TWI wins major contract to provide engineering support for production of ITER components

The four-year contract will see TWI (with subcontractors Ceram and The Test House) provide engineering support to F4E on the performance of materials, joining, structural integrity of joints and non-destructive testing activities in support of the manufacture of components such as the vacuum vessel, magnets system, remote handling equipment and in-vessel

parts. The core of ITER is the ‘Tokamak’ based doughnut-shaped vacuum vessel in which plasma is heated and confined in magnetic fields, as no solid material could withstand the extremely high temperature of the plasma necessary for fusion to occur at around 150 million degrees Centigrade.

The construction of ITER, underway at Cadarache southern France, is the next exciting phase of an international fusion development programme to meet the world’s demand for clean and sustainable energy. It builds on the knowledge gathered from various global fusion energy projects including the Joint European Torus (JET) fusion reactor in Oxfordshire UK, where, almost thirty years ago, the first plasma was achieved by fusing light atoms.

TWI has been awarded a major framework contract to support the fabrication of key components of the ITER nuclear fusion reactor, by Fusion for Energy (F4E), the organisation delivering the European contribution to the ground-breaking ITER International Fusion Energy project. ITER is a first-of-a-kind global collaboration. It will be the world’s largest experimental fusion facility and is designed to demonstrate the scientific and technological feasibility of fusion power..

Issue 178 May/June 2012

TWI Events

July 2012

Summer SchoolMintWeldw/b Mon 30Great Abington

September 2012

SeminarJoint TWI/EWI Aerospace eventThu 13 - Fri 14Munich, Germany

Technical Group MeetingMaterialsTue 18Great Abington

October 2012

BSI LaunchBS 7910Wed 24 London

Technical Group MeetingWelding ProcessesThu 25 Yorkshire

SeminarAutomotiveTue 30Great Abington

Exhibitions

Farnborough Air ShowMon 9 - Fri 13 July 2012

Workshops and seminars are recognised Continuous

Professional Development events

T h e m a g a z i n e o f T W I

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continued on p.2Friction stir welding at TWI

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Calling upon all TWI’s technical specialisms and encompassing many metallic and composite materials, the support TWI will provide to F4E will include: engineering and materials studies; assessment and testing of joining technologies including destructive and non-destructive testing; specification of design and manufacturing procedures; failure analysis; technical audits and ensuring appropriate certification, validation and qualification of all procedures and personnel involved in the build of components for the reactor.

TWI Chief Executive Christoph Wiesner commented, ‘TWI has supported fusion projects for over 30 years as

the science has developed from concept into reality. The award of this contract by F4E recognises TWI’s unique expertise and independence in all aspects of materials joining technology, which are critical for the design and fabrication of the reactor components and ultimately to the success of the ITER project. TWI is very proud to play its part in this project which has a vital role in the world’s drive to secure sustainable, low carbon forms of power generation.’

For further information on the project please contact sayee.raghunathan@twi.co.uk

Abu Dhabi Marine Operating Co (ADMA-OPCO)United Arab EmiratesOffshore oil production: platforms and pipelines

Allied Tanks & Fabrications LtdUKSteel tank vessels and steelwork fabrication

Acteon Group LtdUKFoundations and moorings, risers, conductors and flowlines, marine electronics, Instrumentation and surveys

Aleris Aluminium - Rolling Division EuropeBelgiumRolled and extruded aluminum products and aluminium recycling

CSR Zhuzhou Electric Locomotive Co LtdPeople’s Republic of ChinaLocomotive and rolling stock manufacture

Darron SBOUKManufacture of high quality engineering products

INPEX CorporationJapanOil and gas fields, exploration, production and the sale of processed products

Medtronic Vascular Galway LtdRepublic of IrelandDesign and manufacture of medical devices

Nexen Petroleum UK LtdUKUpstream oil and gas

NIPRO CorporationJapanManufacture and sale of medical devices

Overview LtdUKCCTV Design

Pipeline Engineering & Supply Co LtdUKManufacture of offshore pressure vessels and pigging equipment

Scana Steel Björneborg ABSwedenSteel refinery and steelworks

Subsea ComponentsUKProducts and components for subsea applications

Thermaspray (Pty) LtdSouth AfricaEngineered coating solutions

Wind Tower LtdUKWind turbine manufacture

Yanmar Co LtdJapanManufacturing and sales of engines, agricultural machinery

New Members of TWITWI is pleased to welcome the following as Industrial Members

We are always open to applications from Materials Scientists, Metallurgists and Welding Engineers, in particular experts in corrosion and ferritic steels with knowledge of the oil and gas sector.

