Launchpad, July - August 2005
For a full list of proposed, active and closed projects see here
Two new GSPs (also known as JIPs in the oil and gas sector) have just started at TWI. These are part of the present portfolio of TWI corrosion and materials JIPs valued at about £2.3million (US$4.2million).
Safe specification and operation of plastically strained C-Mn steel pipelines for sour service
Project start: May 2005
Cost per sponsor: two payments of £25,000
Project value: £250,000
Project leader: Thomas Sourmail
The programme will assess the concerns that current hardness limits will not provide assurance that SSC will not occur for plastically strained material eg pipelines and risers laid by reeling, cold field bends etc operating in sour or mild sour service.
The purpose of the work is to demonstrate the effect of plastic strain on sulphide stress cracking resistance in sour and mildly sour conditions for welded pipeline material. It will also determine safe engineering limits in terms of materials, welds, applied strain and environment, hence ensuring freedom from sulphide stress cracking. This will provide improved requirements for weld procedure qualification of pipe laying/reeling operations intended for sour or mild sour service, and improved confidence in the safety of pipelines in such duties.
Sour ECA: Fracture mechanics based weld flaw acceptance criteria for C-Mn steel pipelines in sour service
Project start: June 2005
Cost per sponsor: two payments of £20,000
Project value: £240,000
Project leader: Ruth Hammond
The purpose of the work is to develop an understanding of why conventional engineering critical assessments (ECA) of C-Mn steel pipelines operating in sour service are apparently over conservative. Hence this work will allow definition of an improved approach to materials testing, and assessment of defects in sour service, to permit fracture mechanics-based ECAs to be carried out on ferritic steels operating in sour service.
This will lead to improved reliability of ECAs for sour service permitting improved confidence in the safety of pipelines and cost savings during pipe lay due to avoidance of unnecessary repairs which could account for 2-3% on large projects.
