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TWI assists with critical repair at Canadian nuclear plant

Nuclear expertise, developed by TWI over the last half century, has recently been called upon by a major nuclear operator.

Atomic Energy of Canada Limited (AECL) is collaborating closely with third-party welding experts The Welding Institute (TWI), UK based global specialists in materials joining technology on a highly specialised repair to an aluminium reactor vessel. TWI is helping with the development and testing of welding techniques in what AECL describes as a unique and challenging environment.

The NRU reactor is responsible for producing approximately 30% of the global supply of medical isotopes, used for radiotherapy and other medical treatments. There is virtually no published data on welding of irradiated aluminium, and TWI has been instrumental in advising AECL on development of the specialised repair techniques required for this task.

The first weld build-up inside the NRU reactor vessel was successfully performed on December 12th 2009. The weld repair was conducted remotely by operating the welding equipment from a position of approximately 10 metres above the location of the repair site.

Non-destructive examinations of the weld have found no defects, and preparations are now underway to conduct further repairs.

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Welder Apprentice Scheme in Brunei a great success

Negara Brunei Darussalam is a developing nation located in one of the highest growth regions of the world but it relies significantly on imported manpower and skills.

Back in 2006, Joffren Omar Company Sendirian Berhad (JO) and Syarikat Kejuruteraan Sistematik Sendirian Berhad (SKS) embarked on a plan to train and develop local talent in the welding profession. A new purpose-built facility was built in Seria with technical advice and guidance from TWI who has been associated with JO/SKS since 2000.

A purpose-built facility was constructed to provide training facilities not only for welders but also for welding inspectors, painting inspectors and NDT professionals. The new facilities opened a year ago, in December 2008 and a Senior Supervisor and a Master Welding Instructor were hired with TWI's help.

On 8 December 2009, Joffren Omar Company Sendirian Berhad (JO) headed by Gary Young, presented the first nine 'home-grown' apprentices with a certificate of completion of the Welder Apprentice Scheme. When these young Bruneians signed onto the scheme, they had basic or little knowledge of the standards and competence required to be oil and gas welders. Yet, in a matter of months, through their own dedicated effort and supported by their instructors and supervisors, they have qualified at the highest international standards acceptable to Brunei Shell Petroleum (BSP) and Brunei Liquefied Natural Gas (BLNG), that is, CSWIP level 3 oil and gas, 6G and 6GR positions.

Through this initiative, JO/SKS continue to demonstrate their investment in Brunei's human resources development. Indeed, it is a strong indicator of the companies' commitment to BSP's Local Business Development policy. With the cooperation and support of international organisations such as TWI, and local agencies such as Immigration, Labour, Ministry of Education and others, it is hoped that Brunei will have enough skilled workers to cover its needs in the future.

For more details, please contact: Ibrahim Omar at ibrahimo@josks.com.bn

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CBI Regional director visits TWI in Rotherham

News from RIDO, the Regional Investment and Development Office
Business chief sees the future - in Rotherham
Tuesday January 12 2010

One of Yorkshire and Humber's leading business figures has praised the high-tech activity at the region's Advanced Manufacturing Park, in Rotherham.

The regional director of the Confederation of British Industry, Andrew Palmer, said the Park - the only one of its kind in the UK - was a jewel in the crown not just of South Yorkshire but of the entire region.

"In fact, having seen the wide diversity of companies and nations represented here, it's clear this is an international resource," he said. "We're lucky in our region that we have so many facets to our economy, but this mix of high-quality R&D and hi-tech manufacturing has to be one of the most important."

"This is the future. I've seen it, and it is clearly working for the UK."

He was speaking after visiting several AMP companies, large and small, on a tour organised by Rotherham Investment & Development Office, the Borough Council's regeneration arm.

He took in Dormer Tools UK, Fripp Design and Research, The Welding Institute's TWI Technology Centre (Yorkshire) and the University of Sheffield's Advanced Manufacturing Research Centre with Boeing (AMRC).

