Optimising design and performance of engineering components

Abstract

Introduction

The 21st Annual Conference of the Sheffield Metallurgical and Engineering Association was held on the 19 and 20 June 2012 at the Endcliffe Conference Centre, University of Sheffield. The conference addressed the design, material requirements and manufacturing processes suited to specific types of alloy component. Five sessions explored the requirements with respect to strength, size and weight of component plus the role of surface engineering and enabling and emerging technologies.

Dr Stephen Court, Operations Director, Nuclear Advanced Manufacturing Research Centre set the scene with his opening address ‘Manufacturing challenges in the nuclear power industry’. In his closing address Mick Steeper, Siemens Metals Technologies explored the Vision, Achievement and Legacy of IMMPETUS, Institute for Microstructural and Process Engineering at the University of Sheffield:

Opening address

Dr Stephen Court, Operations Director, Nuclear Advanced Manufacturing Research Centre reviewed the Manufacturing challenges in the nuclear power industry. He explained that there are now approximately 440 commercial nuclear power reactors operating in 30 countries, with 377 GWe of total capacity and more than 250 reactors planned over next 25–30 years representing a £1·7 trillion market. It is recognised that new nuclear power stations will have an essential role in delivering future UK energy over the next 15–20 years. The UK is scheduled to build between 10 and 13 new nuclear power stations, representing the deployment of up to 16 GWe of installed capacity, with an anticipated investment of £60 billion (Fig. 1).

Figure 1.

Planned and proposed reactors (January 2012)

Given that the UK has not built a new nuclear power station since the pressurised water reactor at Sizewell B (1987–1994), the UK based nuclear manufacturing supply chain faces a number of challenges, which must be addressed if UK companies are to realise a significant share of the UK’s new build programme and also the global market.

Mechanical components such as pumps, valves, seals, heat exchangers, tanks and vessels need to be machined, welded and inspected/tested using processes which are cost competitive, energy efficient, and guarantee the high quality and reliability required for 60+ years of service in a new nuclear power station.

Nuclear Steam Supply System was highlighted for Areva EPR and Westinghouse AP100. There are opportunities for the introduction of new manufacturing technologies, with reference to the processes of:

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advanced machining

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welding and cladding

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inspection and non-destructive evaluation (NDE)

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near net shape manufacture

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automation/mechanisation

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modelling, simulation and visualisation.

The Nuclear AMRC was established in December 2009 and provides a focal point for the UK civil nuclear manufacturing industry.

In the future there will be further challenges and opportunities resulting from the development of the many different small, modular sized nuclear technologies which are currently being considered (Fig. 2).

Figure 2.

Small modular reactors. Many different small, modular sized nuclear technologies (SMRs) being discussed for commercialization. Based on Pressurised Water reactor (PWR), High Temperature Reactor (HTR) and Fast Neutron Reactor (FNR) technologies

Strong components

Dr Paul Davies, Sector Development Manager – Defence Products, Tata Steel gave a presentation on Perforated ultra high hardness steel for applique super high strength armour plate. The armour is perforated to deflect projectiles and hence more effectively dissipate their energy. The concept, involving isothermal transformation to a bainitic microstructure rather than quenching and tempering, allows the development of very high strengths and the microstructures have been found to have excellent ballistic properties. Furthermore, the steel can be formed and drilled in the hot rolled condition prior to final heat treatment. The development of the product from the initial alloy design, through property optimisation, identification of a viable supply chain, to commercial production was described (Fig. 3). The work provides a good example of cooperation between academia, material producer and end user to develop a commercial product from a novel metallurgical concept.

Figure 3.

Background history: super bainite

Mrs Jackie Butterfield, EMEA Technical Support Manager, Bridon International Ltd, gave a presentation on Technical challenges in the development of ropes for deep sea applications. The presentation looked at rope design and manufacture and then at market drivers, particularly in the offshore oil and gas sectors. Future exploration activity will involve working in deeper water, over a wider temperature range and in more acidic environments. This requires ropes with enhanced properties such as strength, flexibility, fatigue and abrasion resistance. At greater depths strength/weight ratio becomes increasingly important. As an example of products developed to meet these needs the Bristar concept (Fig. 4), was described in which a polymer insert is placed between the strands in the rope giving improved crush resistance and reducing contact between the strands. The latter leads to less internal friction and improved fatigue resistance. The presentation clearly outlined the increasing demands being places on wire ropes by the end user and the response of the manufacturer in terms of process and product development.

