January - February 2001
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
Practical application of laser welded double plate panel (LDPP) to ship hull structures
Launched October 2000.
Duration three years
Cost per sponsor £32 000/£45 000
Project leader: M Pereira
Environmental consequences from massive oil spills caused by oil tanker accidents in various parts of the world have raised concern about 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 hull. A potential and economically attractive solution is to use laser welded double plate panel (LDPP) for ship hull structures and double bottom. This project, therefore, proposes to investigate the design, mechanical properties, welding procedures, viable application of LDPPs, etc.
Safe fabrication of vanadium modified low alloy steels for petrochemical applications
To be launched March 2001
Duration two years
Cost per sponsor £15 000 pa
Project leader: A M Barnes
The vanadium modified low alloy steels eg 2.25Cr1MoV and 3Cr1MoVTiB offer favourable elevated temperature properties, particularly in relation to hot, high pressure, hydrogen attack, and high temperature strength. However, in a number of recent fabrication projects, involving thick section, highly restrained joints, brittle fracture problems during fabrication have been encountered. These have raised questions concerning the mechanical properties of the parent steels and weld metals prior to the final postweld heat treatment. The objectives of the project are to assess the effect of interpass temperature, intermediate heat treatment and weld metal composition on the as-welded toughness to seek improvement aimed at avoiding these costly delays due to brittle fracture. The programme will also determine whether these alloys require different dehydrogenation treatments to normal, non-V modified grades.
Weld quality and service performance of thin sheet aluminium laser welds
To be launched March 2001
Duration two years
Cost per sponsor £12 500 pa
Project leader: G Verhaeghe
Present aluminium laser welding standards quote acceptance levels for imperfections that are not necessarily related to the fitness-for-purpose of the end product. The application of such standards may be needlessly stringent, causing unnecessary costs. The object of this project is to determine the factors affecting porosity formation and to develop fitness-for-purpose based acceptance criteria for allowable porosity in thin gauge aluminium laser welds. Typical joint configurations will include sheet-to-sheet butt joints, as used for tailored blanks, and sheet-to-extrusion lap seam and lap fillet joints, as used for pillar to roof joints. Benefits will include an improved understanding of the influence of joint preparation and cleaning method on the level of porosity in thin gauge aluminium laser welds, together with cost reductions through the establishment of rational criteria for flaw acceptance in such laser welds.
Acceptance criteria of thin steel sheet laser welds
To be launched March 2001
Duration two years
Cost per sponsor £10 000
Project leader: A Woloszyn
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.