Dormer, part of Sweden's Sandvik group, is a world leader in engineering cutting tools. Its premises at the AMP's Evolution development, officially opened in January 2009, incorporate a pioneering training room, a major research and development facility and an international export service to support emerging and developing markets. It employs some 45 people.

General manager John O'Donoghue said: "This is Dormer's key site for sales - in the UK and around the world - with £22m-worth of orders processed. We're also the composite drilling centre for all Sandvik companies worldwide and one of four global training centres, so this is a major operation."

Fripp Design and Research provides 3D computer-aided design, support and rapid prototyping for companies and organisations including Boots, Rolls-Royce and the NHS. It reduces customers' time-scales and costs across a range of operations and products, from highly conceptual packaging to artificial joints and heavily-engineered mass produced components in plastics and metals.

It aims to more than double its workforce on the park in 2010. Managing Director Steve Roberts, who set up Fripp Design and Research with wife Sue and Tom Fripp, said: "Being located on the AMP is of strategic importance to our business as it is the UK centre of excellence for Advanced Manufacturing and associated industries and services - everything from rapid prototyping to rapid manufacture. Our mission is to take 'best practice' in advanced manufacturing from industry and apply this within the health care sector; where we see plenty of opportunity."

TWI is one of the world's foremost independent research and technology organisations, providing industry with engineering solutions in structures incorporating joining and associated technologies. Its welding processes are among the most advanced in the world.

Sector manager Mark Roughsedge, who runs membership development, said: "Since 2002 TWI Yorkshire has helped create and safeguard 1,297 jobs and £81m in turnover for companies in the region, through a series of Yorkshire Forward-funded Technology Transfer Programmes."

The AMRC, which includes the Rolls-Royce Factory of the Future, is one of the world's leading centres of its kind. Two events in December underscored its importance. It played a leading role with Yorkshire Forward, with help from RiDO, in winning the Rolls-Royce Nuclear AMRC for the Park, and providing expertise and composites that helped Boeing's new Dreamliner aircraft take to the air.

It is not only pushing the boundaries in aerospace and other research but is helping produce Britain's next generations of high-quality engineers. Projects director John Baragwanath said that its R&D skills helped companies such as Boeing, Rolls-Royce and Airbus massively reduce their timescales - in one case from 145 hours to 19, in another, from 54 to five. The AMRC aims to double its current 108-strong workforce over the news few years.

Andrew Palmer said: "I've been so impressed not just by the expertise packed into the Park but by the sheer enthusiasm among the businesses. With people and companies like these, the region's future is bright."

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New thermographic inspection training at TWI

TWI is pleased to announce the introduction of its Thermographic Inspection programme, aimed at those responsible for review and approval of thermographic inspection procedures and qualifications.

Infrared thermography is a non-contact technology where accurate temperature distributions across a surface are used to monitor machine or component condition and in some cases to predict failure. This technique is used in many industries especially in manufacturing, distribution, transmission, retail and various processing worldwide. Over recent years the technology has become more affordable to most industries resulting in the need to carry out new technology training.

There are a number of benefits to this training including reducing failures, improvement in safety standards but also a reduction in energy usage.
Also, this technology applies to all engineering disciplines and therefore promotes and enhances multi-discipline working and team building.

Thermography inspection is a diagnostic condition monitoring technique operating at three generic levels each taking five days and include practical testing:

- Level One - Thermographic Inspector, where the main responsibility is to collect accurate qualitative condition information and reporting
- Level Two - Quantitative Inspector, as above and in addition to interpret and analyse results, to develop quantitative thermography and produce written instructions
- Level Three - Management and supervisory, where a thermographic programme is designed and managed or where there is a need to carry out internal training.

In addition to these, TWI will be launching new thermographic inspection specialist options such as:

  • Medical
  • NDT
  • Buildings
  • Electrical
  • Mechanical
  • Research and Development
  • Plant Process

TWI will be introducing a certification scheme later in the year for those involved in condition monitoring or inspection of plant operation and maintenance and equipment.