Figure 4.

Dyform Bristar concept with polymer insert

Dr Lee Shaw, Group Technical Director, Firth Rixson Ltd talked on the subject of Developments in controlling the properties of critical components. The company supplies components to demanding sectors including aerospace, power generation, medical and petrochemical. Properties such as strength, ductility, toughness, microstructure, grain flow, dimensional stability and residual stresses must all be closely controlled (Fig. 5). Examples were given of how this is achieved through the various manufacturing stages. Remelting by both ESR and VAR were discussed and examples of the use of finite element modelling of forging processes were presented. Finally likely future developments were anticipated. These include tightening of control variables in manufacturing processes, increased automation and finally the introduction of new processes such as isothermal forging to give improved control and reduced costs.

Figure 5.

Typical Extruded Parts

The final paper in this section was on Development and application of high strength rails and was a joint presentation by Howard Smith from Tata Steel RD&T and Ross Walker from Tata Steel Rail Technologies. The paper described the increasing demands being placed on track products, in particular with respect to wear and rolling contact fatigue resistance. Two recent product developments were described. The first, HP rail, involves metallurgical engineering of the existing pearlitic microstructure to improve performance. This was achieved by: increasing the carbon level to raise the cementite content of the pearlite; raising the silicon level to give solid solution strengthening and alloying with vanadium to give precipitation strengthening. The resulting product gives significant improvements in wear rates and rolling contact fatigue performance (Fig. 6). The second development, 330 V, is a premium grade for embedded tram track. For this application rail life is especially important as excavation and replacement of embedded rail is extremely costly and disruptive to traffic in urban locations. Similar metallurgical approaches have been used to enhance properties and despite the higher carbon content this has been achieved without reducing weldability. The presentations were an excellent examples of how sound metallurgical principles can be used to incrementally improve performance even in well established products such as rail.

Figure 6.

Rolling contact fatigue test results

Large components and structures

Dr Andrew Levers, Industrial Performance Manager of Airbus Operations Ltd, gave a presentation entitled A review of wing skin forming processes – A380 as big as it gets. One of the major problems in forming the wing skins for the A380 is their size, up to 35 m long by 3 m wide. The top and bottom skins require separate sets of properties (Fig. 7), and are made using different forming processes and aluminium alloys. For the bottom skin aged Al–Cu 2XXX series alloys are used because they exhibit good static strength and damage tolerance. They are formed by shot peen forming which involves bombarding the material with spherical shot to induce local plasticity. It has the advantage that specific tooling is not required for different components.

Figure 7.

Wing skin design criteria

For the upper skin higher hardness and tensile strength are required and precipitation hardened Al–Zn 7XXX series alloys are used. The high hardness and complex shape mean that creep age forming is used. This takes advantage of the stress relaxation which occurs during precipitation hardening treatments and the material is formed on to a tool using a pressure differential. The talk was a fascinating description of the use of complex forming processes to produce very large, safety critical components.

The next talk was on the topic of Developments in steel use for offshore wind and was given by Joe Lee, Principal Metallurgist at Siemens Metals Technologies. The potential market for steel in offshore wind over the next 20 years is about 30 million tonnes. In the future the larger offshore units will pose significant challenges to the current UK supply chain. Monopiles are a viable solution for wind towers in shallower depths, but in the future towers in the North Sea will be set on bedrock at depths of 80 m. Solutions such as tri-pile structures offer increased stability (Fig. 8), but there is real threat of substitution for steel in these applications. A further problem is that the UK plate mills cannot supply material of a sufficient width, whilst overseas plate mills can meet these demands. The UK is in the right location and has previous offshore experience from North Sea Oil, but significant investment will be required if the supply chain is to be able to meet the demands for future deep water, offshore wind towers.

