On the Effect of γ-phase transformation kinetics upon microstructure response of Cold Heading Quality Steel
Keywords:CHQ steel, Up-quenching, Phase transformation, microstructure, heating rate, austenite etc
Cold heading quality CHQ steel is a versatile form over other steels as they are used non-heat treated; their strengthening mechanism is achieved through cold heading operations. Metal is therefore stretched without applying any source of heat, metal flow during the cold heading operation must depend on grains flow which increases the mechanical properties such as strength, resistance to indentation and toughness. It is therefore necessary to form the isotropic grains before applying cold heading operation may increase the properties. Gamma phase formation during the heat treatment is crucial factor for cold operation. An effort is made in this research work to study and find out the Austenite nucleation and growth morphology of commercial CHQ steel through continuous heating experiments by utilizing lead-bath up-quenching technique at different
austenizing temperature ranges. High class Optical Microscope Olympus GX51, scanning electron microscopy techniques have been utilized to reveal and interpret the microstructure and it was found that At the 740°C, the microstructure shows the lack of homogeneity in the structure hence cold-head-ability of CHQ steel is anisotropic but at the high temperature in austenite domain at 60sec the resultant austenite is highly homogenous due to high volume fraction of austenite has been formed then the cold-head-ability properties of CHQ steel turned to be isotropic.
T. Das, "Evaluation of two AISI 4037 cold heading quality steel wires for improved tool life and product quality" Materials Engineering and Performance, vol. 11: 1, 2002, pp. 86-91.
Xiaoyu MA "Effect of Microstructure on the Cold Headability of a Medium Carbon Steel". ISIJ International, vol. 44:5, 2004, pp. 905-913.
J. Huang. "Austenite formation during intercriticalannealing”Met and Mat trans A, vol. 35:11, 2004, pp 3363-3375.
R. Hill: “Annealing: The First Step in Cold Forming,” Wire J. Int., 2005, 17(7), pp. 95–97.
A. Sabih, “Internal ductile failure mechanisms in steel cold heading process” ISIJ International, vol. 45:8, 2005, pp.1179.
Savran, “Microstructural features of austenite formation in C35 and C45 alloys” Materials Transactions A, vol. 38. 2007, pp. 946.
Jari Rämö”Influence of strain rate and adiabatic heating on the deformation behavior of cold heading steels” Materials Processing Technology. Vol. 209:11, 2009, pp 5186-5194.
J. R. Davis, et al., “Annealing of steel,” Heat treating, vol. 4, ASM International, 2011.
Metallographic Methods for Revealing the Multiphase Microstructure of TRIP-Assisted Steels.
R.L Higginson, C.M Sellars Worked Examples in Quantitative Metallography.
J.W. Christian “Theory of Transformations in Metals and Alloys”.2012.
A. Sabiha “Internal ductile failure mechanisms in steel cold heading process” Mat Sci vol. 6, 2013. Pp.46
Seawoong “stability of ultrafine-grained transformation induced plasticity steel with Mn partitioning”. ISISJ International, vol. 65. 2013, pp. 634-640
H. K. D. H. Bhadeshia. “Mechanical stabilisation of austenite” Materials Science and Technology, vol. 22, 2013, pp.641.
Xueda Li “Influence of prior austenite grain size on martensite–austenite constituent and toughness in the heat affected zone of 700MPa high strength linepipe steel” vol. 616, 2014, pp.141-147.
C. Goulas “Microstructure, texture and mechanical properties in a low carbon steel after ultrafast heating”MatSci and Eng. A. vol.672, 2016, pp.108-120.
F.M.Castro Cerda “Austenite formation in 0.2% C and 0.45% C steels under conventional and ultrafast heating” Materials and Design vol. 116, 2017, pp. 448.
AnishKarmakar “Effect of composition and isothermal holding temperature on the precipitation hardening in Vanadium-microalloyed steels”. Materials Characterization, vol. 132, 2017, pp. 31-40.
Shahid Hussain Abro, “Effect of Heating Rate on Microstructural Developments in Cold Heading Quality Steel used for Automotive Applications” Mehran University Research Journal of Engineering & Technology Vol. 37, 2018, pp.461-466.
Bo Wang “Precipitation Behavior of VN in High Nitrogen and Vanadium Micro-alloyed Low Carbon Weathering Steel” Transactions of the Indian Institute of Metals. Vol. 71:70, 2018, pp. 1607.