Improving Global Quality of Life

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Finally, testing of welds will be extended to all periods of the life-cycle of the welded structures. In addition to the fabrication and service phase, they will also significantly contribute to life-cycle extension (repair) procedure of the critical components. 4.2 High energy density welding processes and material response High energy density (HED) welding simply refers to Laser Beam Welding (LBW) and Electron Beam Welding (EBW) processes. The benefits offered by HED fusion welding are narrow, deep weld penetration, high welding speeds, low heat input (and hence low distortion and heat affect) and precision. EBW is somewhat mature and has various well-accepted applications including packaging (e.g. pressure sensors) and aerospace components. There have been attempts to broaden application to high production (e.g. automotive) manufacturing, but incompatibility of vacuum systems with the demands of large scale production have prevented these applications. In contrast, LBW has benefited from continual development of new laser sources with new capabilities and is somewhat more compatible with the demands of high production and large component manufacturing, so it enjoys a broader range of applications. Nonetheless, challenges of high equipment cost, lack of system portability, laser safety, lack of robustness to manufacturing environments (particularly, the need for cleanliness of optical surfaces) continue to hamper LBW applications. Smaller, more efficient laser sources or central laser generators with fibre distribution system would help with LBW portability. Practical, robust cost-competitive out-of-vacuum capability would promote EBW applications. Eliminating root defects in partial penetration LBW would assist its application, and laser systems with multiprocess capability (i.e. cut, drill, weld, machine interchangeably on the same system) would be more economical. The general need for off-line process planning for virtual manufacturing are the same as for other joining processes, but the models and needs for HED processes are unique. The continuously disappearing global resources in metals require and make it economically advantageous to join dissimilar materials according to function. Bi-metal segment saws need wear resistant teeth and a carrier for fastening. With continuous wear the teeth may be sharpened by grinding down to the holes of the rivets (Figure 4.5). High speed steel costs today 10 times more than carbon steel. It is evident, that such a bi-metal design is cost effective and works as well as made from full HSS. The preferred process with minimum energy consumption for joining is electron beam welding. Figure 4.5 Segment of a cold saw of high speed steel EB-welded to carbon steel in annealed condition. This saves 50% of the expensive highspeed steel (Reproduced courtesy: Probeam) A similar application with the same underlying concept is EB welding of worm gears consisting of bronze and steel. The expensive bronze is only used where its lubricating characteristics and wear resistance are required at the outer circumference. There are many such examples already taking place today and with rising material cost, in the future, these applications of joining dissimilar materials will increase. Figure 4.6 Combination of steel and bronze, 30 mm deep electron beam weld (Reproduced courtesy: Probeam) 28 Improving Global Quality of Life Through Optimum Use and Innovation of Welding and Joining Technologies
4 Needs and challenges in welding and joining technologies Another area of improvement of efficiency is the increase of temperature of combustion in any kind of gas turbines. The related materials, for example Ti-alloys in aircraft engines, Cr-steels in steam turbines or super alloys in the helium driven turbine for the 2020 pebble bed reactor all require special welding processes. These have to be energy efficient and adaptable to the metallurgical needs of the related materials. Figure 4.7 Bronze-steel or bronze-cast iron combinations are an economic method to produce worm gears (Reproduced courtesy: Probeam) Welding of heavy gauge sections bears a tremendous potential of materials and energy saving. It should be expected that EB-welding will be the process of choice for such visionary applications, already under development now. Figure 4.8 Housing of a gas turbine being prepared for EB welding (Reproduced courtesy: Probeam) An education aspect of the EB welding process will be a serious challenge for coming decades. For successful and wider implementation of the EB welding (which involves high degree of application flexibility) there exists a need for more intense communication and transparency to the potential end-users. 4.3 Repair welds and material response In order to extend service life of aging welded structures, there is need for advanced welding technologies for repair. Most of the repair welding procedures are principally different from welding during fabrication regarding the parameters, the weld sequences as well as the metallurgical conditions and the design features. This means that ideal welding conditions cannot always be achieved during repair welding. Additionally, poor material conditions of the component segments to be repaired might result from previous service operation. Here, advanced welding simulation technologies need to be developed to predict final microstructural conditions and the residual stress state of the repaired area to achieve optimum repair welding procedures and prevent further problems. Through Optimum Use and Innovation of Welding and Joining Technologies Improving Global Quality of Life 29
Page 1 and 2: Improving Global Quality of Life Th
Page 3 and 4: Foreword Dr Baldev Raj Mr Chris Sma
Page 5 and 6: In alphabetical order (Continued) D
Page 8 and 9: 6.3 Job, skill, career and competen
Page 10 and 11: 9.6.3 Welding processes and challen