Anyone with an engineering background is encouraged to attend these new exciting courses.

To find out more and register your interest please contact Customer Services on + 44 (0)1223 899500 or e-mail trainexam@twi.co.uk.

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CO-PATCH - Composite patch repair for marine and civil engineering infrastructure applications

ship

In January 2010 a consortium of 15 SMEs and RTDs from eight European countries have kick started a European (FP7) funded project on Composite Patch Repair for Marine and Civil Engineering Infrastructure Applications - COPATCH.

This is a novel effective repair and/or reinforcement method for large steel structures with defects. Two basic steel structural types will be dealt with in this work, namely marine structures (mainly ships) and steel civil engineering structures (eg bridges). Many of the major problems that these structures face during their operational life are common, with fatigue playing a predominant role among them. Repeated loading is a very common loading condition for both these structures, which, in areas of stress concentrations, leads to the initiation and growth of fatigue cracks. These cracks, if not detected and properly repaired in time, can grow to critical lengths and result in catastrophic structural failures. An additional structural problem of either marine or other large steel structures is corrosion, particularly for vessels and structures designed with thinner plating due to the use of higher-strength steels. Corroded plating or beams jeopardise the strength and stiffness of the structure and measures have to be taken to reinstate the original structural characteristics. Besides the above two major defects of the steel structures, there is often the need for upgrading the strength and/or the stiffness of a structure, enabling it to face new loading conditions or helping in mitigating initial design deficiencies.

Composite patch repairs and/or reinforcements overcome many, if not all disadvantages of the traditional repair methods like welding or use of bolted doubler plates.

  • They do not involve hot works in any way and, therefore, existing deadweight loading or proximity to explosive environments has no particular consequences
  • Patches can be applied directly on corroded steel members by performing a simple surface preparation, thus removing the need for replacement
  • They can be completed faster
  • They exhibit good fatigue resistance
  • They do not cause stress concentrations
  • They result in low added weight

Composite material patching is a very promising method for repairing and/or reinforcing steel structures. Composite patches prevent crack growth and extend the lifetime of the repaired structure. A composite patch works as a crack arrestor by decreasing the stress in the area of the crack tip in the case of cracked structures. A part of the applied load is transferred from the base plate through an adhesive layer to the composite patch, thus reducing the stress levels in the substrate.

Composite patching has proven its effectiveness and cost benefits by its application in the aerospace industry for several years now, since there are already several thousands of operating patches in various aluminium aircraft structural parts. However, there are several fundamental differences between the aerospace applications and bridge/marine/offshore steel applications, which dictate a separate approach and investigation of the problem.

ship

Technical objectives
The main objectives are to demonstrate to all stakeholders that composite patch repairs or reinforcements can be environmentally stable and therefore, that they can be used as permanent repair measures on steel marine structures and steel civil engineering infrastructure applications.

The proposed composite patch repair technology is an innovative and highly competitive product that caters to the needs of marine vessels and civil engineering infrastructures, the latter in the form of steel bridges.

It reduces quite significantly the maintenance costs of many large steel structures, and in the case of metallic bridges it prolongs their design life. The proposed technology creates a new market and it gives the partners the capability of providing high technology and high added value services worldwide, thus improving Europe's competitiveness in specialized and advanced repair works.

The consortium is currently planning to invite interested stakeholders to follow the project activities, within the framework of a relevant stakeholders' forum.

CoPatch Consortium

NATIONAL TECHNICAL UNIVERSITY OF ATHENS

TWI Ltd

BUREAU VERITAS

HELLENIC REGISTER OF SHIPPING S.A.

FRANCISCO CARDAMA S.A.

INSTITUTO DE SOLDADURA E QUALIDADE

METTLE SARL

NORGES TEKNISK - NATURVITENSKAPELIGE UNIVERSITET

UMOE MANDAL AS

ESTALEIROS NAVAIS DE PENISCHE S.A.

THE UNIVERSITY OF SURREY

ASOCIACIÓN DE INVESTIGACIÓN METALÚRGICA DEL NOROESTE (AIMEN)

CETENA S.p.A.

