September - October 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
Weld quality and service performance of high power Nd:YAG laser welds in zinc coated steel sheet
To be launched December 2000.
Duration two years
Cost per sponsor £10 000 pa
Existing standards for laser welded steel sheet only give guidelines on the quality levels for weld imperfections, and could well be unnecessarily stringent. This project will aim to investigate weld quality requirements, in particular tolerance to porosity, for laser welded zinc coated steel sheet, so that design and performance targets can be met at lower cost.
Hybrid laser-arc processing for improved productivity and quality
Joint TWI/Institut de Soudure. TWI lead
Launched July 2000
Duration two years
Cost per sponsor £10 000 pa
Project leader: D Howse
Hybrid laser arc welding combines the advantages of both processes resulting in high joint completion rates with increased tolerances to fit up and without compromising joint quality and distortion control. This work aims to develop robust welding procedures which demonstrate the advantages of a range of hybrid laser arc processes. The benefits to industry will include increased productivity, simplified set-up procedures and reduced post weld reworking costs.
Practical application of laser welded double plate panel (LDPP) to ship hull structures
Launched August 2000
Duration two years
Cost per sponsor £18 000 pa
Project leader: M Pereira
Environmental consequences of massive oil spills caused by oil tanker accidents in various parts of the world have raised concern on the capability of these ships to withstand side collision and grounding. The use of double plate panels seems to be the way forward as such structures have a higher impact energy absorption and can improve the crashworthiness of the ship's hull. A potential and economically attractive solution is to use laser welded double plated panel (LDPP) for ship hull side structures and double bottom. This project, therefore, proposes to investigate the design, mechanical properties, welding procedures and the viable application of LDPPs.
Effect of debeading on the long-term performance of butt fusion welds in polyethylene pipes
Launched September 2000
Duration three years
Cost per sponsor £6 000
Project leader: M Troughton
Long-term failure of butt fusion joints in polyethylene pipes has been achieved using a novel whole pipe tensile creep rupture test developed at TWI. Initial results have suggested that the condition of the externally debeaded surface may have led to the initiation of slow crack growth through the weld interface. Based on these results a follow-on project is proposed, to determine the effect of external and internal debeading on the long-term integrity of butt fusion joints in PE pipes and recommend suitable modifications to debeading tools.
Ultrasonic inspection reliability improvement with phased array and other display technology
Launched September 2000
Duration one year
Cost per sponsor £25 000
Project leader: J Rudlin
Operators of industrial plant are under pressure to maintain the availability and safety of plant, while reducing the cost of operation. One common inspection method is manual ultrasonics, but the reliability of this is however suspect in many situations. Recent technical developments in ultrasonic techniques, such as phased arrays, can improve inspection capability but the cost of the new techniques can be up to 10 times that of traditional methods and the improvements have not been quantified. This project will quantify the improvements in inspection gained by the new technology and to provide a methodology for evaluating the cost benefits of their implementation.
Improvement of weld quality and property assessment of thick section steel CO2 laser welds
Joint Institut de Soudure/TWI
Launched May 2000
Duration two years
Cost per sponsor £15 000 pa
Project leader: D Taylor
A recently completed GSP project has demonstrated that CO2 laser welding can produce acceptable quality joints in steel up to 20mm thickness. Laser welding has also been proved to offer significant cost savings in many industries. This follow-on project work aims to increase further these savings through a better understanding of factors which currently limit exploitation of laser welding, particularly those affecting weld quality and properties in thick section steels. Operational envelopes for process parameters and steel composition will be defined. This project will be operated jointly by Institut de Soudure and TWI, with Institut de Soudure acting as the lead organisation. Both Institutes will be actively involved throughout the project.
Acceptance criteria for pipe girth welds inspected using automated ultrasonic testing
Launched September 2000
Duration two years
Cost per sponsor £15 000 pa
Project leader: M Cheatani
Automated ultrasonic testing (AUT) is becoming the method of first choice for inspection of pipeline girth welds, due to its speed, sizing ability and health and safety advantages compared with radiography, and its ability to size the through-thickness dimension of flaws. It is readily integrated into an engineering critical assessment (ECA) approach. The project will address:
- the reliability and accuracy of AUT
- cost effective qualification of inspection by AUT
- flaw acceptance criteria for pipe girth welds inspected using AUT
Laser pipeline welding Nd:YAG (YAGPIPE)
Joint TWI/EWI/Cranfield. TWI/EWI lead
Launched May 2000
Duration two years
Cost per sponsor $30 000 pa
Project leader: G S Booth
Nd:YAG laser technology has now developed to the stage where it offers the capability to make pipeline girth welds at high joint completion rates. The YAGPIPE project will provide process, design and economic information relevant to the field application of Nd:YAG laser pipe welding. A range of material thickness and process options will be considered to enable this potential for cost reduction pipe laying to be realised.
The structural integrity of pipe-in-pipe (PIP) welded joints
To be launched January 2001
Duration two years
Cost per sponsor £20 000 pa
Project leader: R Fletcher
Insulated pipe-in-pipe (PIP) flowlines are increasingly used to transport production fluids from a subsea satellite wellhead back to the processing platform. These flowlines are designed to maintain the fluid temperature above certain process critical values and the welding design of these PIP joints can have a significant effect upon the thermal, mechanical (static and fatigue) performance, onshore prefabrication, and offshore installation efficiency. This project will provide a series of guidance notes which will ensure the critical welding design aspects for PIP joints are fully included at the most appropriate stage in the design, manufacturing and installation programmes.
