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Research Papers: Materials and Fabrication

High Temperature, Low Cycle Fatigue Characterization of P91 Weld and Heat Affected Zone Material

[+] Author and Article Information
T. P. Farragher

Mechanical Engineering,
College of Engineering and Informatics,
NUI Galway,
Galway, Ireland

S. Scully

ESB Energy International,
ESB Head Office,
27 FitzWilliam Street,
Dublin 2,
Dublin, Ireland

N. P. O'Dowd

Department of Mechanical, Aeronautical,
and Biomedical Engineering,
Materials and Surface Science Institute,
University of Limerick,
Limerick, Ireland

C. J. Hyde

Department of Mechanical, Materials
and Manufacturing Engineering,
University of Nottingham,
Nottingham NG7 2RD, UK.

S. B. Leen

Mechanical Engineering,
College of Engineering and Informatics,
NUI Galway,
Galway, Ireland

Contributed by the Pressure Vessel and Piping Division of ASME for publication in the JOURNAL OF PRESSURE VESSEL TECHNOLOGY. Manuscript received May 25, 2013; final manuscript received October 16, 2013; published online January 8, 2014. Assoc. Editor: Marina Ruggles-Wrenn.

J. Pressure Vessel Technol 136(2), 021403 (Jan 08, 2014) (10 pages) Paper No: PVT-13-1088; doi: 10.1115/1.4025943 History: Received May 25, 2013; Revised October 16, 2013

The high temperature low cycle fatigue behavior of P91 weld metal (WM) and weld joints (cross-weld) is presented. Strain-controlled tests have been carried out at 400 °C and 500 °C. The cyclic behavior of the weld material (WM) and cross-weld (CW) specimens are compared with previously published base material (BM) tests. The weld material is shown to give a significantly harder and stiffer stress–strain response than both the base material and the cross-weld material. The cross-weld tests exhibited a cyclic stress–strain response, which was similar to that of the base material. All specimen types exhibited cyclic softening but the degree of softening exhibited by the cross-weld specimens was lower than that of the base material and all-weld tests. Finite element models of the base metal, weld metal and cross-weld test specimens are developed and employed for identification of the cyclic viscoplasticity material parameters. Heat affected zone (HAZ) cracking was observed for the cross-weld tests.

