March - April 2000
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 GSP's have been, or are about to be, launched.
For a full list of proposed, active and closed projects see here
Friction stir welding of steels
Started March 2000
Duration three years
Cost per sponsor £16 000 pa
Project leader: R Johnson
Sponsors: Boeing, MTS Systems, ESAB, GKSS
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 thick, 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 the process further for specific applications.
Friction stir welding of transport structures
Started January 1999
Duration three years
Cost per sponsor £16 000 pa
Project leader: Chris Dawes
Sponsors: Boeing, BAe, British Al, CSM, DERA, ESAB, FBM Marine, General Trailers, Hydro Aluminium, Materialteknik, MTS Systems, Raufoss, SAPA
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 are self locating, flexible and/or accommodate fit-up variation. Such joints will be designed to be 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.
Cost effective operation of production equipment in sour service
Launched October 1999
Duration two years
Cost per sponsors £15 000
Project leader: R J Pargeter
In oil and gas production, service may change from sweet to mildly sour conditions. Significant cost savings may accrue from the continued use of components designated for sweet service rather than changing to those for sour conditions, provided they can be demonstrated to retain safe, acceptable performance in mildly sour environments. With regard to ancillary equipment such as pumps and valves, a knowledge of the synergic relationship between stress, material and environment upon the potential for stress corrosion cracking, may allow continued use of these components in a wider range of environments than presently permitted. Similarly, specification of such equipment for new production facilities may offer significant reduction in the capital expenditure. This project will extend the database previously generated at TWI on welded C-Mn and low alloy steels, to cover a wider number of materials, at a range of applied stresses, thereby providing data to support these engineering decisions.
ERW/HFI welded line pipe for sour service applications
Launched March 1999
Duration one year
Cost per sponsor £6 000
Project leader: R J Pargeter
Sponsors: Arabian Pipe Company, BP Exploration, British Steel plc, Chevron Research & Technology Co, Corinth Pipeworks SA, Engineers India Ltd, Niobium Products Company GmbH, POSCO, Saudi Arabian Oil Company, Saudi Steel Pipe Company Ltd, Shell UK Ltd, Stelco Inc
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.
Cathodic protection of duplex and super duplex stainless steel
Started August 1998
Duration two years
Cost per sponsor £5 000 or £20 000 pa
Project leader: P Woollin
Sponsors: Arco, BP, DERA, HSE, Marathon, Shell, Weir, Chevron, Fabrique de Fer
Ferritic-austenitic stainless steels play a major role in the offshore oil and gas industry. However, failures have been experienced of subsea components as a result of hydrogen pickup from cathodic polarisation. The project aims to define the effects of material, environmental and loading variables on the risk of cracking, so that the problem can be avoided in present and future installations.
Development of an industrialised process for joining magnesium to aluminium steel for light-weight automotive components
Launched April 2000
Duration two years
Cost per sponsor £12 500 pa (£9 500 buy back fee)
Project leader: L S Smith
A previous Group Sponsored Project (GSP) has demonstrated elevated temperature mechanical fastening techniques can be used to complete high integrity joints between magnesium alloy die-castings and aluminium alloy or steel sheet. This project will design and build a prototype self piercing riveting machine for the rapid production of such joints and will establish the mechanical and corrosion performance of joints made using the industrialised machine. The project will therefore deliver a cost effective and high productivity method of joining magnesium alloy components to dissimilar sheet materials (eliminating many of the problems associated with bolts) and give increased flexibility in the integration of magnesium alloys into modern vehicles, thus easing the transition of lighter-weight components.
Evaluation of the delay time before inspection for detection of hydrogen cracks - Phase IV
Start March 2000
Duration one year
Cost per sponsor £14 250
(buy back £10 000)
Project leader: R J Pargeter
Costly delays (typically 48-72 hours) after welding steel structures are imposed to ensure that any hydrogen cracking occurs before inspection. Previous projects at TWI have allowed substantial reduction in this time and this project will extend this work to provide further data on flux cored arc welds and fillet welds. The ability to use shorter delay times will substantially cut fabrication costs (for a large shop fabrication savings would be ~£750 per day, but would be significantly more for offshore work).
Interfacing NDT with engineering critical assessments Ð NDT performance and reliability
Start April 2000
Duration two years
Cost per sponsor £12 000 pa
Project leader: B Kenzie
The widespread use of engineering critical assessment (ECA) to determine the fitness for service of components or structures containing flaws, places a requirement of non-destructive testing (NDT) to provide flaw size data of appropriate accuracy. The project will investigate the 'Measured Response versus Actual Flaw Size (â versus a)' method for quantifying the performance and reliability of NDT, by evaluating real data obtained from a large TWI database of flaw responses. The approach will include determination of appropriate distributions and uncertainties for flaw measurements made by different NDT techniques, and will also examine the implications for the perceived probability of failure of undetected or unreported flaws.
Study of risk-based life management practices and their relationship to fitness-for-service assessment methods
Launched December 1999
Duration one year
Cost per sponsor £10 000
Project leader: G Xu
Pressures on process and power plant operators to increase competitiveness whilst maintaining regulatory compliance is fuelling an upsurge in the application of risk management approaches to optimising plant assets. Risk-based inspection (RBI), risk-based maintenance (RBM) and fitness-for-service (FFS) assessments are key products within this area. These can, and do assist operators in minimising plant downtime and risk of loss or in maintaining plant availability at reduced maintenance costs. The objective of the project is: (a) to review the strengths and weaknesses of the RBI/RBM/FFS methods from technical and sector application viewpoints; (b) to collate user experience feedback on the currently available RBI/ RBM/FFS products. It is anticipated that the project will deliver application oriented guidelines specific to the various sectors.
Products evolved during hot gas welding of fluoropolymers
Launched October 1999
Duration one year
Cost per sponsor £500
Project leader: M Troughton
Sponsors: Health & Safety Executive
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 fluoride, hydrofluoric acid, fluoro-olefins, chlorinated hydrocarbons and carbonyl fluoride. 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.
Reliability of single-sided girth weld inspection
Joint TWI/UCL Project
Started April 1999
Duration two years
Cost per sponsor £17 500 pa
Project leader: J Rudlin
Sponsors: BP, HSE, Marathon, Coflexip, Stena Offshore, Statoil, Dril-Quip
This project will underpin the safe and cost-effective use of single sided girth welds, by quantifying the reliability of inspections of the weld root from the outer surface. It will determine the reliability of both manual and state-of-the-art techniques, and their implications on fatigue design of the joint. It will also establish a unique specimen library that participants can reuse, in the future, to qualify and further develop their inspection techniques. The project will focus on the types of weld used for risers, but will have generic application.
Metal ceramic graded composite coatings by HVOF spraying for improved protection in corrosive environments
Launched October 1999
Duration two years
Cost per sponsor £15 000 pa
Project leader: R Halldearn
Sponsors: Ministry of Defence, Rolls-Royce plc
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.
Copyright 2000, TWI Ltd