For current vacancies, please see our careers page www.twi.co.uk/careers or to apply speculatively email your CV and cover letter to recruitment@twi.co.uk

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The concept of the project is aimed at smarter and more energy-efficient manufacturing and the applications that are addressed in the project are categorised in the 'green' alternative energy market.

The super-capacitor battery comprises a bank or stack of batteries, which are interconnected using aluminium (and sometimes copper) tabs. The cumulative aluminium weld area determines the electrical conductivity of the connection, and as such, the performance of the device. Laser welding offers the advantage of high-speed, low heat input and low-distortion compared with more the conventional resistance spot or TIG welding process.

Flexible organic and inorganic solar cells are increasingly becoming important as an alternative source of energy but many challenges remain in the production process of these flexible thin-film solar cells. For instance, an outstanding question is how to interconnect the individual cells? Flexible metal tabs or foils, generally made of aluminium or copper, are welded to the cells to form modules. An accurate, low heat input process is required, since PV cells on <100μm

thick foils are extremely fragile and sensitive to mechanical, chemical and thermal stress. Laser welding offers the advantage of a low chemical, thermal and mechanical impact (due to its temporally and spatially selective energy input) compared with ultrasonic welding and conductive adhesives.

Results achieved up-to-date include:

• A dual wavelength (combined 532nm and 1064nm wavelengths) laser test platform prototype for thin sheet welding and is being tested on thin copper and

aluminium connections• A prototype weld

Monitoring System (WMS) for 1064nm laser wavelengths, has been developed for the in-line quality monitoring of high quality laser welds in thin-gauge aluminium and copper.

• An on-line temporal pulse control system is being developed with respect to the closed-loop control of the laser welding process

• The initial database to contain welding monitoring data has been initiated.

• The initial assessment of eddy current and digital radiography technology to detect small defects (up to sizes of a few tens of nm) in thin-gauge aluminium and copper interconnections has been conducted, using modelling and experimental work.

• Laser welding processing parameters have been investigated at 1064nm and 532 nm wavelengths, for the joining of: aluminium to aluminium, copper to copper and aluminium to copper. Processing parameters investigated include wavelength, spot size, beam quality, pulse length, average and peak power, and repetition rate.

The research leading to these results has received funding from the European Community's Seventh Framework Programme (FP7/2007-2013) under grant agreement n° 260153

QCOALA - quality control of aluminium and copper laser-welded assembliesQCOALA is an innovative new collaborative project funded through the European FP7 programme with the objective of improving the laser welding of highly reflective materials through the development of a fully integrated dual wavelength manufacturing work cell.

Dual wavelength test platform (Courtesy of LASAG)

Spot welding of three copper foils

Reproducible spot welds with a 532nm laser.Thickness 0.1mm at 532nm

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Technology Transfer

Job Knowledge118 A Comparison of ISO 15614 Pt 1 and ASME IX

The question is sometimes asked ‘Can I use our existing welding procedure qualifications?’ where the qualification specification required by the contract is one that has not previously been used by the organisation. This is particularly relevant when substantial costs and/or delays will be incurred if re-qualification of the welding procedures is necessary. The two most frequently encountered specifications are ISO 15614 Pt 1 and ASME IX and whilst these are written with the same purpose (that of giving assurance that a welding procedure will provide the desired joint properties) there are major differences between the two specifications that mean that they are not equivalent. It will not be possible in this short article to cover every welding variable and its range of approval in the two specifications. Where compliance is required then reference MUST be made to the appropriate specification.

With respect to ASME IX the specification requirements can be applied in two ways; ASME intent and ASME stamp. If the welded item is to be ASME stamped this can only be done by a manufacturer who has a quality system accredited by ASME and who holds an appropriate stamp, N stamp for nuclear components, U for unfired pressure vessels, S for power boilers etc. All the requirements of the ASME specifications MUST be complied with, even to the extent of dimensions of the mechanical test pieces and the calibration of testing equipment.

