By joining Group Sponsored R&D Projects TWI Industrial Members gain access to substantial programmes at low cost, with the opportunity to steer work undertaken into areas of specific interest. The following GSPs have been, or are about to be, launched. If you are interested please contact the project leader at TWI.
ERW/HFI welded line pipe for sour service applications
Launched July 98, duration 1 year
Cost per sponsor £6000
Project leader: R Pargeter
Electric resistance welded (ERW)/high frequency induction (HFI) line pipe has been successfully used for many years for a number of high integrity onshore and offshore applications. Its use is being limited, however, due to a lack of confidence arising from historical problems. In particular, there is a reluctance on the part of many operators to use it for sour oil and gas. This is despite the very high quality which is now possible with modern ERW/HFI line pipe, and the potentially very significant savings from its use. This project will aim to address the issues currently preventing the widespread use of such pipe, and will collate experience of the use of modern ERW/HFI line pipe in both sweet and sour environments. The study will cover pipe manufacturers data, experience in fabrication and pipelaying, performance in service, and will also include cost benefit analyses. Depending on the outcome of the study, there will be an option for a focused experimental test programme.
Environmental limits for application of weldments in low carbon martensitic and supermartensitic stainless steels
Launched August 98, duration 2 years
Cost per sponsor £10 000 pa
Project leader: P Woollin
Low carbon weldable martensitic and supermartensitic stainless steels offer lower cost alternatives to duplex stainless grades. However, the limits of applicability of these martensitic materials when welded are not yet defined. The project will examine resistance to corrosion and cracking in a range of recently developed martensitic steels, in both the as-welded and postweld heat treated conditions. Sweet (CO2 - containing) and sour (H2 - containing) environments will be studied, as will the susceptibility to cracking under cathodic protection.
Highly accelerated electronics reliability tests and models for specific environments
Joint TWI/Loughborough University Project
Launched March 98, duration 2 years.
Cost per sponsor £25 000 pa
Project leader: N Sinnadurai
Accelerated ageing methods to prove the reliability of electronics operated in environments other than heat and damp are not supported by adequate evidence or models. TWI proposes a Group Sponsored Project to produce the necessary experimental and field evidence and will apply its expert knowledge of electronics reliability together with the modelling skills of Loughborough University to develop and validate models for specific additional environments. The project will enable sponsor organisations to design reliable electronics products more efficiently and cost effectively.
Friction stir welding of steels
Launched November 98, duration 2 years
Cost per sponsor £15 000 pa
Project leader: P L Threadgill
Friction stir welding has been successfully developed for many non-ferrous alloys, and its feasibility for steels has been demonstrated. The process is fully mechanised, needs no traditional welder skills, no consumables, and produces solid state welds with minimal distortion, and excellent mechanical properties. It is also very useful for joining dissimilar materials. A programme of work is proposed in which aspects such as optimum tool material, tool design, and process parameters will be developed for a number of typical ferritic and stainless steels, in thicknesses up to 10mm, including some grades which are challenging to weld by conventional fusion processes. The project may also address issues such as process economics, joint design, parameters tolerance, reproducibility, mechanical properties, microstructure, etc. The results will allow fabricators and end users to develop further the process for specific applications.
Mechanical and corrosion properties of frictions stir welds in Al alloys
Joint TWI/EWI Project
Launched November 97, duration 2 years
Cost per sponsor £15 000 pa
Project leader: T Dickerson
Friction stir welding (FSW) is now a viable joining process for aluminium structures. However, design data and an understanding of in-service behaviour are needed for its efficient application. The project will generate fracture, fatigue and corrosion design data and a better understanding of failure mechanisms. It will be concerned mainly with butt welds in 6-10mm alloy plate typical of the 2000, 5000, 6000 and/or 7000 series.
