Controlled Cooling of Hot Rolled Steel Channels by Water Spraying on the Final Cooling Bed

Srinivas  Rachamadagu; Malur  Srinivasan

doi:10.4236/mme.2014.41004

Srinivas Rachamadagu, Malur Srinivasan

Abstract: The objective of this research is to design an effective and relatively simple method for controlled cooling of hot rolled steel channels by water spraying on the final cooling bed after continuous cast steel billets passing through reheating furnace and sequential rolls to form channels. The need for this research arose as the channels were being cooled by forced air draft and natural convection which brought the temperature of the channels to about 270°C (518°F) at the shear stand. Steel at this temperature is too hot for convenient handling by the operators. Additional cooling by water spraying would be an acceptable solution but such cooling should be designed to enable an acceptable microstructure to be developed in the channel, as the microstructure of steel is strongly affected by nonequilibrium cooling through the eutectoid range: the mechanical properties of steel are a consequence of the microstructure. The approach followed in this investigation was first to develop a finite element method (FEM) to determine the temperature profiles in the channel subjected to cooling by water spraying and natural convection and arrive at suitable water spray rates to bring the temperature of the channel at the shear stand to levels suitable for convenient handling. PATRAN was used for preprocessing and ABAQUS for processing and post processing. Next, laboratory experiments were conducted to determine the microstructure and hardness of channels at the spray rates found suitable through FEM, to suggest the water spray rate most suitable for providing a temperature convenient for handling and for developing a desirable microstructure.

Keywords: Finite Element Method; Steel Channel; Water Spray Cooling; Microstructure; Nonequilibrium Cooling

Cite this paper: S. Rachamadagu and M. Srinivasan, "Controlled Cooling of Hot Rolled Steel Channels by Water Spraying on the Final Cooling Bed," Modern Mechanical Engineering, Vol. 4 No. 1, 2014, pp. 28-34. doi: 10.4236/mme.2014.41004.

References

[1] S. Rachamadagu, “Controlled Heat Trasfer of Hot Rolled Products on the Cooling Bed,” M.S. Thesis, Texas A&M University, College Station, 1993.

[2] R. J. Golstein, E. M. Sparrow and D. C. Jones, “Transfert Massique par Convection Naturelle Adjacente a des Plaques Horizontales,” International Journal of Heat and Mass Transfer, Vol. 16, 1973, p. 1025.

[3] J. R. Lloyd and W. R. Moran, “Natural Convection Adjacent to Horizontal Surfaces of Various Platforms,” ASME Paper 74-WA/HT-66, 1974.

[4] J. E. Hilliard and J. W. Cahn, “An Evaluation of Procedures in Quantitative Metallography for Volume Fraction Analysis,” Transactions AIME, Vol. 221, 1961, pp. 344352.

[5] E. Schmidt and W. Beckmann, “Das Temperatur und Geschwindigkeitsfeld von Einer Warmeabgebenden Senkreschten platte bei Natralischer Konvektion,” Tech, Mech, Thermodynamick, Vol. 1, 1930, p. 341.

[6] M. Bamberger and B. Prinz, “Determination of Heat Transfer Coefficients during Water Cooling of Metals,” Materials Science and Technology, Vol. 2, No. 4, 1986, pp. 410-415. http://dx.doi.org/10.1179/mst.1986.2.4.410

[7] http://www.dultmeier.com/products/0.811.816/3125

[8] P. G. Shewmon, “Transformations in Metals,” McGrawHill Book Company, New York, 1969, p. 248.