SHIPBUILDERS AND SHIPREPERAIRS ASSOCIATION

ALVEUS d.o.o. (AS2CON)

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Diary dates - Construction and Engineering

'Ship design and operation for environmental sustainability'
Date: 10 -11 March 2010
Location: RINA HQ London, UK

The topic of the next WJS Materials Technical Group Meeting is
'Materials issues in Defence and Security'....
Date: June 2010
Location: TWI, Cambridge

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Where's the join....FSW adopted for invisible stainless repair

Since friction stir welding can be used to join sheet-to-sheet it can surely be adapted for patch repair within sheet material? Yes, but how do you treat the hole created at the exit point?

So goes the traditional thinking on FSW as a patch repair process. However at TWI's Technology Centre (Yorkshire) FSW has been successfully demonstrated as a patch repair technique in 304 stainless steel, without a visible exit point.

The weld completion difficulty has been overcome by traversing the rotating tool up an artificially created ramp a few millimetres above the substrate. This ramp is then machined off once the weld is complete.

The process is expected to be ideal for repairing cracks in vessels or pipes. TWI's application uses a fixed programmable robot, but it is expected that the process will lend itself to being performed in the field.

The positive advantages are that the repair process can be operated in wet environments. The tooling is low force and can be used on portable FSW equipment. The rotating pin exit hole can be eliminated easily, and perhaps most importantly, the repair technique is programmable and repeatable.

To learn more contact Jonathan Martin on jonathan.martin@twi.co.uk

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NEW modelling demonstrations

To explore examples of our core business in the modelling area and to learn more about our work and solutions offered to customers, please follow the link below to our new demonstration pages. Enjoy the animations and presentations which will give you a good overview of how we can help and add value to your company by using the latest modelling technology.

Technology demonstrations

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So, you want to be a ...Responsible Welding Coordinator

Q: How can I become a Responsible Welding Coordinator (RWC)?

A: ISO 14731 states that welding co-ordination is the sole responsibility of the manufacturer and the manufacturer shall appoint at least one responsible welding coordinator.

Responsible Welding Coordinator is a specific job role defined by the manufacturer, and assessment of the fusion welding quality activities against the requirements of ISO 3834-2 or ISO 3834-3 will seek to establish that personnel appointed as welding coordinators are competent to fulfil their allocated responsibilities.

Your competence in fulfilling that role will be assessed on a combination of knowledge, skills and experience that can be demonstrated through evidence of qualifications, certificates and log book or CV, and will be confirmed in interview.

Q: Do I need to be IWE (International Welding Engineer diploma) qualified to be an RWC?

A: There is no actual qualification for RWC, it is a role within a company and during an assessment for accreditation to ISO 3834 the RWC is assessed for their competence to carry out the required role within that particular company; RWC is not a 'portable' title.

The International Institute of Welding (IIW) and European Federation for Welding, Joining and Cutting (EWF) diplomas (I/EWE, I/EWT and I/EWS) have been accepted as satisfying the specific knowledge requirements for Responsible Welding Coordinators.

National qualifications that may be considered to demonstrate knowledge include the Cranfield University MSc in Welding Engineering, and The Welding Institute's professional membership classes of SenMWeldI, IncMWeldI and TechWeldI. Other welding and fabrication qualifications can also be relevant to the assessment.

Remember that knowledge is only one part of the competence assessment and a qualification does not guarantee that you will be considered appropriate for an RWC role. Before committing to any additional training or education, it is important to have your existing qualifications reviewed against the responsibilities you are expected to take on.

Q: I hear that there is a shortage of welding coordinators, so how do I become a consulting RWC and offer my services on a sub-contract basis?

A: The RWC role can be sub-contracted but the responsibility for welding co-ordination remains with the manufacturer. Even though you may be appropriately qualified, you cannot be recognised as an RWC without being assessed as competent against the specific job role that you are expected to fulfil, and this is done during the ISO 3834 assessment of the manufacturer.