Figure 8.

Tri-pile construction for offshore wind towers

Mark Tomlinson, Operations Director, Sheffield Forgemasters Ltd, gave a talk entitled Methods without madness – a design led approach to large product realisation. Sheffield Forgemasters has a unique ability to design and manufacture large forgings, castings and fabrications using their fully integrated process route from melting to final dispatch. The product design and choice of processing route are closely interlinked and this was illustrated through a series of case studies. The topics covered included the offshore market. First, the replacement of welded constructions by cast nodes to produce a stronger, more easily assembled and inherently more reliable product was described (Fig. 9). Second, the replacement of large castings by forged equivalents, involving modelling work which delivered a lower cost steel product. The expertise of Sheffield Forgematers is not only used for internal product and process route optimisation. It can also be used to optimise the manufacturing operations within the whole supply chain. This was illustrated for the manufacture of components for use in wind towers. The talk showed how a flexible approach to manufacture allowed the process route to be tailored to customer needs including product integrity, cost, ease of manufacture and final assembly.

Figure 9.

Cast node

The final talk in this session was given by Jeremy Mansfield, Senior Engineer, Doosan Power Systems, on the topic of Current status of post-combustion CO₂ capture (PCC) materials technology for fossil fuel plant. Of the available technologies for CO₂ capture PCC is considered to be closest to commercialisation and the most suitable for retrofit to existing plant. The operating costs are largely a function of corrosion/degradation of materials, fouling of material surfaces necessitating more regular cleaning, and contamination of the process fluid. Cost reduction is a major driver and traditional PCC materials such as austenitic stainless steels are considered too expensive. The use of a range of materials was considered and lean alloy duplex stainless steels appear attractive because of their lower alloy content, reasonable pitting resistance, weldability and ease of machining. A summary of Doosan Power Carbon Capture Projects is shown in Fig. 10. Large demonstration plants are planned for 2012–2016 with full commercialisation around 2017.

Figure 10.

Doosan power systems post-combustion capture projects

Light components

Colin Harper, Principal Engineer, Swinden Technology Centre, Tata Steel RD&T described An optimised solar frame support system. In 2011 the Construction Technology Group developed a new long spanning, steel solar panel support frame in conjunction with Tata Steel Construction Products to provide a highly competitive solution for this growing market in the energy sector.

He outlined the evolution of frames and beams from an original system through to ‘E-rail’ frame systems that enable sliding solar panels to be supported. The new solution allows greater spans than previous systems and a cost effective solution (i.e. easier and quicker to build). A unique product was developed for Tata Steel by designing a new rail and frame to remove the need for supplementary components. Interestingly, the weight of expensive solar panels was replicated by plywood panels and sand bags (Fig. 11).

Figure 11.

Solar panel support frames tested by loading plywood panels with sand bags

Superplastic forming of titanium components was presented by Bill Swale, Technical Executive of RTI Advanced Forming UK (formerly Aeromet International). The company has 30 years experience in forming titanium sheet and it has 17 superplastic and hot forming presses, as well as post processing chemical milling and laser cutting facilities.

Titanium, which has a stable two-phase microstructure during forming, exhibits high ductility under slow strain rates and high temperatures (∼900°C for Ti–6Al–4V). Such behaviour is termed superplasticity and coupled with diffusion bonding (SPFDB), a wide range of lightweight structures can be produced. The aerospace industries exploit the SPFDB process more than any other sector. Furthermore, fine grained Ti–6Al–4V, in the order of ∼1 μm, can promote lower forming temperatures (∼750°C), reducing the amount of oxygen pick-up. This reduces the formation of an alpha case and surface embrittlement which must usually be removed via subsequent chemical etching and grit blasting.

The process can produce panels in one process. Figure 12 shows a Ti–6Al–4V panel approximately two of metres in size that has been produced in one forming cycle from a single flat sheet. Sheet thickness can be as little as 0·5 mm. Products that are manufactured via such a route include nose cones, door panels, wing tip light housings, access panels, air delivery tubes and firewall bulkheads.

Figure 12.

