Creep Life Forecasting of Weldment
Subject Areas : EngineeringJ Jelwan 1 , M Chowdhry 2 , G Pearce 3
1 - Department of Mechanical Engineering and Manufacturing, University of New South Wales, Sydney, Australia
2 - Department of Mechanical Engineering and Manufacturing, University of New South Wales, Sydney, Australia
3 - Department of Mechanical Engineering and Manufacturing, University of New South Wales, Sydney, Australia
Keywords: Finite Element Analysis, Creep, Strain energy density, Weld, Stress/Strain analysis, Failure prediction,
Abstract :
One of the yet unresolved engineering problems is forecasting the creep lives of weldment in a pragmatic way with sufficient accuracy. There are number of obstacles to circumvent including: complex material behavior, lack of accurate knowledge about the creep material behavior specially about the heat affected zones (HAZ),accurate and multi-axial creep damage models, etc. In general, creep life forecasting may be categorized into two groups, viz., those that are based on microscopic modeling and others that are based on macroscopic (phemenological) concepts. Many different micro-structural processes may cause creep damage .The micro-structural processes highlight the fact that the creep damages can be due to cavity nucleation and growth. Dislocation creep is another mechanism with micro-structural features such as sub-grain formation and growth, new phase formation, such as the Z phase, coarsening leading to the dissolution of the MX phase. This leads to the removal of pinning precipitates, which allow local heterogeneous sub-grain growth, weakening due to this growth and also to the dissolution of the MX. These features normally lead to the earlier formation of tertiary creep and reduced life. Considering welded joints ,the development of models for practical yet sufficiently accurate creep life forecasting based on micro-structural modeling becomes even more complicated due to variation of material in the base, weld and heat-affected-zone (HAZ) and variation of the micro-structure within HAZ and their interactions. So far, and until this date, none of the micro-structural models can forecast the creep life of industrial components with sufficient accuracy in an economic manner. There are several macroscopic (phemenological) models for creep life forecasting, including: time-fraction rule, strain-fraction rule, the reference stress and skeletal stress method, continuum damage model, etc. Each of which has their own limitations .This paper gauges to a multi-axial yet pragmatic and simple model for creep life forecasting weldment operating at high temperature and subjected to an elastic-plastic-creep deformation.
[1] Portevin A., CR Acad C.,1923, Science 176: 507.
[2] Sawada K., Kubo K., Abe F., 2001, Creep behavior and stability of MX precipitates at high temperature in 9Cr-0.5Mo-1.8W-VNb steel. Materials Science and Engineering A 319-321: 784-787.
[3] R5, 1995, Assessment Procedure for the High Temperature Response of Structures, Berkely Technology Center, Nuclear Electric plc, (Issue 2).
[4] ASME S., III, Rules for Construction of Nuclear Power Plant Components, ASME,USA, 2009, Division 1, Sub-Section NH, Class 1 Components in Elevated Temperature Service.
[5] Zarrabi K., J.J., Mamood T., 2010, A Mesoscopic damage model for predicting the plastic-creep life of welded joints subjected to quasi-static loading, Proceedings of ASME IMECE, ASME 2010 International Mechanical Engineering,Congress and Exposition, November 12-18, 2010, Vancouver, British Columbia, Canada, IMECE2010-37042.
[6] Zarrabi K., J.J., 2010, Integrity assesment of notched bars subjected to elastic-plastic-creep damage employing multiaxial stress/strain fields, International Journal of Materials Engineering and Technology 3(2): 173-187.
[7] Robinson E.L., 1952, Effect of Temperature Variation on the Long-Time Rupture Strength of Steels, ASME, 74: 777-780.
[8] Viswanathan R., 1989, Damage Mechanisms and Life Assessment of High Temperature Components, ASM International, Metals Park, OH, 447.
[9] Stigh U., 2006, Continuum Damage Mechanics and the Life-Fraction Rule, ASME Journal of Applied Mechanics 73(4): 702-704.
[10] Webster G.A., Holdsworth S.R., Loveday M.S., Nikbin K., Perrin I.J., Purper H., Skelton R.P., Spindler M.W, 2004, A code of practice for conducting notched bar creep tests and for interpreting the data, Fatigue and Fracture of Engineering Materials and Structures 27(4): 319-342.
[11] Spence J.T.B.A.J.,1983, Stress Analysis for Creep, Butterworths, London 119.
[12] Zarrabi K., 1993, Estimation of boiler tube life in presence of corrosion and erosion processes, International Journal of Pressure Vessels and Piping 53(2): 351-358.
[13] A., S., 2003, Creep and high temperature failure, in: Comprehensive Structural Integrity 5, Elsevier, Pergamon,UK.
[14] Kachanov L.,1958, Time of the Rupture Process Under Creep Conditions, Izv. AN SSSR, Otd. Tekhn, Nauk.
[15] N., R.Y., Proceedings of XII IUTAM Congress, Stamford, CN, edited by Hetenyi and Vincenti, Springer, 1969, 137.