Once a manufacturer has nominated you as their RWC, you will be assessed for the role allocated and the sub-contract terms will also be reviewed to ensure that you will have the authority to carry out the assigned tasks.

Q: My employer is seeking certification in accordance with ISO 3834 and expects me to become the RWC, where can I find more information?

A: Please review the information at www.iso3834.org, complete the Preliminary Information Enquiry Form for more guidance and a quotation, and contact the WFCS Scheme Manager if you have any further questions.

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Materials issues surfacing and particulate engineering

WJS Materials Technical Group Meeting held at TWI Conference Centre on Tuesday 2 June 2009

The Welding and Joining Society hosted the anticipated Materials Technical Group Meeting on Tuesday 2 June 2009 at TWI Cambridge Conference Centre and captured both the historical and present issues on the subject of surfacing and particulate engineering, through discussions and presentations from Rolls Royce, Atomising Systems, Hoganas, Leicester University and TWI. The highly successful meeting was co-sponsored by the Particulate Engineering Committee of IOM3.

This one day event included a tour of TWI Surfacing facilities for a demonstration of thermal spraying as well as a visit to the TWI library for a brief introduction to the information services with a particular focus on the latest MI-21 data base (www.mi-21.com, a new service run by TWI in collaboration with NAMTEC and World Metal Index).

Delegates had a chance to network and establish contacts throughout the day. Those, particularly interested in professional development were encouraged to join WJS, The Welding Institute and IOM3, and informed of benefits of professional membership and the registration with the Engineering Council towards for example, CEng status.

For a full summary of this meeting and further information on future meetings of the WJS Materials Technical Group, please contact directly the secretary, Dr. Cem Selcuk at cem.selcuk@twi.co.uk

Left to right: Chairman, Peter Boothby (Macaw Engineering) and speakers: Jeffrey Allen (Rolls Royce), Roger Fairclough (TWI), John Dunkley (Atomising Systems), Paul Nurthen (Hoganas) and Dave Harvey (TWI) with Secretary, Cem Selcuk (TWI)

Full story


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Bespoke solutions, no problem...using advanced phased array

Phased array inspection of bridge structure

The rising popularity of the phased array inspection technique appears to recognise few boundaries. It has recently seen active service in the construction, oil and gas, power generation, aerospace, automotive and even the medical industry for finding very small anomalies

Full case study


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Fatigue Life Prediction for Toe Ground Joints

Weld toe grinding is a well established technique for improving the fatigue performance of welded components. Design codes, such as BS 7608, allow an increase in the fatigue endurance (fatigue life) of 2.2 times after proper weld toe grinding. It is expected that crack initiation would become a more significant component in the total endurance for toe ground joints than for as-welded joints. Although many attempts have been made to predict the fatigue endurance of welded joints by considering crack initiation and propagation, work on ground joints is limited. Furthermore, there is little convincing data in the literature to verify any model predicting the life to crack initiation.

Full report (Members only - login required)

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Welding Co-ordination - The Knowledge to Comply

With the function of welding co-ordination being defined by the tasks and responsibilities set out in EN ISO 14731, and compliance with EN ISO 14731 being required by the quality standard EN ISO 3834 (Quality requirements for fusion welding of metallic materials), and product standards such as EN 15085 (Railway applications - Welding of railway vehicles and components), it is necessary for manufacturers to demonstrate that they have competent welding co-ordinators.

Responsible Welding Co-ordinators must be able to demonstrate technical knowledge at a level relative to the nature and complexity of the products for which they are responsible.

Although the standard does not require the welding co-ordinators to hold any particular qualification or certification, the International Institute of Welding (IIW) has developed a harmonized diploma course, of which the Engineer, Technologist and Specialist levels satisfy the knowledge requirements of ISO 14731 and will assist in the process of company certification. This diploma is available in the UK through TWI Training & Examination Services (www.twitraining.com) and overseas members can find local training by contacting their Authorised National Body (www.iiw-iis.org).