Products evolved during hot gas welding of fluoropolymers
Launched March 98, duration 1 year
Cost per sponsor £500
Project Leader M Troughton
The fabrication of structures from fluoropolymers, such as PVDF, ECTFE, PFA, and FEP, is becoming more widespread in the chemical, semi-conductor, paper and pharmaceutical industries. From information provided by the manufacturers, the products generated on decomposition of these materials include hydrogen flouride, hydrofluoric acid, fluoro-olefins, chlorinated hydrocarbons and carbonyl flouride. However, it is not known in what quantities these products are generated during hot gas welding. This project will identify and measure the amounts of products evolved during the hot gas welding of four fluoropolymers: PVDF, ECTFE, PFA and FEP. The results of this work will provide information to allow fabricators to weld fluorpolymers without damaging their health.
Friction stir welding of transport structures
Launched December 98, duration 3 years
Cost per sponsor £15 000 pa
Project leader: Chris Dawes
Friction stir welding (FSW) has proved to be a remarkable process for joining aluminium alloys. With respect to the common butt joint, considerable FSW data is available to enable confident and industrial use. However, the special characteristics of the FSW formation also provide the opportunity for a number of innovation joint designs that could simplify and improve the fabrication of transport structures. The aims of this research programme are to design, develop and prove new joint concepts, which include self locating flexible and paring joints suitable for plates, extrusions and castings. The expected benefits include: weld cost reductions, new design opportunities to improve and simplify the construction of transport structures, improved weld quality assurance, reduced on-site material processing, and a safer welding environment.
Development of Guidelines for reeling of pipelines.
Launched March 98, duration 2 years
Cost per sponsor £20 000 pa
Project leader: H G Pisarski
This project sets out to define realistic flaw acceptance criteria and material property requirements to ensure that steel pipe and girth welds can be reeled and operated with minimum risk of failure. Experimental studies will be conducted on representative pipe materials to measure changes in material properties and assess flaw stability as a result of cyclic plastic strains caused by reeling. This will be complimented by the development of specific analysis procedures for reeled pipe, which will help define acceptance criteria. The project will be carried out in collaboration with DNV.
High velocity oxy-fuel (HVOF) - consistency, economics and spray booth equivalency
Launched November 98
Duration 2 years.
Cost per sponsor £15,000 pa
Project leader: A J Sturgeon
The high velocity oxy-fuel (HVOF) spraying process is increasingly being used to prepare coatings with very low levels of porosity and oxide, and which exhibit performances superior to those achieved with other thermal spraying processes. The ability to achieve the optimum combination of coating properties and process costs is strongly influenced by the availability and cost of both fuel type and powder type. This project will determine the effect that spray booth operators, HVOF systems, fuel and powder types have on process costs, reproducibility and properties such as, deposition rate and efficiency, coating porosity and oxide level for selected coating alloys.
Ceramic and ceramic-metal graded composite for improved protection in high temperature corrosive environments
Launched September 98, duration 2 years
Cost per sponsor £15 000 pa
Project leader: A J Sturgeon
The high velocity oxy-fuel (HVOF) spraying process allows for the deposition of very low porosity, high quality coatings of ceramic and graded ceramic-metal materials. Because of their chemical stability and high hardness these coatings are attractive candidates for the protection, or repair, of components that experience high temperature corrosive environments, often with wear occurring. The aim of this project will be to determine how coating structures can be prepared by HVOF spraying that give optimum protection in realistic corrosive environments, and to measure both corrosion performance and coating costs.
Acceptance criteria for allowable porosity levels in thin gauge aluminium weldments
Joint TWI/Battelle/EWI Project
Launched April 98, duration 2 years.
Cost per sponsor £47 000 pa
Project leader: M F Gittos
The current discontinuity limits, for surface and subsurface porosity and inclusions, applied to thin gauge aluminium weldments in the aerospace industry are very demanding. This means that it is extremely difficult to obtain Class A welds, despite some test evidence that suggests that porosity is not the prime cause of tensile and fatigue failures. This project aims to address this issue by characterising porosity size and distribution in thin gauge 5000 and 6000 series aluminium alloys, modelling the porosity and conducting mechanical testing to development fitness for purpose criteria.
