P10-2 task 1

Question 1

match the weld bead configuration shown in Figure 1 with the type of current listed below

1. _____ AC
2. _____ DCEP
3. _____ DCEN

Answer 1

1. ___c__ AC
2. ___b__ DCEP
3. ___a__ DCEN

Question 2

welding with DCEN concentrates at greater proportion of heat in the

1. workpiece
2. shielding gas
3. tungsten electrode
4. collet

Answer 2

a. workpiece

Question 3

welding with DCEP concentrates a greater proportion of the heat in the

1. workpiece
2. shielding gas
3. tungsten electrode
4. collet

Answer 3

c. tungsten electrode

Question 4

which type of current produces a strong cleaning action?

1. DCEN
2. DCEP
3. AC
4. pulsed current

Answer 4

b. DCEP

Question 5

which type of current produces greater penetration?

1. DCEN
2. DCEP

Answer 5

a. DCEN

Question 6

which type of current allows for the use of smaller diameter electrodes?

1. DCEN
2. DCEP

Answer 6

a. DCEN

Question 7

what is necessary to stabilize the arc when AC is used?

1. pulsed current
2. refractory circuit
3. high-frequency current
4. shielding gases

Answer 7

c. high-frequency current

Question 8

with AC which ½ cycle is lost?

1. DCEP
2. DCEN
3. amp-watt
4. amp-volt

Answer 8

a. DCEP

Question 9

identify three functions of high-frequency current in GTAW.

Answer 9

• “non-touch” starting method
• ensures ark re-ignition
• strengthens positive side of AC cycle

Question 10

when you use high-frequency current you can limit interference from radio signals by

1. suspending the welding cables above ground
2. using lower amperages
3. using long cables
4. ensuring the power source is properly grounded

Answer 10

d. ensuring the power source is properly grounded

Question 11

which type of current was developed in order to promote greater control over the heat input on the size of the weld puddle?

1. remote current
2. high-frequency current
3. pulsed current
4. inverted current

Answer 11

c. pulsed current

Question 12

pulsed current is particularly effective for welding

1. thin materials
2. in the vertical and overhead positions
3. refractory Metals
4. both A and C
5. both A and B

Answer 12

e. both A and B

Question 13

the control that triggers the flow of shielding gas before the arc is struct is called the

1. up slope
2. down slope
3. pre-purge
4. post-purge

Answer 13

c. pre-purge

Question 14

the setting them in teams the flow of shielding gas after welding is completed is called the

1. pre-purge
2. post-purge
3. up slope
4. down slope

Answer 14

b. post-purge

Question 15

the control used to initiate the current at a lower amperage than the welding current is called the

1. pre-purge
2. post-purge
3. up slope
4. down slope

Answer 15

c. up slope