Ti–6Al–4V superplastically formed panel withdrawn from one of 17 presses at RTI Advanced Forming UK

Simon Bainbridge, R&D Engineer, Siemens Metals Technologies presented A case study in materials efficiency in construction steels. This re-evaluated the efficiency of the structural I-beam, which is hot rolled to shape by a Universal Beam Mill. Although developed in the late nineteenth century the fundamental design has not changed.

Simon, working with the WellMet 2050 Group at Cambridge University, concluded through finite element modelling that the I-beam was highly inefficient. Although the perfect beam (Fig. 13), would be more expensive to manufacture, weight savings would be considerable (up to 35%) which would result in less transport costs and CO₂ savings. But if more efficient beams are to be implemented, there needs to be major changes in the supply chain in what is a cost driven industry. Another drawback is that stress optimised beams cannot be reused in different structural applications, unlike traditional I-beams.

Figure 13.

‘Perfect’ beam that has up to 35 wt-% reduction over conventional I-beam

Dr Kamran Mumtaz, Lecturer, Department of Mechanical Engineering reviewed the progress in Metal additive manufacturing at The University of Sheffield. Additive manufacturing (AM) also known as three-dimensional printing is being accepted as a viable commercial alternative to conventional manufacturing processes in industries such as aerospace, automotive and medical. Additive manufacturing is capable of producing fully functional parts directly from a CAD model through joining of material layer by layer, as opposed to conventional subtractive manufacturing methodologies. The process offers excellent geometric complexity and hence provides increased design freedom allowing part performance to be optimised and enabling the production of lighter weight components.

Capabilities of metal based AM processes such as selective laser melting and electron beam melting have improved considerably over the last few years. These processes utilise high energy densities to completely melt and join materials producing fully dense structures. Metal AM parts now possess properties that are on par with those conventionally manufactured (investment cast) from a variety of metal alloys.

Limitations of AM include thermal distortion when building large complex components, poor surface finish and anisotropy of mechanical properties with respect to build-up direction. Many impressive examples were presented of AM geometries and components, including chassis bolts for the Bloodhound Project car, GE Fuel Injectors, GE titanium leading edges for fan blades, cranial implants and F1 components (Fig. 14).

Figure 14.

Ti–6Al–4V heat shields for 2010 season F1 car

Functional surfaces

Paul Morrell, Corporate Specialist Surface Engineering, Rolls-Royce provided insight into Surface coatings in aero-engine applications. He explained how surface engineering technologies are widely used in the modern gas turbine engine to maintain or maximise the performance of engines. These applications range from hard, tough coatings systems to control wear, soft abrasion resistant coating systems to allow cutting of running tracks to maintain good air sealing, through to coating systems to combat high temperature degradation such as oxidation and high temperature corrosion. He reviewed the contribution that surface engineering has made to the performance and efficiency of the gas turbine engine, from its early adoption in the 1960s to the present (Fig. 15).

Figure 15.

Type test turbine entry temperature trend and progress in materials and technology

As gas turbine engines developed and the need for increased power and efficiency drove operating temperatures ever higher, turbine alloy development focussed on the need for increased high temperature strength and good fatigue behaviour. This was largely achieved through the reduction of chromium and aluminium in high temperature alloys at the expense of the surface stability of these alloys. Early applications of surface engineering were, in the main, a response to this issue where the component did not meet the design life due to oxidation and corrosion attack

Currently, surface engineering is deployed throughout the modern gas turbine engine and is fully integrated into the design definition process at a very early stage where the cost and reliability of the components are set.

Chunjun Li, KTP Associate with Evenort Ltd in conjunction with Sheffield Hallam University presented Laser cladding of components for oil and gas applications. Inconel 625 provides high strength and resists a wide range of corrosive environments and thus is widely used in chemical, petrochemical and marine applications. However, Inconel 625 is relatively expensive and metal yields are low for machining pipeline flanges. Therefore, the aim of the KTP was to develop a thin layer of Inconel 625 cladding on a 316L stainless steel flange to provide good corrosion resistance. The technique of laser cladding was being developed for this application. In laser cladding, metal powder feeds through a nozzle and is melted by a laser beam so that the powder is metallurgically bonded onto the cheap base metal. Laser cladding enables great precision, low net heat input and potential for depositing thin clad layers (Fig. 16).

