ABSTRACT The mechanical behaviour of duplex phases produced in a medium carbon low alloy steel with potentials for use as machine body parts and vehicle panels, has been investigated. A representative composition of the steel (C: 0.3; Si: 0.28; Mn: 0.97; Cr: 0.15) was utilized to produce ferrite – martensite duplex phases of varied proportions by intercritical annealing treatment. The tensile, hardness, and rotating bending fatigue behaviour of the structures were studied; and optical and SEM microscopy utilized to characterize the microstructures and their fracture characteristics. The duplex phase structures exhibited continuous yielding behaviour; and were characterised by high strain hardenability, high tensile strength, total elongation, toughness and superior fatigue strength (endurance limit) in comparison with the normalised structure. The fatigue fracture was observed to be characterized by mixed mode of ductile (dimple) fracture and intergranular brittle cleavage for the duplex structures. Superior tensile and fatigue property combinations were better harnessed when treatment was performed at 760℃ and 780℃ in comparison to 740℃.
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K. Alaneme, S. Ranganathan and T. Mojisola, "Mechanical Behaviour of Duplex Phase Structures in a Medium Carbon Low Alloy Steel," Journal of Minerals and Materials Characterization and Engineering, Vol. 9 No. 7, 2010, pp. 621-633. doi: 10.4236/jmmce.2010.97044.
 M. Yano, S. Kitamura, T. I. Harashima, T. Inomoto, K. Azuma, and H. Nagahama, Recent Advances in Ultra low – Carbon Steel Refining Technology by Vacuum Degassing Processes, Nippon Steel Technical Report, No. 61, UDC 669 (1994) 18 – 982.
B. Gajda, A. K. Lis, Intercritical Anealing with Isothermal Holding of Trip CMnAlSi Steel, Journal of Achievements in Materials and Manufacturing, Vol. 20, Issues 1 – 2, 2007, Pp 439 – 442.
J. A. Lozano, and J. T. Panta – Mesones, Evaluation of the Heat-treatment Response of a Multiphase Hot – Rolled Steel Processed by Controlled Rolling and Accelerated Cooling, Materials and manufacturing Processes, 23 (2008) 357 – 362.
I. Nobuyuki, S. Nobuo, and K. Joe, Development of Ultra – High Strength Linepipes with Dual – Phase Microstructure for high Strain Application, JFE Technical Report, No. 12, 2008, Pp 15 – 19.
M. Mazinani, and W. J. Poole, Deformation Behaviour of Martensite in a Low-Carbon Dual – Phase steel, Advanced Materials Research, Vols 15 – 17, (2007), Pp 774 – 779.
S. Sun, and M. Pugh, Properties of Thermomechanically processed Dual – Phase Steels containing fibrous Martensite, Materials Science and Engineering A, Vol. 335, Issues 1 – 2 (2002) Pp 298 – 308.
A. Kumar, S. B. Singh, K. K. Ray, Influence of bainite/Martensite – content on the tensile properties of low carbon dual phase steels, Materials Science and Engineering A, 474 (2008) 270 – 282.
K. Spencer, J. D. Embury, K. T. Colon, M. Veron, Y. Brechet, Strengthening via the formation of strain – induced Martensite in stainless steels, Materials Science and Engineering A, 387 389 (2004) 873 – 881.
A. Bayram, A. Uguz, and M. Ula, Effects of Mechanical properties of Dual – Phase Steels, Materials characterization, 43 (1999) Pp 259 – 269.
H. Xu, W. Yang, and Z. Sun, Mechanical Properties of fine-grained dual phase low – carbon steels based on dynamic transformation, Journal of University of Science and Technology Beijing, Mineral, Metallurgy, materials, Vol. 15, Issue 5 (2008) Pp 556 – 560.
Y. Son, Y. K. Lee, K. T. Park, C. S. Lee, and D. H. Shin, Ultra-fine grained ferrite-martensite dual phase steels fabricated via equal channel angular pressing: microstructure and tensile properties, Acta materialia, Vol. 53, Issue 11 (2005) Pp 3125 – 3134.
R. S. Tripathi, R. S. Rama Rao. and S. P. Pattanaik, High Cycle Fatigue, Crack Propagation Resistance and Fracture Toughness in Ship Steels, Defence Science Journal, Vol. 51, No. 2, 2001 Pp 201 - 210.
N. Rao, and A. R. Acharya, Fracture Behaviour of a High Strength medium Carbon Low Alloy Steel, Engineering Fracture Mechanics, Vol. 53, No.2, 1996 Pp 303 – 308.
A. Bhattacharyya, T. Sakaki, and G. J. Weng, Influence of Martensite Shape, Concentration, and Phase Transformation Strain on the Deformation Behaviour of Stable Dual – Phase Steels, Metallurgical and Materials Transactions A, Vol. 24, No.2, (1993) Pp 301 – 314.
A. A. Gorni, Steel Forming and Heat treating Handbook, Vol. 2, Sao Vacente, Brazil, (2006): Pp 4.
ASTM E 8M – 91: Standard test Method for Tension Testing of Metallic Materials [Metric]. In: Annual Book of ASTM Standards: ASTM International; 1992, Pp 160.
K. Park, C. S. Lee, and D. H. Shin, Strain Hardenability of Ultra fine Grained low Carbon Steels Processed by ECAP, Rev. Adv. Mater. Sci (10) 2005 Pp 133 – 137.
A. R. Salehi, S. Serajzadeh, and A. K. Taheri, A Study on the Microstructural changes in Hot Rolling of Dual – Phase steels, Journal of Materials Science, Vol. 41, No.7, 2006, Pp 1917 – 1925.
M. Tayanc, A. Aytac, and A. Bayram, The effect of carbon on the fatigue strength of dual – phase steels, Materials and Design, Vol. 28, Issue 6 (2007) Pp 1827 1835.
P. C. Chakraborti, M. K. Mitra, International Journal of Fatigue 27 (5) 2005 Pp 511 – 518.
H. J. Hadianfard, Low cycle Fatigue Behaviour and Failure Mechanism of a dual – phase steel, materials Science and Engineering A 499 (2009) Pp 493 – 499.
S. Alzari, J. Morriconi, E. Brandaleze, W. Chiapparoli, G. Mansilla, S. Herenu, Practical Fatigue resistance assessment of microalloyed high strength and dual phase steels, 16th IAS Rolling Conference, 2006, San Nicolas, Argentina, Pp 683 -690.
K. Nakajima, T. Urabe, Y. hosoya, S. Kamiishi, T. Miyata and N. Takeda, Influence of microstructural morphology and prestraining on short fatigue crack propagation in dual phase steels, ISIJ International, Vol. 41 (2001), No.3, Pp 298 – 304.
T. Alp, and A. Wazzan, The Influence of microstructure on the tensile and fatigue behaviour of SAE 6150 Steel, Journal of Materials Engineering and Performance, Vol. 11, Issue 4, Pp 351 – 359. DOI: 10.1361/105994902770343854.
K. V. Sudhakar, and E. S. Dwarakadasa, A study on fatgue crack growth in dual phase martensitic steel in air environment, Bull. Mater. Sci., Indian Academy of Sciences, Vol. 23, No. 3, Pp 193 - 199.