For those who do not hold an IWE, IWT or IWS diploma, there are other routes to demonstrate the knowledge requirements of ISO 14731. Additional training, such as the Welding Supervisors or Welding Inspectors schemes (www.cswip.com), may be relevant to supplementing existing knowledge. Also, the Welding Institute (www.twiprofessional.com) membership grades of Senior Member (SenMWeldI), Incorporated Member (IncMWeldI) and Technician Member (TechWeldI) are associated with Engineering Council registration classes of Chartered Engineer, Incorporated Engineer and Engineering Technician.

These are internationally recognised qualifications that use Professional Review Interviews to assess an individual's knowledge of welding and experience of application. TWI Certification Ltd is able to utilise these qualifications to verify a welding coordinator's knowledge as part of its ISO 3834 assessment process.

Competence comes from the combination of knowledge and experience; don't delay in gaining the qualifications that demonstrate knowledge, as you will also be required to show experience in applying that knowledge to your scope of work.

If you would like some guidance on the possible routes to compliance with EN ISO 14731, please submit the preliminary enquiry form, which can be found with supporting information at www.iso3834.org, enclosing copies of CVs of the candidates that you intend to nominate as Responsible Welding Coordinators. With these details of your intended scope of certification and staff competences, TWI Certification Ltd will identify the options available to you.

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Cost cutting software - predicting distortion and improving fatigue performance

Software which enables non-expert users to predict distortion and achieve better fatigue performance in welded structures is being developed by TWI.

Optweld, as it is known, is a collaborative project, funded by Technology Strategy Board and includes Greenwich and Newcastle Universities, BVT, BAE Systems, the ESI Group, ThyssenKrupp and TWI.

It is designed to appeal to fabricators which use the arc processes to manufacture structures, out of sheet ferrous material, particularly plate thicker than 3mm. End users will include shipbuilders, train makers and land vehicle manufacturers in the military and civil sector.

One of the objectives behind the Optweld project is to promote the use of thinner sheet and sections. It is also expected to reduce the cost of associated computing.

'The main benefit of using this software is to reduce the cost of re-work during the assembly processes' says project co-ordinator Marcus Warwick. 'In other words the need to bash something straight during assembly is avoided, or at least reduced.'

The target user will be a welding engineer assigned to assembling a fabrication from the blueprint stage. The software will recommend an order of assembly, the required process conditions for welding, the weld geometry, the weld speed, the power input, and the thickness and grade of material.

Since the software is largely related to joining thin sheet using the arc processes it is expected to appeal to shipbuilders, train makers and the military and civilian vehicle markets.

The benefits of using the software include improved quality and dimensional accuracy in the finished fabrication. And, by using thinner sheet and section, material costs will be reduced and weight savings achieved.

'The software will allow the user to try different options and find out which gives the least distortion' says Warwick. 'You will be able to input different geometries, different welding conditions, and different welding assembly procedures,... for instance one could compare the relative merits of assembling from one end to the other, as opposed to welding from the middle outwards.'

Above all, manufacturing costs will be reduced in two areas. Fixed costs will be lower in the areas of re-work, fit-up time and scrap. And recurring costs will be reduced through weight savings achieved, improved fatigue performance and reduced repair costs.'

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Training: An Introduction to Friction Stir Welding

The course will be an intensive mixture of classroom lectures, tutorials and practical demonstrations using both video footage and live demonstrations on TWI's equipment. There will be opportunities for individual discussions with TWI engineers.

Among the topics to be discussed will be history of the process, licensing, patents and standards, process fundamentals, process advantages and disadvantages, process control, comparison with other processes, machine technology, tool technology, materials and weld performance issues, quality control, economic benefits, current/planned applications.

Attending the course will give students the necessary knowledge to make balanced decisions about the process and to deal with confidence with suppliers of equipment or friction stir welding process providers/users.

The date for the next FSW training course at Sheffield will be 20-22 October 2009.

More information about the course.

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Specialist Materials and Joining - A new section at TWI?

