The long term reliable, safe and economic operation of power plants is highly topical in view of the need worldwide to ensure secure, efficient power supplies. Meeting these objectives requires improved high temperature structural integrity assessment methodologies. In seeking enhanced performance, as well as improved condition monitoring of materials and components in service, the development of advanced and novel methods of structural integrity assessment remains a challenge for researchers and technologists. The increasing number of aging plants in developed countries emphasises particularly the need for improved understanding of material behaviour in service-critical components. Here, the potential early failure of weldments has become a specific concern. In addition, due to the intermittent nature of renewable energy generation, conventional power generation plants are now subjected to a higher frequency of thermo-mechanical cycling, as demanded by ‘flexible operation’. The introduction of frequent cyclic operation will increase the possibility of thermal–mechanical fatigue of critical components in these plants.
Research underpinning progress in many of these topics was addressed at the 4th International Conference on Structural Integrity of High Temperature Welds, and the 9th International Conference on Creep and Fatigue at Elevated Temperatures, held concurrently on 24–27 September 2012 in London. The meeting was organised by IoMCitation3 and sponsored by IMechE, through an UK Organising Committee which was supported by an International Advisory Board.
This thematic issue of MST presents a selection of peer reviewed articlesCitation1–Citation11 from the conference, focusing on recent advances in creep, fatigue, damage and fracture analysis of high temperature material and welds. The 11 papers presented report both original research and industrial experience. The wide range of topics covered includes: finite element failure and crack growth modelling of parent materials and welds using creep continuum damage models;Citation1,Citation5 effect of creep deformation on Z-phase formation,Citation2 creep deformation, rupture and ductility of weld metals;Citation3 damage behaviour characterisation under creep–fatigue for nickel based superalloys;Citation4 creep cavitation in stainless steels;Citation6 creep micro- and macro-damage in notched bars;Citation7 micro-mechanical creep analysis of multi-pass welds;Citation8 determination of heat affected zone creep properties using small punch creep testing;Citation10 and thermal–mechanical fatigue analysis for power plant steels using visco-plasticity models.Citation9,Citation11 The majority of these topics are relevant to power plant materials (P91, P92, stainless steels and nickel based superalloys) and the structural integrity of components with an emphasis on welds.
We would like to thank the authors, referees and conference organisers who have contributed to the publication of this special issue. Thanks are also due to Maney Publishing and Mark Hull for their sponsorship and support.
A complementary selection of papers on structural assessment under high temperature fatigue and creep, with an emphasis on power plant applications, appeared in a recent Energy Materials issue of Materials Research Innovations.Citation12
W. Sun, A. A. Becker and T. H. Hyde
Guest Editors
University of Nottingham, UK
References
- Tanner D.W.J., Puliyaneth M., Sun W. and Hyde T.H.: ‘Creep damage modelling of a P92 pipe weld at 675°C’, Mater. Sci. Technol., 2014, 30, 6–11.
- Sawada Kota, Kushima Hideaki, Tabuchi Masaaki and Kimura Kazuhiro: ‘Effect of creep deformation on Z-phase formation in Grade 91 steel’, Mater. Sci. Technol., 2014, 30, 12–16.
- Spindler M.W. and Spindler S.L.: ‘Creep deformation, rupture and ductility of Esshete 1250 weld metal’, Mater. Sci. Technol., 2014, 30, 17–23.
- Kobayashi Daisuke, Miyabe Masamichi, Kagiya Yukio, Nagumo Yoshiko, Sugiura Ruji, Matsuzaki Takashi and Toshimitsu Yokobori A.: ‘Analysis of damage behaviour based on the EBSD method under creep-fatigue conditions for polycrystalline nickel-base superalloys’, Mater. Sci. Technol., 2014, 30, 24–31.
- Wen Jian-Feng, Tu Shan-Tung, Gao Xin-Lin and Reddy J.N.: ‘A new model for creep damage analysis and its application to creep crack growth simulations’, Mater. Sci. Technol., 2014, 30, 32–37.
- Jazaeria H., Boucharda P.J., Hutchingsa M. and Lindnerb P.: ‘Study of creep cavitation in a stainless steel weldment’, Mater. Sci. Technol., 2014, 30, 38–42.
- Shigeyama Haruhisa, Sugiura Ryuji, Matsuzaki Takashi and Toshimitsu Yokobori A.: ‘Micro and macro creep damage formation for P92 under multi-axial stress related to circular notched specimen’, Mater. Sci. Technol., 2014, 30, 43–49.
- Lvov I., Naumenko K. and Altenbach H.: ‘Micro-mechanical analysis of creep behaviour in a multipass weld’, Mater. Sci. Technol., 2014, 30, 50–53.
- Rouse J.P., Hyde C.J., Sun W. and Hyde T.H.: ‘Pragmatic optimisation methods for determining the material constants of a visco-plasticity model from isothermal experimental data’, Mater. Sci. Technol., 2014, 30, 54–62.
- Holmström S., Auerkari P., Hurst R., Blagoeva D.: ‘Using small punch test data to determine creep strain and strength reduction properties for heat affected zones’, Mater. Sci. Technol., 2014, 30, 63–66.
- Barrett R.A., O'Donoghue P.E., Leen S.B.: ‘A multi-axial cyclic viscoplasticity model for high temperature fatigue of P91 steel’, Mater. Sci. Technol., 2014, 30, 67–74.
- Sun W., Becker A.A. and Hyde T.H.: ‘Materials and structural assessment under high temperature creep and fatigue’, Mater. Res. Innov., 2013, 17, 298–299.