Abstract
Welds form an integral part of most power and chemical plant structures. At elevated temperature, the service lives of these structures are often governed by the creep behaviour in localised regions of the welds. Efforts have been made to understand the characteristic features of the creep stress distributions in and the deformation behaviour of welds and to predict the failure life. One of the major factors that affects the life of a weldment is the creep behaviour of the weld metal and the related failures due to cracking within the weld metal which has been identified in practice. The intrinsic macroscopic anisotropy of the weld metal is related to the nature of the welding process.
In this paper, the high temperature creep and creep rupture behaviours of a 9CrMoNbV weld metal, at 65°C, are reported. Uniaxial creep and creep rupture and Bridgman notched bar creep rupture tests were performed, using test specimens removed from two directions, i.e. longitudinal and transverse, with respect to the welding direction. From the test results obtained, the differences in the creep ductility, minimum creep strain rate, rupture strength and notch strength sensitivity behaviour of the material in the two directions, are identified. Material constants, in creep and damage constitutive equations, were obtained from the test data. Metallurgical studies were conducted with the aim of gaining an understanding of the difference in the creep failure mechanisms in the two directions which cause the anisotropy. The results obtained clearly indicate that anisotropy of the weld metal creep properties exists and that this anisotropy will need to be considered in numerical modelling of P91 welds, joined by the same or similar weld steels, if accurate predictions are to be obtained.
Access this chapter
Tax calculation will be finalised at checkout
Purchases are for personal use only
Preview
Unable to display preview. Download preview PDF.
Similar content being viewed by others
References
Brett, S. J. (1994). Cracking experience in steam pipework in National Power, VGB. Conf. on Materials and Weld Technology in Power Plants, Essen, Germany.
Cerjak, H. and Letofsky, E. (1998). Behaviour of advanced 9–12 Cr steels and its weldments in short and long term tests, in R. Viswanathan and J. Nutting (eds), Advanced Heat Resistant Steels for Power Generation, pp. 611–632.
Coleman, M. C. and Miller, D. A. (1994). Inspection, assessment and repair strategies for Type IV cracking in power plant components, AWS/EPPI Conference, Orlando, Florida, pp. 5–15.
Easterling, K. (1992). Introduction to the physical metallurgy of welding, Butterworth/Heinemann, London.
Evans, G. M. and Bailey, N. (1997). Metallurgy of basic weld metal, Abington Publishing.
Evans, R. W. and Wilshire, B. (1985). Creep of metals and alloys, Technical report, Institute of Metals, London.
Hall, F. R. and Hayhurst, D. R. (1991). Continuum damage mechanics modelling of high temperature deformation and failure in a pipe weldment, Proc. Royal Soc. London (A443): 383–403.
Hasegawa, Y., Ohgami, M. and Okamura, Y. (1998). Creep properties of heat affected zone of weld in W containing 9–12% Chromium creep resistant martensitic steels at elevated temperature, in R. Viswanathan and J. Nutting (eds), Advanced Heat Resistant Steels for Power Generation.
Hayhurst, D. R. (1972). Creep rupture under multi-axial states of stress, J. Mech. Phys. Solids (20): 381–390.
Hayhurst, D. R. (2000). Computational continuum damage mechanics: It use in the prediction of creep in structures — past, present and future, in S. Murakami and N. Ohno (eds), Proc. of IUTAM Symposium on Creep in Structures, Kluwer Academic Publishers, pp. 175–188.
Hayhurst, D. R., Dimmer, P. R. and Morrison, C. J. (1984). Development of continuum damage in the creep rupture of notched bars, Phil. Trans. R. Soc. London (A 311): 103–129.
Hickey, J. J., Bernard, P. J. and Bissell, A. M. (1996). Investigation and repair of a failed seam welded reheater outlet header, 2nd. Int. EPRI Conf. on Welding and Repair Technology of Power Plants, Daytona Beach, Florida.
Hull, D. (1999). Fractography: Observing, measuring and interpreting fracture surface topography, CUP.
Hyde, T. H., Sun, W. and Becker, A. A. (1999). Failure prediction for multi-material creep test specimens using a steady-state creep rupture stress, Int. J. Mech. Sci. 42(3): 401–23.
Hyde, T. H., Sun, W. and Becker, A. A. (2001). Creep crack growth in welds: A damage mechanics approach to predicting initiation and growth of circumferential cracks, Int. J. Pressure Vessel & Pi** 78(11–12): 765–771.