ASME intent is used where the item is not to be code stamped but is perhaps only designed to the relevant ASME code and some flexibility is possible with respect to the manufacturing aspects of specification compliance. Such flexibility may allow the manufacturer to submit to the client or inspecting authority procedure qualification records (PQR) to ISO 15614 Pt 1 for approval that can be shown to be technically equivalent to an ASME PQR.

ASME IX covers the qualification of welders and welding operators, welding procedures, brazing operatives and brazing procedures for the complete range of ferrous and non-ferrous engineering metals (steels, copper, nickel, aluminium, titanium and zirconium alloys) and oxy-gas, arc, power beam, resistance and solid phase welding processes.

ISO 15614 Pt1 covers the welding procedure qualification of arc and gas welds in steel and nickel alloys only. Other alloys and joining processes are covered by additional specifications within the ISO 15614 series.

Both specifications identify essential variable (although ISO 15614 Pt1 does not describe them as such) to each of which is assigned a range of approval. A change to an essential variable outside of its range of approval requires the welding procedure to be re-qualified. ASME IX in addition identifies supplementary and non-essential variables. Supplementary variables are only invoked when toughness requirements are specified by the application code, eg ASME VIII or ASME B31.3. Non-essential variables, as the name suggests, are those variables that are not regarded as affecting the quality or mechanical properties of the welded joint and comprise such variables as the weld preparation, shield gas flow rate, method of back gouging, shield gas nozzle size etc. Although these variables are non-essential it is a requirement that they should be referenced on the welding procedure. It is therefore NOT acceptable to use a butt welding procedure to specify how a fillet weld should be made.

ISO 15614 Pt1 does not identify any variables as non-essential; where a variable is not regarded as significant it is simply not referenced in the specification. There are several variables in both specifications where there is no range of approval; the manufacturer, the welding process

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This article was written by Gene Mathers.

and the application or deletion of post weld heat treatment (PWHT) for example.

In order to reduce the amount of qualification testing, both specifications group alloys of similar characteristics together. Qualifying the welding of one alloy within the group allows the other alloys within the group to be welded. ASME IX assigns the groups numbers with steels being numbered P1 to P15F. Any alloy that does not have a P number is regarded as unassigned; a procedure qualification carried out using an unassigned alloy qualifies only that specific designation of alloy. Until recently only alloys that complied with the ASME and/or ASTM material specifications and/or had a UNS number were assigned P numbers. However, a limited number of EN, Canadian, Chinese and Japanese alloys have now been introduced into the list of assigned alloys.

ISO 15614 Pt. 1 also groups steel and nickel alloys into families with similar properties but is somewhat less prescriptive than the ASME code in that, provided alloys have similar chemical compositions and mechanical properties, the material specification is not relevant – for example a plain carbon steel with less than 0.25%C and a minimum specified yield strength less than 460MPa falls into Group 1 irrespective of whether or not it is a pressure vessel or structural steel or supplied in accordance with EN or ASTM material specifications. To determine into which group the alloy falls reference should be made to ISO/TR 15608, the specification that lists both ferrous and non-ferrous alloys and assigns them a group number.Other significant differences between the two specifications with respect to the arc welding processes are:• ASME IX requires only tensile and bend tests to

qualify a butt weld. ISO 15614 Pt1 requires a far more extensive test programme of visual inspection, radiography or ultrasonic examination, surface crack detection, tensile and bend tests and macro-examination. In certain circumstances Charpy-V impact tests and hardness surveys are also required.

• ASME IX specifies that the tensile strength of the cross joint tensile specimen shall be at least that of the minimum specified for the parent metal and that bend test coupons should have no discontinuity greater than 3mm. ISO 15614 Pt1 has identical requirements for these mechanical tests but in addition specifies an acceptance standard for the non-destructive testing; impact test results, when required, that match the parent material toughness and hardness limits when hardness testing is required.

• ISO 15614 Pt 1 requires Charpy-V impact testing for steels over 12mm thick when the material specification requires it. ASME requires impact testing only when specified in the application standard. This requirement makes heat input a supplementary essential variable in ASME IX but an essential variable in ISO 15614 Pt1.

• Hardness testing is required by ISO 15614 Pt1 for all ferritic steels with a specified minimum yield strength greater than 275MPa. A maximum hardness for joints in either the as-welded of PWHT’d condition is specified. ASME IX does not require hardness testing.

• ASME IX allows a reduction in preheat of 55OC before requalification is required. ISO 15614 Pt1 does not permit any reduction in preheat from that used in the qualification test.