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References

Hyde, T. H., and Sun, W., 2005, “A Study of Anisotropic Creep Behaviour of a 9CrMoNbV Weld Metal Using Damage Analyses With a Unit Cell Model,” Proc. Inst. Mech. Eng., Part L, 219, pp. 193–206.
Spiarelli, S., and Quadrini, E., 2002, “Analysis of the Creep Behaviour of Modified P91 Welds,” Mater. Des., 23, pp. 547–552. [CrossRef]
Tabuchi, M., Hongo, H., Li, Y., Wantanabe, T., and Takahashi, Y., 2009, “Evaluation of Microstructures and Creep Damages in the HAZ of P91steel Weldment,” ASME Int. J. Pressure Vessels Technology, 131(2), p. 021406. [CrossRef]
Watanabe, T., Tabuchi, M., Yamazaki, M., Hongo, H., and Tanabe, T., 2006, “Creep Damage Evaluation of 9Cr–1Mo–V–Nb Steel Welded Joints Showing Type IV Fracture,” Int. J. Pressure Vessels Piping, 83, pp. 63–71. [CrossRef]
Kimura, K., Tabuchi, M., Takahashi, Y., and Yagi, K., 2011, “Long-Term Creep Strength and Strength Reduction Factor for Welded Joints of ASME Grades 91, 92, and 122 Type Steels,” Int. J. Microstruct. Mater. Prop., 6, pp. 72–90.
Gaffard, V., Gourgues, A. F., and Besson, J., 2005, “High Temperature Creep Flow and Damage Properties of 9Cr1MoNbV Steels: Base Metal and Weldment,” Nucl. Eng. Des., 235, pp. 2547–1562. [CrossRef]
Li, Y., Hongo, H., Tabuchi, M., Takahashi, Y., and Monma, Y., 2009, “Evaluation of Creep Damage in Heat Affected Zone of Thick Welded Joint for Mod.9Cr-1Mo Steel,” Int. J. Pressure Vessels Piping, 86, pp. 585–592. [CrossRef]
Das, C. R., Albert, S. K., BhaduriA. K., SrinivasanG., and Murty, B. S., 2008, “Effect of Prior Microstructure on Microstructure and Mechanical Properties of Modified 9Cr-1Mo Steel Weld Joints,” Mater. Sci. Eng., A, 477, pp. 185–192. [CrossRef]
EBI, G., and McEvily, A. J., 1984, “Effect of Processing on the High Temperature Low Cycle Fatigue Properties of Modified 9Cr-1Mo,” Fatigue Fract. Eng. Mater. Struct., 7, pp. 299–314. [CrossRef]
Gieseke, B. G., Brinkman, C. R., and Maziasz, P. J., 1993, The Influence of Long Term Thermal Ageing on the Microstructure and Mechanical Properties of Modified 9Cr-1M0 Steel, P. K.Liaw, R.Viswanathan, K. L.Murty,E. P.Simonen, and D.Frear, eds., The Minerals, Metals and Materials Society, pp. 107–115.
Shankar, V., Valsan, M., Bhanu Sankara Rao, K., Kannan, R., Mannan, S. L., and Pathak, S. D., 2006, “Low Cycle Fatigue Behaviour and Microstructural Evolution of Modified 9Cr-1Mo Ferritic Steel,” Mater. Sci Eng., A, 437(2), pp. 413–422. [CrossRef]
Fournier, B., Sauzay, M., Caës, C., Noblecourt, M., and Mottot, M., 2006, “Analysis of Hysteresis of a Martensitic Steel, Part I: Study of the Influence of Strain Amplitude and Temperature Under Pure Fatigue Loadings Using Enhanced Stress Partitioning Method,” Mater. Sci Eng., A, 437, pp. 183–196. [CrossRef]
Fournier, B., Sauzay, M., Caës, C., Noblecourt, M., Mottot, M., and Pineau, A., 2006, “Analysis of Hysteresis of a Martensitic Steel, Part II: Study of the Influence of Creep and Stress Relaxation Holding Times on Cyclic Behaviour,” Mater. Sci. Eng., A, 437, pp. 197–211. [CrossRef]
Yang, H. C., Tu, Y., Yu, M. M., and Zhao, J., 2009, “Investigation of the Low-Cycle Fatigue and Fatigue Crack Growth Behaviours of P91 Base and Weld Joints,” Acta Metall. Sin. (Engl. Lett.), 17(4), pp. 597–600.
Mannan, S. L., and Valsan, M., 2006, “High-Temperature Low Cycle Fatigue, Creep-Fatigue, and Thermomechanical Fatigue of Steels and Their Welds,” Int. J. Mech. Sci., 48, pp. 160–175. [CrossRef]
Takahashi, Y., 2006, “Study on Type-IV Damage Prevention in High-Temperature Welded Structures of Next-Generation Reactor Plants, Part I: Fatigue and Creep-Fatigue Behaviour of Welded Joints of Modified 9Cr-1Mo Steel,” ASME PVP Conference, Canada.
Shankar, V., Valsan, M., Bhanu Sankara Rao, K., and Pathak, S. D., 2010, “Low Cycle Fatigue and Creep-Fatigue Interaction Behaviour of Modified 9Cr-1Mo Ferritic Steel and Its Weld Joint,” Trans. Indian Inst. Met., 63, pp. 622–628. [CrossRef]
Shankar, V., Sandhya, R., and Mathew, M. D., 2011, “Creep-Fatigue-Oxidation Interaction in Grade 91 Steel Weld Joints for High Temperature Applications,” Mater. Sci. Eng., A, 528, pp. 8428–8437. [CrossRef]
Sandhya, R., Kannan, R., Ganesan, V., Valsan, M., and Bhanu Sankara Rao, K., 2010, “Low Cycle Fatigue Properties of Modified 9Cr-1Mo Ferritic Martensitic Steel Weld Joints in Sodium Environment,” Trans. Indian Inst. Met., 63, pp. 553–557. [CrossRef]
Saad, A. A., 2012, “Cyclic Plasticity and Creep of Power Plant Materials,” Ph.D. thesis, University of Nottingham, Nottingham, UK.
Saad, A. A., Hyde, C. J., Sun, W., and Hyde, T. H., 2011, “Thermal-Mechanical Fatigue Simulation of a P91 Steel in a Temperature Range of 400–600 °C,” Mater. High Temp., 28(3), pp. 212–218. [CrossRef]
Farragher, T. P., Hyde, C. J., Sun, W., Hyde, T. H., O'Dowd, N. P., Scully, S., and Leen, S. B., 2012, “High Temperature Low Cycle Fatigue Behaviour of Service-Aged P91 Material,” 9th International Conference on Creep and Fatigue at Elevated Temperatures, IOM3, London, UK.
Hyde, C. J., Sun, W., Hyde, T. H., Rouse, J. P., Farragher, T. P., O'Dowd, N.P., and Leen, S. B., 2012, “Cyclic Visco-Plasticity Testing and Modelling of a Service-Aged P91 Steel,” Proceedings of the ASME 2012, Pressure Vessels and Piping Division Conference, ASME, July 15–19, 2012, Ontario, Canada, Report No. PVP2012-78460.
Deshpande, A. A., Hyde, T. H., and Leen, S. B., 2010, “Experimental and Numerical Characterization of the Cyclic Thermo-Mechanical Behaviour of a High Temperature Forming Tool Alloy,” ASME J. Manuf. Sci. Eng., 132(6), p. 051013. [CrossRef]
Farragher, T. P., Scully, S., O'Dowd, N. P., and Leen, S. B., 2012, “Thermomechanical Analysis of a Pressurised Pipe Under Plant Conditions,” ASME J. Pressure Vessel Technol., 135(1), p. 011204. [CrossRef]
Farragher, T. P., Scully, S., O'Dowd, N. P., and Leen, S. B., 2013, “Development of Life Assessment Procedures for Power Plant Headers Operated Under Flexible Loading Scenarios,” Int. J. Fatigue, 49, pp. 50–61. [CrossRef]
Lemaitre, J., and Chaboche, J. L., 1990, Mechanics of Solid Materials, Cambridge University, Cambridge, UK. [CrossRef]
Saad, A. A., Sun, W., Hyde, T. H., and Tanner, D. W. J., 2011, “Cyclic Softening Behaviour of a P91 Steel Under Low Cycle Fatigue at High Temperature,” Proceedings from ICM11, Eng. Procedia, Vol. 10, pp. 1103–1108.
Fournier, B., Sauzay, M., Renault, A., Barcelo, F., and Pineau, A., 2009, “Microstructural Evolutions and Cyclic Softening of 9%Cr Martensitic Steels,” J. Nucl. Mater., 386(8), pp. 71–77.