Well no, not really, more a case of a better description of what two existing sections, Ceramics & Microtechnology, already do.

These two sections have always been closely aligned, having many areas of common interest ranging from packaging for electronics and sensors in safety critical or aggressive environments and thermal management in hybrid vehicles through to development of special purpose coatings.

The two sections have now come together to enhance the service they can offer to Industrial Members across a range of sectors, including rail, marine, off-highway, defence, construction and fabrication.

So whether it's the development of bespoke brazing or diffusion bonding cycles, advice on ceramic materials or precision reliability in safety critical components, SMJ is here to help.

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Correlation of Phased Array Inspection and Fatigue Performance of FSW Joints

Friction stir welding (FSW) of aluminium alloys is now an established joining technique and there is increasing application to joining of critical components and structures. Much emphasis has been placed on optimising tool design and process parameters to ensure joint quality but flaws may still be created in the production environment if the limits of the process window are exceeded. There is a requirement to understand the type of flaws that may be generated, and their causes, when welding conditions deviate from the optimum.

Full report (Members only - login required)

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Laser Surface Hardening with Adaptive Control

Laser surface hardening was one of the first industrial applications of lasers and is rapidly developing as new and more cost-effective lasers, advanced laser optics and control systems, become available. The compact and energy-efficient direct diode lasers give a higher process efficiency and higher energy efficiency, making them more attractive to be integrated into a manufacturing line. The key factor for laser surface hardening is to maintain a constant surface temperature during the process. Variations in the surface temperature can cause fluctuations in the profile of the hardened layer. More recently, the development of new beam-forming optics and process monitoring systems has enabled the process to be controlled in real time to suit different industrial applications. Laser hardening parameters can be adaptively controlled based on the surface temperature of the sample and interactions between the laser beam and workpiece surface to achieve consistent surface properties.

Full report (Members only - login required)

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Non-Vacuum Electron Beam Welding - Progress Report and Future Developments

When the phenomenon of keyhole welding, using an electron beam (EB), was discovered in the 1950s, it was a major step forward for thick section welding. Reduced distortion and elimination of costly joint preparations and even more expensive filler material were of great significance. But as beam powers and penetration levels increased, ambitions to free the process from the confines of a vacuum chamber grew. Sliding seals and local vacuum enclosures were tried with mixed success, mainly because of seal leakage problems. Partial vacuum machines became popular for small components and later Reduced Pressure EB welding minimised the risk of seal leakage. However, the tantalising possibility of projecting high power beams into the atmosphere offers even more advantages.

Full report (Members only - login required)

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Archive



Process monitoring for quality control of friction stir welding

Friction stir welding (FSW) is a relatively new welding technology, which has been rapidly developed and implemented throughout the world, since its invention by TWI in 1991. Control methods for FSW have also developed rapidly during this period, and a number of different systems have been produced by various FSW machine manufacturers and process users. Such systems usually act to control one of the key welding parameters, most commonly z-axis position or force (although systems that control x-axis force, z-axis torque, or weld/tool temperature have also been demonstrated). A review of these different control approaches is timely in order to provide guidelines for process users on the most appropriate choice of system for a given FSW application.

Full report. (Members only- login required)

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Low stress no distortion (LSND) modelling of aluminium alloy welds

Distortion of welded fabrications primarily occurs due to forces produced by differential contraction of different locations as material solidifies and cools from the non-uniform heating produced by welding. Fabrications of thin material are more prone to distortion than thicker fabrications because there is less stiffnesss against out of plane bending moments and lower resistance to buckling. Industry sectors like shipbuilding, automotive and aerospace are particularly affected since their components are fabricated from thin sheets and plates.

Full report. (Members only- login required)

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Welding Estimator Software

Welding Estimator Software

Calculates and compares welding costs for consumables, gases and welding processes. Quick and easy weld, welding procedure and welding project cost estimation tool. To read more...


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Materials Issues in Weld Integrity

The eagerly anticipated WJS Materials Technical Group meeting took place on 27 November 2008 at the Ramsay Moon conference centre situated at the TWI headquarters in Great Abington, near Cambridge.

