Not logged inAmerican Welding Society Forum
Forum AWS Website Help Search Login
Up Topic Welding Industry / Inspection & Qualification / Wrong material use
- - By Richman (**) Date 11-26-2009 10:09

All materials to be use in propane refrigerant line or "PR" line in our LNG project is Low temperature carbon steel(LTCS). During our line checking we found 1 flange use by our sub-contractor is 300# carbon steel(A105) instead of A350-LF2(LTCS). We know the fact these materials can withstand the same pressure during hydrotesting since it's the same rating, what about if we miss this kind of materials during inspections what was the effect or causes of this materials during pre-commissioning, start-up and operation of the Plant?
Parent - - By MBSims (****) Date 11-26-2009 15:22
Brittle fracture and rupture of the line.
Parent - By CWI555 (*****) Date 11-27-2009 11:10
Brilliantly simple and to the point.
Parent - By G.S.Crisi (****) Date 11-26-2009 21:15
Just to broaden the perfect MBSims' reply.
At room temperature (i.e., above freezing point), both metals behave the same, because both are carbon steel, and both will pass the hydro test.
At low temperatures, however (i.e., below freezing point), plain carbon steel like A 105 is prone to brittle fracture and that's why you should use LTCS.
Giovanni S. Crisi
Sao Paulo - Brazil
Parent - - By Nanjing Date 11-27-2009 14:45
How thick is it and what is your design specification, any PWHT? From an engineering perspective you could justify going down to 6mm wt. with the omission of impact tests.
Parent - - By G.S.Crisi (****) Date 11-27-2009 18:44
Nanjing,
Richman is talking about a series 300 pounds, A 105 forged carbon steel flange, but he doesn't states the diameter.
Giovanni S. Crisi
Parent - By Richman (**) Date 11-28-2009 12:43 Edited 11-29-2009 04:08
sorry I forgot to inform, diameter is 2"
Up Topic Welding Industry / Inspection & Qualification / Wrong material use

Powered by mwForum 2.29.2 © 1999-2013 Markus Wichitill