[16] Penny R.K., Marriott D.L., 1995, Design for Creep, Chapman and Hall,London, UK.
[17] Cane B.J., Williams J.A., 1987, Remaining life prediction of high temperature materials, International Materials Reviews 32: 241-264.
[18] Shammas M.S., 1987, Estimating the Remaining Life of Boiler Pressure Parts, EPRI Final Report on RP2253-1,4, Electric Power Research Institute, Palo Alto, CA.
[19] Cane, B.J., Shammas, M.S.,1984, A Method for Remanent Life Estimation by Quantitative Assessment of Creep Cavitation on PLant, Report TPRD/L/2645/N84, Central Electricity Generating Board, Leatherhead.
[20] Elllis F.V., Henry J.F., Shammas M.S., 1989, Remaining Life Estimation of Boiler Pressure Parts,4,Metallographic Models for Weld Heat Affected Zone, EPRI Report CS-5588, Electric Power Research Institue, Palo, Alto,CA, USA.
[21] Hayhurst D.R.L., F A.,1983, Behaviour of materials at high temperatures. Mechanical behaviour of materials - IV; Proceedings of the Fourth International Conference, Stockholm, Sweden;, 15-19 Aug, 1195-1211, UK.
[22] Brown S.G.R., Evans R.W., Wilshire B., 1986, A comparison of extrapolation techniques for long-term creep strain and creep life prediction based on equations designed to represent creep curve shape, International Journal of Pressure Vessels and Piping 24(3): 251-268.
[23] Brown S.G.R., Evans R.W., Wilshire B., 1986, Creep strain and creep life prediction for the cast nickel-based superalloy IN-100, Materials Science and Engineering 84: 147-156.
[24] Dyson B., 2000, Use of CDM in Materials Modeling and Component Creep Life Prediction, Journal of Pressure Vessel Technology 122(3): 281-296.
[25] McLean M., Dyson B.F., 2000, Modeling the Effects of Damage and Microstructural Evolution on the Creep Behavior of Engineering Alloys, Journal of Engineering Materials and Technology 122(3): 273-278.
[26] Budden P.J., 1998, Analysis of the Type IV creep failures of three welded ferritic pressure vessels, International Journal of Pressure Vessels and Piping 75(6): 509-519.
[27] Abe F., W.B., Doi H., Hald J., Holdsworth S.R., Igarashi M., Kern T.-U., Kihara S., Kimura K., Kremser T., Lizundia A., Maile K., Masuyama F., Merckling G., Minami Y., Morris P.F., Muraki J.O. T., Sandstrom R., Schubert J., Schwass G., Spindler M., Tabuchi M., Yagi K., Yamada M., 2004, Creep Properties of Heat Resistant Steels and Superalloys, in: Numerical Data and Functional Relationships in Science and Technology, Group VIII: Advanced Materials and Technologies, Subvolume B, 2,Springer-Verlag Berlin, Heidelberg, New York.
[28] High Temperature Design Data for Ferritic Pressure Vessel, 1983, Mechanical Engineering Publications, Institution of Mechanical Engineers (Great Britain), Creep of Steels Working Party.
[29] Charles B., 2009, IV Process Piping: The Complete Guide to ASME B31.3, Third Edition,ASME, USA.
[30] Tu S.-T., Segle P., Gong J.-M., 1996, Strength design and life assessment of welded structures subjected to high temperature creep, International Journal of Pressure Vessels and Piping 66(1-3): 171-186.
[31] Zarrabi K., Ng L., 2008, A Novel and simple approach for predicting creep life based on tertiary creep behavior, Journal of Pressure Vessel Technology 130(4): 041201.
[32] Zarrabi K., N.L., 2007, An energy based paradigm for predicting creep life based on tertiary creep behavior, The International Journal of Science and Technology -Scientia Iranica - Transactions on : Mechanical and Civil Engineering 14:450-457.
[33] Zarrabi K, H.-T.H., 1997, An innovative robust method for creep life assessments of components containing stress concentrators under primary plus secondary creep, in: Proceedings of the International Joint Power Generation Conference and Exposition, edited by A. Sanyal, A. Gupta and J. Veilleuxn, 2-5 November, EC-Vol.5, ASME, Denver, USA.
[34] Zarrabi K., Hosseini-Toudeshky H., 1995, Creep life assessments of defect-free components under uniform load and temperature, International Journal of Pressure Vessels and Piping 62(2): 195-200.
[35] Brown R.J., B.J.C., Walters D.J., 1981, Creep Failure analysis of butt welded tubes, Proceedings of the 1st International Conference on Creep and Fracture of Engineering Materials and Structures, Swansea, Pineridge Press, 645-659.
[36] ANSYS, ANSYS Release 12.0, ANSYS, Inc., MAY-2008, USA.
[37] Wilshire B., Scharning P.J., 2008, Extrapolation of creep life data for 1Cr-0.5Mo steel, International Journal of Pressure Vessels and Piping 85(10): 739-743.