Figures

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Fig. 1

Photograph of weld, positioned within a section of the P91 header material

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Fig. 2

Test specimen geometry (all dimensions in mm)

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Fig. 3

Representation of specimen position within a welded section of the header showing (a) the all-weld specimen and (b) the cross-weld specimen positions (all dimensions in mm)

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Fig. 4

Measured first cycle (N = 1) WM stress–strain response at 400 °C

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Fig. 5

Measured first cycle (N = 1) CW stress–strain response at 400 °C

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Fig. 6

WM cyclic softening behavior at 400 °C

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Fig. 7

CW stress–strain response at N = 1 at a temperature of 500 °C for various strain ranges

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Fig. 8

CW cyclic softening behavior at 500 °C

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Fig. 9

Comparison between BM, WM, and CW stress–strain response (1st cycle) for various strain ranges at a constant strain rate of 0.033%/s for 400 °C (Figs. 9(a) and 9(b)) and 500 °C (Figs. 9(c) and 9(d))

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Fig. 10

Cyclic stress-plastic strain curves for BM, WM and CW tests at 400 °C at half-life

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Fig. 11

Cyclic stress-plastic strain curves for BM, WM and CW tests at 500 °C at half-life

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Fig. 12

Stress relaxation data for different specimen types, held at a maximum tensile strain of 0.5% for a period of 120 s

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Fig. 13

Optical micrograph of (a) primary crack (occurring in the HAZ) and (b) magnified view of primary crack along with secondary (surface) cracking for cross-weld specimen tested at 1% strain range at 500 °C

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Fig. 14

Hardness traverse across (post test) CW specimen

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Fig. 15

Micrographs taken at different locations across the CW specimen of Fig. 14, showing (a) WM microstructure, (b) BM microstructure, (c) WM—fine grain HAZ fusion boundary, and (d) coarse grain HAZ, intercritical HAZ and BM boundaries.

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Fig. 16

Rheological diagram of two-layer viscoplasticity model, adapted [24]

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Fig. 17

Representation of FE models showing (a) BM single-material model, (b) WM single-material model, and (c) multimaterial CW model

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Fig. 18

Identification of C and γ for WM at 400 °C and 500 °C

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Fig. 19

Comparison of half-life experimental and NLKH WM responses at 500 °C

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Fig. 20

Comparison of half-life experimental and NLKH CW responses at 500 °C

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Fig. 21

Comparison of predicted isotropic and measured softening behavior for WM and BM at 500 °C

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Fig. 22

Comparison of predicted (combined isotropic-NLKH) and measured CW response at 500 °C for N = 1

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Fig. 23

Comparison of softening behavior predicted by the two-layer viscoplasticity CW model and measured softening behavior for the CW test at 500 °C at Δε = 0.8%

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Fig. 24

Stress relaxation behavior of CW test, compared against the stress relaxation response of the CW FE model at 500 °C

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Fig. 25

Validation cyclic two-layer viscoplasticity model for WM at N = 1 and at the half-life, at a temperature of 500 °C and for Δε = 0.8%

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Fig. 26

Comparison of FE-predicted (cyclic viscoplasticity) and measured CW response at N = 1 at 500 °C for two strain ranges

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Fig. 27

Comparison of FE-predicted (cyclic viscoplasticity) and measured CW response at half-life (softened) 500 °C for Δε = 0.8%

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Fig. 28

Comparison between predicted HAZ stress–strain response and measured BM, WM, and CW responses at N = 1

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