Review Questions - Special Processes

Question 1

Electric resistance welding:

1. requires that mating surfaces be etched clean to produce a bond
2. requires that current flows through the workpieces
3. requires high voltage to overcome the electrode gap
4. requires high resistance between the electrodes and the workpiece

Answer 1

requires that current flows through the workpieces

Question 2

When resistance spot welding, why is the electrode force held after welding current ceases to flow?

1. to shield the weld nugget surfaces while cooling
2. to cool the electrode tips against the parts
3. to hold the parts together while the weld freezes
4. to prevent buckling during nugget expulsion

Answer 2

to hold the parts together while the weld freezes

Question 3

Laser welding is a high energy density process that uses:

1. a constant-current inverter-based power source
2. a concentrated stream of electrons to create heat
3. a focused stream of light to melt the joint edges
4. a tubular electrode without external shielding gas

Answer 3

a focused stream of light to melt the joint edges

Question 4

Friction welding:

1. cannot be used to join dissimilar metals
2. uses a constant-current power source
3. uses a stream of electrons to create a keyhole
4. cannot be used on brittle materials like cast iron

Answer 4

cannot be used on brittle materials like cast iron

Question 5

There are two basic types of stud welding systems:

1. capacitor-discharge and electric arc
2. constant-current and constant-voltage
3. laser beam and electron beam
4. manual and automatic arc control

Answer 5

capacitor-discharge and electric arc

Question 6

How would you increase penetration using the RSW process?

1. increase voltage
2. restrict water flow to electrodes
3. increase clamping pressure
4. extend the dwell time

RSW (Resistance Spot Welding)

Answer 6

extend the dwell time

Question 7

Why is a ceramic ferrule used in Stud Welding?

1. helps contain shielding gasses
2. to protect operator from harm full rays and splatter
3. to protect the liquid weld pool from atmosphere
4. provides containment of heat for better penetration

Answer 7

to protect the liquid weld pool from atmosphere

Question 8

What type of power is used with a capacitor-discharge welding gun?

1. DC+ reversed polarity
2. 400 amps DC
3. AC power
4. High Frequency

Answer 8

AC power

Question 9

Where is Thermite welding used most often?

1. aerospace Industry for welding of thin alloys
2. railway applications
3. for difficult all position welds on nuclear materials
4. for detonation in the making of duplex steels

Answer 9

railway applications

Question 10

What is the transferred arc in PAW used for?

1. plasma spray welding
2. welding and cutting
3. generating heat in non-metals
4. for the quick removal of large fillet welds

Answer 10

welding and cutting