The highly successful one-day event, supported by the Younger Members Committee of The Welding Institute, helped address Materials Issues in Weld Integrity across several industry sectors including construction & engineering. This conference also allowed useful networking opportunities between participants from industry and academia, with several graduates encouraged on the day for their professional development via membership of The Welding Institute and WJS.

The next Materials Technical Group meeting will be held in spring 2009, details for which will be available via the TWI website.

Watch this space!

For further information and related enquiries, please contact Dr. Cem Selcuk, at cem.selcuk@twi.co.uk

WJS Materials Technical Group Left to right: Secretary, Cem Selcuk (TWI) and speakers: Ian Scott (Joy Mining Machinery), Bob Andrews (BMT Fleet), Isabel Hadley (TWI), Alan Thompson (Corus), Norrie McPherson (BVT Surface Fleet) and John Krancioch (SFR plc) with Chairman, Peter Boothby (Macaw Engineering)

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Successful Seminars on Structural Integrity in Japan and China

In October this year TWI's Structural Integrity Group held technical seminars in Japan and China. Presentation topics included amongst others fatigue, fracture, modelling, distortion, residual stresses and risk based inspection. The Japanese Seminar in Tokyo is a well established annual event which has been successfully running since 1989. The British Embassy was once more a very welcoming and most hospitable partner and many of TWI's longstanding business friends attended the event. The idea to hold a seminar in a similar format in China was a first try this year and we were overwhelmed by the response! About 100 attendees from a large variety of companies were present at the event which was held at the Jiaotong University in Shanghai. The photos below give a little impression of the atmosphere at the seminars. Plans for 2009 are already being developed and we look forward to a long lasting and growing relationship with our Members in Japan and China.

Attendees at TWI Seminar in Japan,
British Embassy, Tokyo		 Attendees at TWI Seminar in China,
Jiaotong University, Shanghai
Attendees at TWI Seminar in Japan Attendees at TWI Seminar in China

For more information, please contact integrityandcorrosion@twi.co.uk

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Critical review of joining processes for powder metallurgy parts

EuroPM2008 International Powder Metallurgy Congress and Exhibition
(29 September - 1 October 2008) Mannheim, Germany

Powder metallurgy (PM) processes have high productivity and are ideal for making near net-shape parts of especially complex geometries from a range of materials, which maximises material utilisation, and hence minimises or eliminates secondary operations such as machining. Secondary operations are common for components made via liquid metal processing, and result in an additional step in manufacturing with substantial cost and waste implications. Despite this obvious advantage of PM processes, however, the joining of materials synthesized from powders has been associated with difficulties related to their inherent characteristics, such as porosity, contamination and inclusions, at levels, which tend to influence the properties of a welded joint.

This paper presents a critical review of the current state-of-art of welding PM components. It also seeks to identify preferred joining processes and identify apparent technology gaps in joining of PM parts, in terms of initial processing and attendant materials issues, with an emphasis on offering solutions to welding problems.

Full paper. (Registered users only- login required)

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Assessment of Bobbin Friction Stir Welding for the Joining of Aluminium Alloys

The friction stir welding (FSW) process was invented by TWI and was originally developed for industrial exploitation via a TWI Group Sponsored Project (GSP), the Sponsors of which were amongst the first to benefit from the new technology. TWI has recently developed a novel enhancement to the FSW process, which offers the potential to produce improved full penetration welding performance using significantly simplified, and therefore cheaper, equipment. The enhanced process can be implemented in two varieties named fixed and floating bobbin FSW. Bobbin friction stir welding has the potential to be a valuable high productivity manufacturing technique for structures of interest to the transport industries, offering high quality, highly repeatable welds at a competitive cost. It is proposed to develop, evaluate, and demonstrate the capabilities and benefits of bobbin FSW via a new GSP. Participants in the GSP will be ideally placed to become early adopters of the new technique and to benefit from the enhanced capabilities that it offers.

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