Figure 16.

Laser clad pipeline flange prototype

Results of laboratory wear testing, microhardness and corrosion testing of clad 625 all showed comparable results to bulk 625. The cladding technology is close to being a saleable product. It is envisaged that benefits of such technology will reduce materials cost between 50 and 85% and reduce manufacturing lead times.

Dr Adrian Leyland, Senior Lecture, Department of Materials Science and Engineering at The University of Sheffield reviewed Plasma processing of wear resistant surfaces for titanium. Plasma assisted processing techniques are now widely established for the production of wear resistant coatings and treatments on machine tools and engineering components.

One of the disadvantages of titanium alloys is that they have poor wear resistance, which can be improved by the creation of a plasma nitride or oxide coating. But physical vapour deposited (PVD) ceramic coatings tend to be very stiff, compared to the relatively low yield strength substrate, which leads to poor performance. Durability can be improved by oxygen and nitrogen diffusion treatment prior to coating, particularly if performed by plasma assisted techniques, which are more flexible, rapid and controllable.

Dr Leyland explained that the response of titanium alloys to such coating techniques is extremely sensitive to surface microstructure and alloy chemistry. Careful measures have to taken during the diffusion treatment to make sure that the layer is sufficiently deep to support the PVD but wihout extending coating times in order to reduce cost.

Hot filament enhanced (triode) plasma processing techniques can be used both to plasma diffusion treat and (by electron beam evaporative PVD) to duplex treat/coat selected titanium alloys. Such diffusion treatments can comprise triode plasma nitriding, triode plasma oxidation or sequential ‘oxy nitriding’; each approach can be tailored to suit individual substrate materials and applications. Examples of such coating technologies were presented and included landing gear bearings and various biomedical devices, Figure 17.

Figure 17.

A range of Ti–6Al–4V biomedical devices coated with triode plasma oxy nitriding techniques

Laser peening technology was presented by Ben Hayes, Regional Sales Manager of Curtiss Wright Surface Technologies (Metal Improvement Company). Laser peening technology has emerged as an important contributor to improved fatigue lifetimes and reduced susceptibility to stress corrosion cracking for a broad range of components that can be treated in a factory or on site.

Laser peening induces deeper levels of plasticity in materials compared to conventional surface treatments, such as shot peening. In laser peening a laser beam is imaged onto the surface of a material (spot size ranging from 3 to 1 cm). A flow of water is maintained on the surface to help confine the high pressure plasma that forms. Within a thickness of 10 μm, pressures can reach 40 000 atmospheres, which creates a shock wave that plastically deforms the metal locally. Improvements in stress corrosion cracking resistance and fatigue life enhancement were presented. The technology is being used to enhance the fatigue resistance of fan blades for commercial aircraft such as Boeing Dreamliner, B777 and A340 as well as automotive, electrical power applications.

Enabling and emerging technologies

James Farrar, Principal Engineer, Process Modelling, Wilde Analysis Ltd reviewed Current and future trends in process modelling. Over the past decades, models have been developed to predict metal flow, tool failures, defects and more. The role of simulation has been to optimise the forming design and manufacturing process controls. Metal forming processes are more advanced today than at any time in the past. The understanding of metal forming processes has been enhanced by research, simulation and process controls. There has been significant progress in applications and acceptance of simulation within the metal manufacturing community.

In the early 1990s, various processes required the simulation of sequential processes of a different pedigree. These cases were generally limited to two or three processes. On the other hand, it opened up the topic of vertical integration. During the last few years, researchers and leading users of simulation software have migrated towards simulating the entire manufacturing process. For the most part, geometry development is within the capabilities of commercial software today. On the other hand, the microstructure models are required for the prediction of mechanical properties. The strategic objective is to predict how changes in the manufacturing process will affect the performance of the finished part in service. Microstructure model development is the source of considerable and continuing effort.