Page 12 and 13: Executive summary “ Welding is an
Page 14 and 15: Editors’ Preface Improving Global
Page 16 and 17: Scope and objectives 1 an important
Page 18 and 19: Welding industry 2.in the world 2.1
Page 20 and 21: 2.2 Today’s welding industry and
Page 22 and 23: 2 Welding industry in the world IIW
Page 24 and 25: 3.welding Signifi cance of and join
Page 26 and 27: 3.3 Welding and joining in sustaina
Page 28 and 29: An example of the value of welding
Page 30 and 31: 16 Improving Global Quality of Life
Page 32 and 33: 4. Needs and challenges in welding
Page 34 and 35: Welding thick walled steel componen
Page 36 and 37: The trend towards light-weight desi
Page 38 and 39: Up-to-date, titanium alloys have be
Page 40 and 41: Needs for weight reduction in aircr
Page 44 and 45: As another most important item, the
Page 46 and 47: In order to make the developments i
Page 48 and 49: Reduction and/or elimination of dis
Page 50 and 51: 5. Needs and challenges in welding
Page 52 and 53: The productivity in EB welding has
Page 54 and 55: The potential applications are for
Page 56 and 57: 5.2 Higher automation, productivity
Page 58 and 59: In submerged arc welding one can re
Page 60 and 61: From a practical perspective, the n
Page 62 and 63: Acceptance levels are not included
Page 64 and 65: 5.5 NDT and structural health monit
Page 66 and 67: IIW can help companies to get their
Page 68 and 69: 6. Needs and challenges in health,
Page 70 and 71: welder against Cr6 is a very import
Page 72 and 73: is considerable national concern fo
Page 74 and 75: important in meeting needs with res
Page 76 and 77: 7. Legal codes, rules and standardi
Page 78 and 79: In national or regional legal codes
Page 80 and 81: 7.4.2 Optimum laws Laws applying in
Page 82 and 83: IIW needs to help ISO and others cl
Page 84 and 85: structures. It is unlikely in the s
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Page 88 and 89: 8. Needs and challenges for global
Page 90 and 91: infrastructure to develop multiple
Page 92 and 93:
Table 8.1 Key actions and key activ
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80 Improving Global Quality of Life
Page 96 and 97:
9.7.1 Hot topics ..................
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New discoveries tend to be in deepw
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Proved reserves at end 2004 Trillio
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easily weldable, the life expectanc
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9.1.3 Hot topics Reducing negative
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Following these codes assures initi
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9.1.5 Hot topics Development and up
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9.1.8 Power - Renewable Rising fuel
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9.2.2 Production using joining tech
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still sometimes an unanswered quest
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2. To an increasing extent, joining
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nature and not specifically related
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9.3.2 Hot Topics The following issu
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industry have resulted in the need
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technology based on the existing pi
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general investment climate, includi
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10 000 Eq. SS range, MPa 1000 100 1
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Globalisation: PEI is operating in
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At the same time as automakers are
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On the other hand, when looking at
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9.7.2 Welding in the minerals proce
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Finland Poland Rest of the world Cr
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This situation is unsatisfactory an
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implementation of smart systems. In
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9.9.2 Hot topics Raising and enforc
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9.10.2 Welding industry role As des
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While items and directions may vary
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9.11.2 Hot topics In spite of these
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9.13.2 Preheat Preheating is carrie
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The electronic products industry se
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Portable power: In the Portable Pow
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the HRI report which accounted for
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9.16.2 Joining live tissues and coa
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(material removal, welding, surface
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Furthermore, in the field of dissim
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9.20 Small and medium enterprises
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and assessment. Multi-material desi
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0. Short, medium and long-term stra
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10.3.2 Typical hot topics In the me
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10.4 Long-term strategic agenda IIW
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162 Improving Global Quality of Lif
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[16] Mayr P et al., “Long-term cr
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IIW White Paper - Edition 2012 ISBN
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