• ASME allows the maximum interpass temperature to be 55OC above that measured in the qualification test. ISO 15614 Pt 1 permits no such increase.

• ASME IX requires pressure containing fillet welds to be qualified by a butt weld procedure qualification test. Non-pressure retaining fillet welds may be qualified by a fillet weld test only. ISO 15614 Pt1 requires a fillet weld to be qualified by a butt weld when mechanical properties ‘.... are relevant to the application...’ ie when it is a load carrying fillet weld. In addition, whilst a butt weld will qualify a fillet weld ‘....fillet weld tests shall be required where this is the predominant form of production welding...’ ie an ISO compliant welding procedure where the majority of the welding is of load carrying fillet welds must reference both a butt weld and a fillet weld procedure qualification.

• Weld metal transfer mode, where relevant, is an essential variable in both ISO 15614 Pt1 and ASME IX but the current type is an essential variable in ISO 15614 Pt1 and a supplementary essential variable in ASME IX.

• A change from manual to automatic welding is an essential variable in ISO 15614 Pt1 but a non-essential variable in ASME IX.

Whilst there are several other variables in the two specifications that have substantially different ranges of approval there are many that have ranges that are very similar – material thickness being but one example. This article has highlighted some of the significant differences but to ensure that the welding procedure and its supporting procedure qualification record are compliant the specifications must be referred to. The answer to the question posed at the start of this article is therefore – it depends upon what you can persuade the client and inspecting authority to accept.

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TWI was recently been asked by a Member company to manufacture several pressure and vacuum vessels. These are used for a variety of purposes, including externally pressurising sealed units for leak testing, high pressure permeation testing with corrosive gases, and vacuum/high pressure impregnation of liquids into permeable substrates.

At TWI we have the specialist expertise in-house to design, manufacture, test, certificate and operate these vessels to our customers’ needs and required specifications. This allows us to operate as a one-stop shop and maintain control over quality and delivery timeframe.

Firstly, the design process requires us to calculate all the parameters for the vessel, not only to ensure that it meets our Member’s needs but most importantly that it meets and exceeds all HSE requirements. This information is given to our highly skilled CAD team to model the required features and produce manufacturing drawings for our precision tool makers. All the materials for the vessels are sourced from specialist companies and after the

components have been manufactured the vessel is welded according to the initial calculations by our certified welding specialists. Once the vessel is complete, all components are checked, seals fitted and it is then ready for testing. The testing, as with all the design and manufacturing processes, is carried out at TWI by our team of experts. The vessel is subjected to an over-pressure hydrostatic test and is held at these pressures to check for leaks. Having passed, the vessel is signed off and certified as fit for use.

To discuss your application and see whether TWI can help, please contact matthew.robson@twi.co.uk

TWI brings together its capabilities in design and manufacturing of pressure and vacuum vessels

TWI is pleased to announce the launch of a new personalised area of its website called MyTWI – a hub for TWI technical knowledge.

MyTWI is tailored to the needs of each user, (Registered, Industrial Member or Professional Member) and allows you to populate your knowledge area by industry preference, giving quick and easy reference to relevant information. Using drag and drop functionality, MyTWI allows you to arrange your page to suit. Simply move topic areas to the location of your choice, or remove (or minimise) those you do not wish to have, then restore them at a later date. Note that when technical knowledge is added to the website, your MyTWI area is automatically updated – with new material appearing at the top of your topic lists.Access MyTWI via www.twi.co.uk/mytwi or by clicking on the orange button at the top-right of our website, next to the login button.

TWI website launches MyTWI – a one-stop-shop for technical knowledge

Q

Aregister now www.twi.co.uk

What is the fracture toughness master curve?

What shear tests exist for adhesive materials?

What is tandem MIG/MAG welding?

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May/June 2012

News in brief

Follow @TWI_Ltd – now going live on TWItter!

TWI is pleased to announce to its Industrial Members, industry contacts and to the public at large that it is now live on TWItter!

Following the TWI page @TWI_Ltd will allow individuals to keep right up to date with hot topics of news and events from the company, to catch exciting developments in materials engineering and joining technologies and see snapshots of knowledge retweeted from relevant industry sectors across the globe.

