Question

preheating is always required for pipe welding?
true
false
question 20
4 pts
open groove pipe root passes should not be welded using ac polarity?
true
false

Explanation:

First Question (Preheating is always required for pipe welding?)

Preheating in pipe welding depends on factors like material type (e.g., some thin - walled or low - carbon steel pipes may not need preheating in certain conditions), pipe thickness, and ambient temperature. It's not always required. So the correct answer is False.

For open groove pipe root passes, DC (Direct Current) is often preferred over AC (Alternating Current) because DC provides better arc stability, penetration, and control, which are crucial for root passes. AC polarity is not suitable for open groove pipe root passes in most cases, so the statement is True.

Answer:

False

Second Question (Open groove pipe root passes should not be welded using AC polarity?)