Hyde, T. H., Sun, W., Becker, A. A. and Williams, J. A. (1997). Creep continuum damage constitutive equations for the parent, weld and heat-affected zone materials of a service-aged l/2Crl/2Mol/4V: 2 l/2CrlMo multi-pass weld at 640°C, J. Strain Anal. 32(4): 273–285.
Hyde, T. H., Sun, W. and Tang, A. (1998). Determination of material constants in creep constitutive damage equations, Strain pp. 83–90.
Hyde, T. H., **a, L. and Becker, A. A. (1996). Prediction of creep failure in aeroengine materials under multi-axial stress states, Int. J. Mech. Sci. 38(4): 385–403.
Kachanov, L. M. (1958). Izv. AN SSSR. Otd. tekh. nauk. MM (8): 26.
Nonaka, I., Ito, T., Ohtsuki, S. and Takagi, Y. (2000). 2ndHIDA Conf. on Advances in Defect Assessment of High Temperature Plant, Stuttgart, Germany.
Orr, J. and Burton, D. (1992). Experience in data collection and assessment for material standards, CEC ECSC Information Day on The Manufacture and Properties of Steel 91 for the Power Plant and Process Industries, VDEh, Dusseldorf.
Perrin, I. J. and Hayhurst, D. R. (1996). Creep constitutive equations for 0.5Cr0.5Mo0.25V ferritic steel in the temperature range 600–675°C, J. Strain Anal. 31: 299–314.
Reed, R. C. and Bhadesia, H. K. D. H. (1994). A simple model for multipass welds, Acta Metall. Mater. 42(11): 3663–3678.
Robinson, D. N. and Swindeman, R. W. (1982). Unified creep plasticity constitutive equations for 2.25 CrlMo steel at elevated temperatures, ORNL Report TM8444, ORNL, Tenn., USA.
Schuller, H. J., Hagn, L. and Woitscheck, A. (1974). Cracking in the weld region of shaped components in hot steam pipelines — material investigations, Der Maschinenschaden 47: 1–13.
Storesund, J., Andersson, P., Samuelson, L. A. and Segle, P. (1997). Prediction of creep cracks in low alloy steel pipe welds by use of the continuum damage mechanics approach, in R. K. Penny (ed.), 4th Int. Colloquium on Ageing of Materials and Methods for the Assessment of Lifetimes of Engineering Plant, Cape Town, South Africa, pp. 129–144.
Stout, R. D. (1987). Weldability of steels, 4th edn, Welding Research Council, New York, USA.
Watanabe, T., Yamazaki, M., Hongo, H., Kinugawa, J., Tanabe, T. and Monma, Y. (1999). Long-term creep rupture properties and microstructure of weld metal on 2.25Cr-lMo steel thick plate, J. Soc. Mat. Sci. 48(2): 122–129.
Wolstenholme, A. A. (1978). Transverse cracking and creep ductility of 2CrMo weld metals, Conf. “Trends in Steels and Consumables for Welding”, The Welding Institute, Abingdon, UK.
Yamazaki, M., Hongo, H., Watanabe, T., Kinugavva, J., Tanabe, T. and Monma, Y. (1999). Heterogeneity of creep properties of welds in 304 stainless steel plate, J. Soc. Mat. Sci. 48(2): 110–115.
Author information
Authors and Affiliations
Editor information
Editors and Affiliations
Rights and permissions
Copyright information
© 2003 Springer-Verlag Berlin Heidelberg
About this paper
Cite this paper
Hyde, T.H., Sun, W., Agyakwa, P.A., Shipway, P.H., Williams, J.A. (2003). Anisotropic Creep and Fracture Behaviour of a 9CrMoNbV Weld Metal at 650°C. In: Skrzypek, J.J., Ganczarski, A.W. (eds) Anisotropic Behaviour of Damaged Materials. Lecture Notes in Applied and Computational Mechanics, vol 9. Springer, Berlin, Heidelberg. https://doi.org/10.1007/978-3-540-36418-4_9
Download citation
DOI: https://doi.org/10.1007/978-3-540-36418-4_9
Publisher Name: Springer, Berlin, Heidelberg
Print ISBN: 978-3-642-05587-4
Online ISBN: 978-3-540-36418-4
eBook Packages: Springer Book Archive