Effect of Austempering Time and Temperature on the Microstructure and Hardness of Bainitic Silicon Steel

Document Type : Original Research Article

Authors

1 Professor, School of Metallurgy and Materials Engineering, Iran University of Science and Technology

2 M.Sc. Student, School of Metallurgy and Materials Engineering, Iran University of Science and Technology

10.22034/frj.2018.106311.1010

Abstract

In this research, the effect of austempering heat treatment time and temperature on the mechanical properties and microstructure of high silicon steel were investigated. The melting process of this alloy was carried out in an induction furnace with the capacity of 20 kg followed by casting in a Y-block mold cavity. After cutting, the samples were austenitized for 2 hours at 1150ºC and austempered at 250 and 300ºC temperatures for 2 to 72 hours. The achieved microstructure showed nanometer layers of bainitic-ferrite, and retained-austenite between them. Increasing the austempering time led to the increment of the amount of bainitic-ferrite. The amount of bainitic-ferrite in samples, austempered at 250ºC, was 84% and in the maximum state was about 91%. A maximum hardness value of 611 HV was obtained in samples austempered at 250ºC for 72 hours.

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References

[1] Caballero F., Miller M.K., Garcia-Mateo C., Capdevila C., De Andrés C.G., Phase transformation theory: a powerful tool for the design of advanced steels, Journal of Metals, 2008, 60(12) 16-21.
[2]  Hanzaki A.Z., PD H., Yue S., The influence of bainite on retained austenite characteristics in Si-Mn TRIP steels, ISIJ international, 1995, 35(1) 79-85.
[3]  Sugimoto K.I., Usui N., Kobayashi M., Hashimoto S.I., Effects of volume fraction and stability of retained austenite on ductility of TRIP-aided dual-phase steels, ISIJ international, 1992, 32(12) 1311-1318.
[4] Qian L., Zhou Q., Zhang F., Meng J., Zhang M., Tian Y., Microstructure and mechanical properties of a low carbon carbide-free bainitic steel co-alloyed with Al and Si, Materials & Design, 2012, 39, 264-268.
[5] Caballero F.G., Miller M.K., Babu S.S., Garcia-Mateo C., Atomic scale observations of bainite transformation in a high carbon high silicon steel, Acta Materialia, 2007, 55(1) 381-390.
[6] Soliman M., Palkowski H., Ultra-fine bainite structure in hypo-eutectoid steels, ISIJ international, 2007, 47(12) 1703-1710.
[7]  گلعذار م.، اصول و کاربرد عملیات حرارتی فولادها, انتشارات دانشگاه صنعتی اصفهان، چاپ دوم، 1379.
[8] Bhadeshia H.K.D.H., Christian J., Bainite in steels, Metallurgical transactions A, 1990, 21(3) 767-797,.
[9] Bhadeshia H.K.D.H., Garcia-Mateo C., Brown P., Bainite steel and methods of manufacture thereof, ed: Google Patents, 2015.
[10] Porter D.A., Easterling K.E., Sherif M., Phase Transformations in Metals and Alloys, (Revised Reprint), CRC press, 2009.
[11] Caballero F., Garcia-Mateo C., The Processing of Nanocrystalline Steels by Solid Reaction, Chapter 4 in Nanostructured Metals and Alloys, Woodhead Publishing Series in Metals and Surface, 2011, 85-117.
[12]https://www.phasetrans.msm.cam.ac.uk/map/steel/programs/mucg83.html
 [13] ASM Handbook "Properties and Selection: Irons, Steels, and High-performance Alloys", ASM International, 2001.
[14] Matsuda H., Bhadeshia H.K., Kinetics of the bainite transformation, in Proceedings of the Royal Society of London A: Mathematical, Physical and Engineering Sciences, 2004, 460(2046) 1707-1722:
[15] Singh S., Bhadeshia H., Estimation of bainite plate-thickness in low-alloy steels, Materials Science and Engineering: A, 1998, 245(1) 72-79.
[16] Garcia-Mateo C., Caballero F.G., Bhadeshia H.K.D.H.,, Development of hard bainite, ISIJ international, 2003, 43(8) 1238-1243.
[17] Garcia-Mateo C., Caballero F.G., Sourmail T., Kuntz M., Cornide J., Smanio V., Elvira R., Tensile behaviour of a nanocrystalline bainitic steel containing 3wt% silicon, Materials Science and Engineering: A, 2012, 549, 185-192.
[18] Garcia-Mateo C., Caballero F.G., Bhadeshia H.K.D.H., Acceleration of low-temperature bainite, ISIJ international, 2003, 43(11) 1821-1825.
Founding Research Journal
Volume 1, Issue 2 - Serial Number 2
December 2017
Pages 79-87

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History

  • Receive Date: 20 November 2017
  • Revise Date: 11 March 2018
  • Accept Date: 21 January 2018

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