Improving Global Quality of Life

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An example of the value of welding to a small economy is shown by this example from New Zealand (NZ) (population 4.4 million) undertaken by an industry-based research organisation the NZ Heavy Engineering Research Association (HERA). The study has produced some interesting results, such as: An estimated 6,500 people’s work involves welding, and a further 800 people are involved as welding supervisors, engineers, or inspectors. The value added of welding and joining technology in 2007 was estimated as NZ$813 million. In 2008, around 4,000 tonnes of welding consumables (imported and locally manufactured for the local market) with an estimated total value of NZ$15 million was available on the NZ market. 3.5 Failures of welded structures Structural performance of the welded components strongly depends on the local joint quality. The welded structures are often fabricated to satisfy conflicting requirements (low cost and weight, long life and performance, limits of the technology) of material/design/technology. Additionally, welded or joined components inherently contain micro- and macro heterogeneities and stresses at the joint areas, which may contribute to the failures of the components. Prevention of failures and ensuring long and safe life of welded structures (such as offshore platforms, pipelines, steel constructions, bridges etc.) also depends on the effectiveness of the corrosion protection. Fatigue is a serious problem (see Figure 3.3) for welded structures subjected to repeated or fluctuating loading in service. Advanced design and flaw assessment guidelines are now available, however, to prevent failure of a component and ensure structural safety. Regarding the corrosion resistance of welded structures, the current guidelines and standards are predominantly related to base materials. This provides future challenges and tasks to adopt the respective practices to welded components. Furthermore, there is a need to describe the effects of the various weld microstructures and residual stresses on the resistance of components against corrosion damage and cracking. Figure 3.3 Fatigue crack propagation in laser welded aerospace Al-alloy (Reproduced courtesy: GKSS, M. Kocak) Failures of the welded components are usually due to the deterioration of the material/weld properties (development of a crack or local damage under fatigue, creep, corrosion or their combinations etc.) and/ or an increase in loading and/or localised external damage and/or change in function of the component. A satisfactory life-cycle of the welded structures requires a correct assessment of the stress levels and cycles as well as correct determination of the weld joint local properties. When weld joint failures are experienced in service (due to fatigue), it is often in cases where the acting stress levels (and overloads) are not known or have increased during the service life by far more than was foreseen at the design and fabrication stages. Strength mismatch (see Figure 3.4) between weld deposit and base metal as well as weld width (2H) play significant roles on crack tip deformation and failure behaviour of welds with respect to residual strength. This feature has now been taken into account in new codes and standards dealing with structural integrity assessment of welded structures. 14 Improving Global Quality of Life Through Optimum Use and Innovation of Welding and Joining Technologies
3 Significance of welding and joining Homogeneous Structure Strength Over-Matched Welded Structure Strength Under-Matched Welded Structure Plastic Zone Remote Plasticity at the Base Metal Confined Plasticity within Weld Zone Figure 3.4 Schematic showing the significance of yield strength mismatch on deformation and fracture behaviour under static loading (Reproduced courtesy of: GKSS, M. Kocak) In general, cause and development stages of any damage or failure process of welded structures are complex. Various factors may interact at different stages of any damage occurrence. Use of advanced modelling tools and fitness-for-service procedures at the design stages of complex welded structures could ensure structural integrity and safe operation while contributing to the economic fabrication and inspection scheme. Development of Structural Health Monitoring (SHM) systems for welded structures is still a challenge for the designers and plant operators. Furthermore, use of wireless, remote sensors with sufficient reliability to monitor large and complex structures to prevent development of a critical situation at any part of the structure require further research. This offers new opportunities and challenges for structural and other engineering disciplines. Through Optimum Use and Innovation of Welding and Joining Technologies Improving Global Quality of Life 15
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 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 42 and 43: Finally, testing of welds will be e
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
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In national or regional legal codes
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7.4.2 Optimum laws Laws applying in
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IIW needs to help ISO and others cl
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structures. It is unlikely in the s
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72 Improving Global Quality of Life
Page 88 and 89:
8. Needs and challenges for global
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infrastructure to develop multiple
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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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Improving Global Quality of Life

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