He gave examples of the vision for vertical integration in metal manufacturing and some of the advanced developments in the DEFORM System to support this initiative.

Optimising design of engineering components for reducing friction and wear was presented by Professor Robert Dwyer-Joyce, Department of Mechanical Engineering, at the University of Sheffield. He explained that when designing against friction and wear it is important to keep the surfaces apart – to provide a thin low shear strength layer and the commonest way of doing this is through lubrication. Selecting the right lubricant is clearly important, but before that it is necessary to design the component so it is easy to lubricate – so that a lubricant film forms in the first place. The formation of an oil film is governed by hydrodynamics. Surfaces need to be smooth and designed with oil entraining wedge shapes. The higher the speed the more the oil can be entrained into a bearing contact, but the higher the load the more it will be squeezed out. Full film, where friction and wear will be very low, occurs down to the boundary regime where asperity contact occurs. Designing a component for low friction and wear is a five stage process:

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understanding the required duty

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design of the geometry to promote lubrication

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selecting the appropriate materials

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specifying the surface

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selection of the lubricant.

In many applications, either because lubrication is impractical, or because there is a need to use low viscosity oils (commonly used to reduce pumping losses). Then asperity contact is inevitable and the design problem becomes a little more complex. The use of hard materials (and to a certain extent low modulus materials) usually reduces wear. The use of hard surface coatings can also provide a cost effective solution.

He emphasised that predicting friction and wear in any engineering component is difficult. Any model needs to take into account complex surface properties, environmental factors, material properties, and loading conditions. This means that rigorous testing plays an important role in the design process. The hierarchy of testing common in the development of a simple component such as a piston ring is to bench test material specimens, bench test components, subassembly testing, bench test assembly, machinery bench tests and finally machinery field testing.

Kian Woodward, Market Development Manager, Tata Steel introduced Developing steel based building integrated photovoltaic products. In 2008 Tata Steel embarked on a project to investigate a method of printing photovoltaic (PV) materials onto steel strip. The ultimate aim of the project is to develop electricity generating roofing panels that will be installed on large industrial buildings, effectively turning buildings into power stations.

The European building integrated PV (BIPV) market that Tata Steel will target is predicted to reach 85–125 GW of installed capacity by 2020. Tata Steel produce over 10⁸ m² coated steel per annum that goes into the cladding of roofs and walls of large industrial buildings. The roof space of these buildings is essentially redundant and offers the ideal opportunity for the deployment of BIPV products (Fig. 18).

Figure 18.

Strategic vision – buildings as power stations: roofs are largely redundant space and can be used for deployment of BIPV products

The technology selected by Tata Steel is a third generation PV technology known as dye solar cells (DSCs). The reasons for its selection were:

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It can be coated onto a substrate in a similar way to current organic paint systems.

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The technology can be coated in atmospheric conditions.

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It uses non-toxic abundant materials.

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It can be flexible and lightweight.

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It is at an early stage of development with good potential for efficiency improvements.

The project is based in the PV Accelerator, a Tata Steel facility in Shotton, North Wales. The project involved a total investment of £11 million, part of which was funded by the Welsh Government. It is a collaborative development with the world’s leading DSC company, Dyesol. The project has now been running for four years and achieved a number of key outcomes. The core competence to exploit PV technologies have been developed and scaled-up from the laboratory to a pilot process. It has been shown that DSC offers the best long term potential in PV because of its real world performance and suitability for large scale production by atmospheric printing, and use of abundant and environmentally sustainable materials.

Dr Russell Goodall, Department of Materials Science and Engineering. University of Sheffield, demonstrated More with less – the surprising behaviour of metal foams, sponges and lattices. Following two decades of research, production of a metallic foam replication process, based on casting around a removable preform, (a relative of a sand core in a more conventional process) promises industrial scalability, and is being piloted at various locations worldwide.

