Chapter 1 Welding Processes and Equipment Flashcards Preview

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Flashcards in Chapter 1 Welding Processes and Equipment Deck (35)
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1
Q
  1. An arc plasma consists of

a. atoms and gas molecules.
b. free electrons and posifive ions.
C. Carbon atoms and hydrogen molecules.
d. light of a fixed wavelength

A

b. free electrons and posifive ions.

2
Q
  1. Which of the following welding processes is the most commonly used?

a. Resistance Welding
b. Blazing
c. Solid State Welding
d. Arc Welding

A

d. Arc Welding

3
Q
  1. The most arc efficient welding process is the _______ process.

a. GTAW
b. SMAW
c. FCAW
d. SAW

A

d. SAW

4
Q
  1. Which two areas represent the largest voltage drop in a welding arc?

a. Electrode extension and Cathode drop zone
b. Electrode extension and Anode drop zone
c. Arc plasma and electrode extension
d. Cathode drop zone and Anode drop zone

A

d. Cathode drop zone and Anode drop zone

5
Q
  1. The pinch force that aids in droplet detachment during spray transfer is produced by

a. a self—induced magnetic field
b. gravity
c. surface tension
d. the plasma jet

A

a. a self—induced magnetic field

6
Q
  1. Which of the following welding processes produces the least hydrogen weld metal content?

a. SMAW
b. GTAW
c. SAW
d. FCAW

A

b. GTAW

7
Q
  1. The majority of the arc energy is transferred to the work when the GTAW process is operated in
    polarity.

a. AC
b. DCEP
c. DCEN
d. AC unbalanced

A

c. DCEN

8
Q
  1. Modern inverter GTAW power sources use all methods for arc starting, except for?

a. Scratch
b. High Frequency
c. Steel Wool
d. Electronic Touch

A

c. Steel Wool

9
Q
  1. The highest deposition rate in the SMAW process occurs in

a. DCEN
b. DCEP
c. AC
d. AC unbalanced

A

a. DCEN

10
Q
  1. The arc force control in CC welding power sources is used to ___________ in the SMAW process.

a. reduce the penetration of the weld when the arc length is decreased
b. increase the penetration of the weld when the arc length is decreased
c. reduce the penetration of the weld when the arc length is increased
d. increase the penetration of the weld when the arc length is increased

A

b. increase the penetration of the weld when the arc length is decreased

11
Q
  1. The function of the ingredients within the electrode coating of SMAW electrodes is to:

a. provide gas shielding, provide slag cover, scavenge impurities, stabilize the arc and adding alloy elements
b. aid in the weld metal wetting the base metal
c. reduce arc blow
d. conduct a portion of the arc current

A

a. provide gas shielding, provide slag cover, scavenge impurities, stabilize the arc and adding alloy elements

12
Q
  1. The electrodes represented by EXX15, EXX16, and EXX18 have _________as a major ingredient in the coating.

a. limestone
b. cellulose
c. titania
d. none of the above

A

a. limestone

13
Q
  1. The GMAW, FCAW and MCAW processes have these features in common.

a. Constant current power source and constant speed wire feeder
b. Constant voltage power source and constant speed wire feeder
c. Constant current power source and variable speed wire feeder
d. Constant voltage power source and variable speed wire feeder

A

b. Constant voltage power source and constant speed wire feeder

14
Q
  1. The welding current in the GMAW process is determined by which of the following variables?

a. Wire feed speed
b. Voltage
c. Contact tube to work distance
d. Arc travel speed

A

a. Wire feed speed

15
Q
  1. What are the two power source variables that can be used to control spatter in GMAW short circuit transfer.

a. Voltage and current
b. Input voltage and number of phases
c. Arc force and static characteristic
d. Inductance and static characteristic

A

d. Inductance and static characteristic

16
Q
  1. Which of the GMAW metal transfer modes can be used to weld out of position?

a. Globular and spray
b. Short circuit and pulsed
c. Short circuit and globular
d. Spray and pulsed

A

b. Short circuit and pulsed

17
Q
  1. The shielding gas used in the GMAW process to produce short circuit transfer is

a. argon
b. argon with 15% carbon dioxide
c. helium
d. carbon dioxide

A

d. carbon dioxide

18
Q
  1. Which shielding gas produces the most pronounced finger penetration for the GMAW process?

a. Argon with 2% oxygen
b. Argon with 5% carbon dioxide
c. Argon with 25% carbon dioxide
d. Carbon dioxide

