I have a CWI test questions that I am having trouble understanding. It goes as follows.
What are the minimum preheat and interpass temperatures for welding 1/2 inch thick ASTM A709 Grade 36 Steel with an E6013 electrode when the base metal temperature is less than 32 F.?
a) 0 preheat 32 interpass
b) 32 preheat, 32 interpass
c) 50 preheat, 50 interpass
d) 70 preheat, 32 interpass
e) 70 preheat, 70 interpass
(All temps in F)
My solution: D per page 57 D1.1 pg 57. Note a requires 70 for preheat, but maintaining interpass temp.
Key Solution: E
This is confusing. Does the interpass temperature now change to 70 due to the below 32 temp before the preheat? I was under the impression that the interpass temps would be okay above 32 after the original preheat to 70.
Thoughts?