Pressure vessel fabricator has 4 pressure vessels that were fabricated 2 years ago. U1As signed off and submitted. Customer did not want to take delivery so they never left the fabrication facility. Now the customer wants to lower the MDMT form -20 to -40 which will require the manufacturer to...
Background:
In the ACHE industry SA-214 welded carbon steel (11400 PSI allow. stress at 350 F) is by far the most common material for finned tubes in non-sour applications. If a slightly higher allowable stress is required or if seamless is desired, then seamless SA-179 carbon steel (13400 PSI...
I have SA-516-70N plate that says on the MTR it was charpy impact tested at -30F.
MDMT is -40 F.
Based on my design calculations, charpy impact testing is not required for my MDMT of -40F.
In my opinion, there should be no problem using this plate for -40 F but I'm being told that since the MTR...
