Launchpad, July - August 2004
For a full list of proposed, active and closed projects see here
Development of automated ultrasonic inspection capability for internally clad steel risers
Launch date: July 2004
Cost per sponsor: £25 000 pa, two payments
Project Leader: John Rudlin
Deep-water risers have a requirement for high reliability of inspection during fabrication in order to withstand fatigue loading and minimum inspection in service. Automated ultrasonic testing (AUT) using zonal discrimination has now become the standard method for C-Mn steel riser inspection. For sour service, the preferred industry technique is to have an internal cladding on a C-Mn steel. For this pipe, there is a particular issue regarding transmission of ultrasound in the clad material, which will be seriously affected if the acoustic velocities in the cladding and the pipe material are different. The weld material (of similar material to the cladding) could also be difficult to inspect.
In this project, TWI will investigate and develop optimised inspection procedures for the clad pipe welds by use of experimental techniques and modelling.
Safe specification and operation of plastically strained C-Mn steel pipelines for sour service
Launch date: June 2004
Cost per sponsor: £25 000 pa, two payments
Project Leader: Paul Shenton
Plastic straining occurs in pipelines during, for example, pipe reeling and laying operations, other installation operations and during service (buckling, upheaval). Such straining can affect materials properties such as hardness, but it is commonly assumed that if traditional safe hardness levels are maintained after straining, there will be sufficient control over the risk of sulphide stress cracking (SSC) in service. Recent work carried out at TWI, however, has demonstrated that hardness levels less than 250HV are not always safe for plastically strained material and work is therefore proposed to develop understanding of the effect of strain on SSC, in terms of prestrain and hardness, and to determine engineering limits to ensure safe operation.
Underwater in-situ repair for FPSO and semi-submersible oil rigs
Launch date: July 2004
Cost per sponsor: £30 000 pa, two payments
Project Leader: Afshin Motarjemi
If repairs to an FPSO or semi-submersible oil rig are required, they must be done while the vessel is on station to avoid the unacceptable costs of removal of the vessel from service. Safety and ballast considerations dictate that such repair must be carried out underwater. In order to demonstrate that adequate weld integrity can be achieved and to qualify new wet underwater welding procedures, a programme of simulated repair welding is proposed in this project outline. The resulting test welds will be evaluated by ultrasonic testing and subjected to conventional qualification testing. The programme of work also includes cross-weld fatigue testing, the results of which will be the basis for obtaining approval for the underwater hull weld repair techniques from Classification Societies.
Validation of CIVA ultrasonic testing (UT) modelling software
Launch date: July 2004
Cost per sponsor: £12 500 pa, two payments
Project Leader: Davide Kleiner
CIVA modelling software developed by CEA (France) is being used worldwide by an ever-increasing number of companies. The complete software comprises ultrasonic testing (UT), Eddy current and radiography modelling modules. TWI proposes to launch a Group Sponsored Project to validate the UT modelling code for applications specified by the sponsors. This project will benefit organisations which are planning to, or already use CIVA, but are inhibited by the large initial investment of time and money required for validation.
