A Test for Evaluating the Effects of Stress-States on Damage Evolution with Specific Application to the Hot Rolling of Free-Cutting Steels

Abstract

A new conical splay test is developed to assess the mechanisms of damage evolution in a range of stress states representative of hot rolling. The test consists of a bulk forming operation between open dies, during which plastic deformation occurs across a gradient of stress states from near-uniaxial tension to highly compressive. The transition between tensile and compressive stress state allows the microstructure to be accurately linked to the corresponding stress state. FE simulation of the new test is used to analyze the stress-state history during deformation. A low-carbon free-cutting steel, which is prone to edge cracking during hot rolling, is studied and the modes of damage evolution are discussed.

Keywords

hot forming hot rolling damage stress-state effects materials modeling.

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References

Baker, T.J. and Charles, J.A. ( 1972). Deformation of MnS Inclusions in Steel, Journal of the Iron and Steel Institute, 210: 680-690.

Bayoumi, L.S. and Lee, Y. ( 2004). Effect of Interstand Tension on Roll Load, Torque and Workpiece Deformation in the Rod Rolling Process, Journal of Materials Processing Technology, 145: 7-13.

Bielski, J. ( 2006). Implementation of a Model of Coupled Elastic-plastic Unilateral Damage Material to Finite Element Code, International Journal of Damage Mechanics, 15: 5-39.

Clift, S.E. , Hartley, P. et al. (1990). Fracture Prediction in Plastic Deformation Processes, International Journal of Mechanical Sciences, 32: 1-17.

Cusminsky, G. and Ellis, F. ( 1967). An Investigation into the Influence of Edge Shape on Cracking During Rolling, Journal of the Institute of Metals , 95: 33-37.

Dodd, B. and Boddington, P. ( 1980). The Causes of Edge Cracking in Cold Rolling, Journal of Mechanical Working Technology, 3: 239-252.

Dorgan, R. ( 2006). A Mixed Finite Element Implementation of a Gradient-enhanced Coupled Damage-plasticity Model, International Journal of Damage Mechanics, 15(3): 201-235.

Farrugia, D.C.J. ( 2006). Prediction and Avoidance of High Temperature Damage in Long Product Hot Rolling, Journal of Materials Processing Technology.

Foster, A.D. , Lin, J. , Farrugia, D.C.J. and Dean, T.A. ( 2007). Investigation into Damage Nucleation and Growth for a Free-cutting Steel under Hot-rolling Conditions, Journal of Strain Analysis, 42(Special Issue): 1-9.

10.

Gouveia, B.P.P.A. , Rodriguez, J.M.C. and Martins, P.A.F. ( 1996). Fracture Predicting in Bulk Metal Forming, International Journal of Mechanical Sciences, 38: 361-372.

11.

Han, M.H. , Lee, S. , Kim, N.J. , Lee, K.J. , Chung, T. and Byun, G. ( 1999). Analysis and Prevention of Edge Cracking Phenomenon during Hot Rolling of Non-oriented Electrical Steel Sheets, Materials Science and Engineering A, 264: 47-59.

12.

Hayhurst, D.R. ( 1972). Creep Rupture under Multi-axial States of Stress , Journal of the Mechanics and Physics of Solids, 20: 381-390.

13.

Hayhurst, D.R. , Leckie, F.A. and Morrison, C.J. ( 1978). Creep Rupture of Notched Bars, Proceedings of the Royal Society of London. Series A, 360: 243-264.

14.

Hayhurst, D.R. and Leckie, F.A. ( 1977). Design of Notched Bars for Creep-rupture Testing under Tri-axial Stresses, International Journal of Mechanical Sciences , 19: 147-159.

15.

Hayhurst, D.R. , Lin, J. and Hayhurst, R.J. ( 2008). Failure in Notched Tension Bars due to High-temperature Creep: Interaction between Nucleation Controlled Cavity Growth and Continuum Cavity Growth, International Journal of Solids and Structures , 45: 2233-2250.

16.

Lin, J. , Foster, A.D. and Dean, T.A. ( 2007). On Micro-damage in Hot Metal Working Part 2: Constitutive Modelling, Engineering Transactions, 55: 1-18.

17.

Lin, J. , Kowalewski, Z.L. and Cao, J. ( 2005). Creep Rupture of Copper and Aluminium Alloy under Combined Loadings-experiments and their Various Descriptions, International Journal of Mechanical Sciences, 47: 1038-1058.

18.

Liu, Y. , Foster, A.D. , Lin, J. , Farrugia, D.C.J. and Dean, T.A. ( 2006). On Micro-damage in Hot Metal Working Part 1: Experimental investigation, Engineering Transactions, 54: 271-287.

19.

Nicholson, A. and Murray, J.D. ( 1965). Surface Hot Shortness in Low-carbon Steel, Journal of the Iron and Steel Institute, 203: 1007-1018.

20.

Nicholson, A. , Smith, D. and Shaw, P. ( 1968). Hot Workability Testing at United Steel Companies , ISI Publication, 108: 161-167.

21.

Ochoa, J. , Lopez, B. and Rodriguez-lbaba, J.M. ( 2002a). Hot Workability of Sulphur Containing Free-cutting Steels, Thermomechanical Processing: Mechanics, Microstructure & Control, The University of Sheffield, England.

22.

Ochoa, J. , Lopez, B. and Rodriguez-lbaba, J.M. ( 2002b). Effects of Matrix/MnS Particle Interaction on Hot Workability of S Free-cutting Steels. In: 44th Mechanical Working and Steel Processing Conference Proceedings, Orlando, Florida .

23.

Schey, J.A. ( 1966). Prevention of Edge Cracking in Rolling by Means of Edge Restraint, Journal of the Institute of Metals, 94: 193-200.

24.

Siebel, E. and Pomp, A. ( 1927). Die Ermittlung der Formanderungsfestigkeit von Metallen durch den Stauchversuch, Mitt. K.-Wilhelm-Inst. Eisenforsch , 9: 157-169.

25.

Tarnovskii, I.Y. , Pozdeyev, A.A. and Lyashkov, V.B. ( 1965). Deformation of Metals during Rolling, Oxford, Pergamon Press Ltd.

26.

Teirlinck, D. , Zok, F. , Embury, J.D. and Ashby, M.F. ( 1988). Fracture Mechanism Maps in Stress Space, Acta Metallurgica, 36: 1213-1228.

27.

Thomson, P.F. and Burman, N.M. ( 1980). Edge Cracking in Hot-rolled Al-Mg Alloys, Materials Science and Engineering, 45: 95-107.

28.

Wallin, M. ( 2008). Modeling of the Degradation of Elastic Properties due to the Evolution of Ductile Damage, International Journal of Damage Mechanics, 17: 149-172.

29.

Yoshizawa, M. and Ohsawa, H. ( 1997). Evaluation of Strain-rate Sensitivity in Superplastic Compressive Deformation, Journal of Materials Processing Technology , 68: 206-214.