Thermal Diffusivity of Traditional and Innovative Sheet Steels

Article Preview

Abstract:

The low carbon steels, used for the production of car bodies by deep drawing, are gradually substituted by high strength steels for vehicle weight reduction. The drawn car body components are joined by welding and the welded points undergo a reduction of the local tensile strength. In developing an accurate welding process model, able to optimized process parameters and to predict the final local microstructure, a significant improvement can be given by the knowledge of the welded steels thermal diffusivity at different temperatures. The laser-flash method has been used to compare the thermal diffusivity of two traditional deep drawing steels, two high strength steels already in common usage, i.e. a Dual Phase (DP) steel and a TRansformation Induced Plasticity (TRIP) steel, and one experimental high-Mn austenitic TWIP (Twinning Induced Plasticity) steel. The low carbon steels, at low temperatures, have a thermal diffusivity that is 4-5 times larger than the TWIP steel. Their thermal diffusivity decreases by increasing temperature while the TWIP steel shows an opposite behaviour, albeit with a lesser slope, so that above 700°C the TWIP thermal diffusivity is larger. The different behaviour of the TWIP steel in respect to the ferritic deep drawing steels arises from its non ferro-magnetic austenitic structure. The DP and TRIP steels show intermediate values, their diffusivity being lower than that of the traditional deep drawing steels; this latter fact probably arises from their higher alloy content and more complex microstructure.

You might also be interested in these eBooks

Info:

Periodical:

Defect and Diffusion Forum (Volumes 297-301)

Pages:

893-898

Citation:

Online since:

April 2010

Export:

Price:

Permissions CCC:

Permissions PLS:

Сopyright:

© 2010 Trans Tech Publications Ltd. All Rights Reserved

Share:

Citation:

[1] A. DiMatteo, G. Lovicu, M. Desanctis, R. Valentini and A. Solina: Metall. Ital. Vol. 98 (2006), p.37.

Google Scholar

[2] G. Scavino, F. D'Aiuto, P. Matteis, P. Russo Spena and D. Firrao: Proc. EPD Symp. (TMS Ann. Meet., San Francisco, USA, 2009), TMS: Warrendale, USA, 2009, p.111.

Google Scholar

[3] S.C. Hong and K.S. Lee: Mater Sci. Eng. A Vol. 323, (2002), p.148.

Google Scholar

[4] N. Tsuchida, E. Baba, K. Nagai and Y. Tomota: Acta Mater. 53 (2005), p.265.

Google Scholar

[5] S. Maggi. and G. Scavino: Proc. 11th Int. Conf. Fracture, Torino, Italy, 2005, p.522.

Google Scholar

[6] P. Matteis, E. Campagnoli, D. Firrao and G. Ruscica: Int. J. Thermal Sci. Vol. 47 (2008), p.695.

Google Scholar

[7] E. Campagnoli, D. Firrao, P. Matteis, G.M.M. Mortarino, M. Pavese, G. Ruscica, R. Gerosa, B. Rivolta and G. Silva: Proc. 31° Conv. Naz. AIM, Milano, Italy, 2006, p.1.

Google Scholar

[8] S. Saritas: Metal Powder Report Vol. 58 (2003), p.36.

Google Scholar

[9] G. Taher, S. Ben and N. Yacoubi: Tribology Int. Vol. 42 (2009), p.391.

Google Scholar

[10] C. Hamilton, S. Dymec and A. Sommers: Int. J. Mach. Tool. Manu. Vol. 48 (2008), p.1120.

Google Scholar

[11] A.E. Ozgur, B. Yalcin and M. Koru: Mater. Design 30 (2009), p.414.

Google Scholar

[12] K.M. Boubaker, M. Bouhafs and N. Yacoubi: NDT&E Int. 36 (2003), p.547.

Google Scholar

[13] W.J. Parker, R.J. Jenkins, C.P. Butler and G.L. Abbot: J. Appl. Phys. Vol. 32 (1961), p.1679.

Google Scholar

[14] D. Firrao; P. Matteis; G.M.M. Mortarino and G. Scavino, Proc. 22° Conv. Naz. Trattamenti Termici, Salsomaggiore, Italy, 2009, paper n. 35.

Google Scholar

[15] Y.S. Touloukian, R.W. Powell, C.Y. Ho, and M.C. Nicolau: Thermophysical Propertis of Matter Vol. 10, IF/PLENUM, New York (1973), p.82.

Google Scholar

[16] A. Rudajevova and J. Burianel: J. Phase Equilibria Vol. 22 (2001), p.560.

Google Scholar

[17] R.H. Bogaard, P.D. Desai, H.H. Li and C.Y. Ho: Thermochim. Acta Vol. 218 (1993), p.373.

Google Scholar

[18] S. Rudtsch, H.P. Ebert, F. Hemberger, G. Barth, R. Brandt, U. Gross, W. Hohenauer, K. Jaenicke-Roessler, E. Kaschnitz, E. Pfaff, W. Possnecker, G. Pottlacher, M. Rhode and B. Wilthan: Int. J. Thermophys. Vol. 26 (2005), p.855.

DOI: 10.1007/s10765-005-5582-6

Google Scholar

[19] J. Clark and R. Tye: High Temp. High Press. Vol. 35/36 (2003/2004), p.1.

Google Scholar

[20] H.J. Solter: High Temp. High Press. Vol. 19 (1987), p.455.

Google Scholar