TWI Chief Executive Christoph

Wiesner comments:

‘I am delighted to announce our launch on TWItter. Aside from the welcome and obvious pun on words, our TWItter presence is a further boost to the success of our online business networking channels, with TWI technical experts at first hand to answer industry queries. Our online presence brings us closer to our customers, and our customers closer to us.’ Why not join us and follow @TWI_Ltd now.

TWI is now on Facebook.

There is now a new Facebook page for TWI where regular news and

updates will be posted alongside a history of the company with photos and stories. ‘Like’ the page and you will be part of this community! www.facebook.com/TwiLtd

TWI is pleased to announce the launch of its YouTube channel.

Our expertise is featured in films on subjects such as friction stir welding, non-destructive testing, plastics joining and long range ultrasonic testing. Go to www.youtube.com/user/twiltd TWI’s YouTube channel, where you can subscribe to keep updated with new films that are added.

For further information on TWI visit the website at www.twi.co.uk

TWI is applying the latest information technology (IT) in its projects, business systems and communications, thanks to its growing team of IT specialists engaged in Continuing Professional Development or holding active membership of BCS, the Chartered Institute for Information Technology. This strengthening in links with the Institute is enabling TWI to optimise existing processes and systems and to apply new thinking, education and knowledge sharing with its staff.

At the start of 2012, 88% of staff working in TWI’s Business Systems and Software Development department registered as individual members of BCS – the start of frequent communications with a number of sections of the IT Institute. TWI’s Business Systems and Software Development group is responsible for company business systems and telecommunications worldwide and for creating engineering software to meet specific industry needs in welding, joining and inspection technologies and customer data.

TWI charters an active approach to IT

Left to right: Lizzy Kavanagh (BCS), Mark Chinery (TWI), Glen Suttie (BCS), Gillian Leech (TWI) and Maurice Whittaker (TWI)

As part of its involvement in the European Research Agency FP7 project framework, TWI is coordinating the MARWIN project. Aimed primarily at Small and Medium Sized Enterprises (SMEs), the project will develop a vision based welding robot with automatic track calculation, welding parameter selection and an embedded quality control system that can reduce manufacturing time and costs, increase production flexibility and efficiency and improve product quality.

Robotic welding is critical to welding automation in many industries. The biggest challenge for small companies is to have a flexible robot that can be set up quickly and switched over to another product line as and when required. Robot reprogramming for small production runs is often necessary and time-consuming, thus expensive for SMEs.

The system will consist of a control computer (1), a welding robot (2) and a vision system (3).

MARWIN will provide a competitive edge for SMEs within the EU. By using the MARWIN system, companies will widen the range of products/services offered, but will also reduce their production costs. The combination of these two elements will result in both higher effectiveness and

significantly increased competitiveness.TWI is acting as project coordinator and is also responsible the development of welding procedures for commonly used materials and joint configurations, and the development of a welding parameter database.

Other project partners include Rolan robotics (Netherlands), Nemetschek (Bulgaria), G-robots (Hungary), Recam Laser (Spain), Sheffield Hallam University (UK) and MFKK (Hungary).

The project began in November 2011 and will run for two years. The system specifications and design are now finalised and work has started on the database creation, the vision system for 3D object reconstruction and the automatic robot trajectory and parameter calculation. More information is available on the project website www.marwin-welding.eu/ or from clement.schuhler@twi.co.uk.

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Connect is the bi-monthly magazine of TWIEditor Penny EdmundsonPhotography Simon Condie Production Penny Edmundson © Copyright TWI Ltd 2012

Articles may be reprinted with permission from TWI. Storage in electronic media is not permitted.

Articles in this publication are for information only. TWI does not accept responsibility for the consequences of actions taken by others after reading this information.

This publication is also available in alternative formats. Please contact marketing@twi.co.uk to request a copy.

Published by TWI Ltd, Granta Park, Great Abington, Cambridge CB21 6AL, UK Tel: +44 (0)1223 899000 E-mail: twi@twi.co.uk www.twi.co.uk

TWI Technology Centre (North East) Tel: +44 (0)1642 216 320 Fax: +44 (0)1642 252 218

TWI Technology Centre (Yorkshire) Tel: +44 (0)114 269 9046 Fax: +44 (0)114 269 9781

TWI NDT Validation Centre (Wales) Tel: +44 (0)1639 873100 Fax: +44 (0)1639 864679

TWI AberdeenTel: + 44(0)1224 691222

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Issue 178 May/June 2012