Lecture 6 Flashcards
What is the temperature reached by burning oxyacetylene?
Approximately 3250C
What are the three types of flames obtained with different oxygen-acetylene ratios?
- Neutral flame
- Oxidizing flame (hotter, harmful to steel)
- Carburizing flame (for steels)
What is a kerf?
The gap created when oxyfuel-gas cutting.
What are the two types of arc welding?
DCEP and DCEN
What is a characteristic of DCEP arc welding?
It has an oxide cleaning property.
Modes of metal heat transfer, from lowest to highest current.
Short circuit, globular, spray.
Can spray transfer be used in all welding positions?
Yes
What is the “coldest” mode of heat transfer?
Pulsed spray transfer (low current creates blob, high current explodes blob).
What are the two main characteristics of consumable electrode arc welding?
Medium rate of input, depth of fusion zone equal to its width.
What is the advantage of flux-core arc welding compared to shielded metal arc welding?
The electrode can be continuously fed through a gun.
What shielding gas produces the hottest arc/deepest penetration in GMAW (MIG)?
Helium, followed by argon and then CO2.
Argon requires a XXX flow rate since it is XXX than air.
Low, heavier
Helium requires a XXX flow rate since it is XXX than air.
High, lighter
What are the two main methods of non-consumable electrode arc welding?
GTAW (TIG) and plasma arc welding.
What gas produces the most stable arc for TIG?
Argon
Why is helium used for overhead welding?
Because it is lighter than air.
How can you increase the deposition rate for TIG?
Preheat the filler rod.
What are the two types of plasma arc welding?
Transferred (electrode-workpiece, 33,000C) and non-transferred arc (electrode-welding gun, 16,500C). Also dual arc.