The fundamental scientific understanding of the materials behaviour of foams gained during this period is now starting to lead to industrial applications. These are most frequently based on either:

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behaviours shown by metal foams that other materials do not display (e.g. the combination of a large surface area and high electrical conductivity, for electrodes)

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the ability to tailor properties through control of the porous structure, the mesostructure (e.g. the matching of properties with bone in an implant)

True foams, where each bubble is isolated are often suggested to have good weight specific mechanical properties; however, the Sheffield University team have recently explored a surface treatment process which develops a ceramic layer on open celled foam, giving up to an eightfold increase in specific strength.

Metal sponges, where all pores interconnect, are useful also for functional applications, due to the large amount of surface area they present. One example of this is in a heat exchanger, where the random structure aids mixing. It has been shown that a good balance of properties can be achieved by changing the pore size in different parts of the component.

Current advances are mostly being made in materials that can only be created using the latest processing routes. Regular, precisely designed, lattice structures can be made using additive layer manufacturing methods. These materials have the capability to be tailored with an unprecedented degree of precision, including the designing in of behaviours not normally seen in metals, such as auxetic elastic response, or negative coefficient of thermal expansion. As the processing methods are advanced, porous metals with even more novel properties are to be expected.^{Figure 3}

Closing address

Mick Steeper, Manager Technology, Siemens Metals Technologies presented an overview of IMMPETUS – Institute for Microstructural and Mechanical Process Engineering: Vision, Achievement and Legacy. A 15-year project sponsored by EPRSC at the University of Sheffield to understand the scientific underpinning for the development of physical based models to be used in the thermomechanical processing involved metallurgists, engineers and control engineers with close cooperation with industry. The aim was to integrate metallurgical, mechanical and thermal considerations to develop models for process planning and control to achieve target microstructures and product properties within increasingly fine tolerance and greater efficiency.

Posing the question; what is this underpinning idea that has become a universal methodology? Its foundation is that the properties of metals are both revealed and determined by their microstructure. This means in turn that the manufacturing of metal (and especially its hot working) is essentially a process of optimising and assuring microstructure. The corollary is that Microstructural development in the metalworking process can be scientifically described, and hence it can be modelled and controlled. Beyond these core ideas, there is an extended science of characterisation and metrology, of experimental method and modelling techniques. From the beginning, IMMPETUS dealt with this toolkit as well as with the physical metallurgy. We can see with hindsight that it did the job so comprehensively and successfully that its approach to metallurgical research has been emulated around the world.

Over those fifteen years, which come to an end in December 2012, IMMPETUS delivered 50 core PhDs and contributed significantly to around twice that number. At the peak there were in excess of 50 staff. IMMPETUS is not without its contradictions. The quality that made it special and unique, one of cooperation and partnership, waned steadily over time. The industrial partners, it can be argued, never quite embraced the whole, tending to exploit the models but seek their own control implementation.

Summary

The SMEA Conference attracted 92 delegates with a good balance of manufacturers and users and a strong representation from universities and research laboratories. The informal atmosphere provided a good opportunity for technical and social contact and networking. The excellent technical programme was supported by the Exhibition.

On the evening of Tuesday 19 June, Dr Derek Stork, Director Technology, Culham Centre for Fusion Energy presented the 2012 SMEA Celebrity Lecture to an audience of over 220. His presentation ‘Making fusion technology a reality: technology and engineering challenges’ first explained the principles of nuclear fusion, and how the plasma had to be generated and sustained, with reference to the valuable experience gained from the JET project – the world’s largest and most powerful tokamak and the focal point of the European fusion research programme. He then gave a fascinating insight of the many engineering challenges and the special materials requirements of the ITER Project – a multinational 30-year project to demonstrate the feasibility of nuclear fusion as a viable power source. This was illustrated with memorable animations of how a robot will be used to install and maintain the key components required to contain the plasma.

Following the lecture Dr Stork was presented with a commemorative pewter bowl (Fig. 19).

Figure 19.

Presentation to Celebrity Lecturer, Dr Derek Stork

In 2013 SMEA and the British Stainless Steel Association are hosting a major international conference and exhibition to celebrate the 100 years of stainless steel, which will focus on the future for stainless steel and the further contribution it can make to society.

Harry Brearley Stainless Steel Centenary Conference & Exhibition

The Development and Application of Stainless Steels

University of Sheffield, 11–13 June 2013