A

a. Argon with 2% oxygen

19
Q
  1. Which of the following statements is incorrect?

a. At a specific welding current and wire size the FCAW process has a higher deposition rate than the GMAW process.
b. It is easier to change the chemical composition of the weld with the FCAW process compared to the GMAW process
c. Just a) above
d. a) and b) above

A

d. a) and b) above

20
Q
  1. Which type of weld metal transfer is produced using 75% argon and 25% carbon dioxide shielding gas using high currents and basic fluxed cored wires?

a. Spray
b. Globular
c. Short circuit
d. Dip

A

a. Spray

21
Q
  1. Compared with the FCAW process the MCAW process has the following features.

a. Higher deposition rates for the same electrode size and current
b. Typically only used in the flat and horizontal position
c. Higher productivity because there is only islanding slag produced
d. All of the above

A

d. All of the above

22
Q
  1. Worm tracks produced using the FCAW process can be avoided by

a. using carbon dioxide shielding gas
b. increasing the contact tube to work distance
c. decreasing current and voltage
d. all of the above

A

d. all of the above

23
Q
  1. The submerged arc welding process incorporates

a. a continuously fed tubular wire and a constant current power source and a buried arc
b. a continuous fed solid wire and a constant voltage power source and the arc covered by flux
c. a small continuously fed solid wire and a constant current power source and the arc covered by flux
d. a large continuously fed solid wire and a constant voltage power source and the arc covered by flux

A

b. a continuous fed solid wire and a constant voltage power source and the arc covered by flux

24
Q
  1. The tandem SAW process typically involves:

a. two wire feeders and one DC and one AC power source
b. two wire feeders and two constant voltage DC power sources
c. one wire feeder with two wires and one DC power source
d. two wire feeders and two DC power sources

A

a. two wire feeders and one DC and one AC power source

25
Q
  1. The twin wire SAW process involves:

a. two wire feeders and one DC and one AC power source
b. two wire feeders and two constant voltage DC power sources
c. one wire feeder with two wires and one DC power source
d. two wire feeders and two DC power sources

A

c. one wire feeder with two wires and one DC power source

26
Q
  1. ___________ is common weld defect that can occur when using high current DCEP polarity for the SAW process.

a. Undercut
b. Underfill
c. Slag entrapment
d. Solidification cracking

A

d. Solidification cracking

27
Q
  1. For the SAW process the wires and fluxes can be selected to

a. achieve high deposition rates
b. achieve high travel speeds
c. achieve specific mechanical properties
d. all of the above

A

d. all of the above

28
Q
  1. Which current type produces the most consistent penetration using SAW process?

a. A constant voltage power source and variable speed wire feeder
b. A constant voltage power source and constant speed wire feeder
c. A constant current power source and variable speed wire feeder
d. A constant current power source and constant speed wire feeder

A

c. A constant current power source and variable speed wire feeder

29
Q
  1. The main controllable process variables for the resistance welding process are

a. current, pressure and tlme
b. electrode size, pressure, current and time
c. base metal, current, time, and pressure
d. base metal, current and time

A

b. electrode size, pressure, current and time

30
Q
  1. The purpose of a brazing flux is to

a. remove oxides and reduce the surface tension of the molten filler
b. clean contaminants from the joint
c. lower the melting temperature of the filler
d. open the joint to allow room for the filler

A

a. remove oxides and reduce the surface tension of the molten filler

31
Q
  1. In the PAW process, the keyhole plasma on 6 mm thick material has a current range of greater than

a. 50 amps
b. 100 amps
c. 1000 amps
d. 500 amps

A

b. 100 amps

32
Q

What is the Arc Efficiency for SAW?

A

90-95%

33
Q

What is the Arc Efficiency for SMAW,GMAW,FCAW?

A

65-85%

34
Q

What is the Arc Efficiency for GTAW?

A

20-45%

35
Q

What happens when the electrode melts?

A
  • surface tension
  • gravity
  • plasma jet
  • electromagnetic pinch force