylinder gas requires it?
Penetration and burn - off rate of the electrode
DCEP (Direct Current Electrode Positive) Reverse Polarity
To prevent leakage - Carbon Dioxide (CO2)
If you dont know this check your phone
50. What does inductance control?
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
The time rate of response for the current rise and fall
Wire feed speed - Voltage control
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