Optimization of Local Laser Heat Treatment Process Using a Simple FE-Model

Abstract:

Local laser heat treatment is an efficient method to manufacture tailored heat-treated steel strips. It can be applied to soften narrow zones of the strip in order to improve its formability on desired areas. However, the properties achieved are dependent on several process parameters. An objective is to develop a predictive model to optimize the heat treatment parameters instead of using experimental trials. In the present study, a finite element model was applied to predict the maximum temperature and heating and cooling rates, as well as the heat distribution along the heat treated area. To develop the model and to test its feasibility, experiments were performed, in which process parameters were varied to study their effects on temperature distribution in a 6 mm thick abrasion resistant steel grade. Scanning of a laser beam was used to optimize the width and depth of the heat-affected zone.In practice, local laser heat treatment process parameters have to be optimized with care for successful results. The most important task is to minimize the temperature gradient between the surfaces and to keep the peak temperatures close to the austenitizing temperature. The results indicate that a simple model can be used to predict the outcome of the heat treatment, so that finite element modeling can be adopted as a suitable tool for design of local heat treatments, allowing more advanced treatments and applications with complex geometries.

• Periodical: Materials Science Forum (Volume 762)
• Pages: 360-367
• DOI: https://doi.org/10.4028/www.scientific.net/MSF.762.360
• Online since: July 2013
• Authors: Antti Järvenpää, T. Kiuru, Antti Määttä, Matias Jaskari, Kari Mäntyjärvi
• Keywords: Formability, Grain Refinement, Inverse Approach, Laser Heat Treatment, Strength

References

[1] A. Järvenpää, K. Mäntyjärvi, M. Merklein, A. Määttä, M. Hietala, J. Karjalainen: Menary, G. (Ed.): The 14th International ESAFORM Conf. on Material Forming, 1353(2011), AIP Conference Proceedings, pp.1319-1324

[2] Information on http://www.ssab.com/en/Products--Services/Products--Solutions/Products/Hardox/Hardox-600/

[3] A. Järvenpää, P. Karjalainen, and M. Jaskari: XVI International Colloquium "Mechanical Fatigue of Metals" Conf. Brno, Czech Republic (2012)

[4] K. Mäntyjärvi, J.A. Karjalainen, A. Järvenpää, J. Ojala, M. Keskitalo, J. Mäkikangas: Proceedings of the 12th NOLAMP Conf. in Laser Processing of Materials, Copenhagen, Denmark (2009)

[5] A. Järvenpää, M. Jaskari, L.P. Karjalainen, M. Hietala: The 16th International ESAFORM Conference on Material Forming, Aveiro, Portugal (2013)

[6] A-M. Arola, K. Mäntyjärvi, J.A. Karjalainen: SHEMET13 International Conference on Sheet Metal, Belfast, Irland (2013)

[7] Information on www.dynaexamples.com/

[8] Standard EN 1993-1-2, Eurocode 3: Design of steel structures - Part 1-2: General rules - Structural fire design, CEN, 2005.

DOI: 10.1002/9783433601570.oth1

[9] A.B. Shapiro: Heat Transfer in LS-DYNA, 4th European LS-DYNA users conference. (2003) http://www.dynalook.com/european-conf-2003/heat-transfer-in-ls-dyna.pdf

DOI: 10.1299/jsmefed.2003.12

[10] T. Kleeh, M. Merklein and K. Roll: Key Eng. Mater. Vol. 473 (2011), pp.501-508

[11] J. Goldak, A. Chakravarti and M. Bibby: Metall. Trans. B Vol. 15B (1984), pp.299-305

[12] Information on http: //www.engineeringtoolbox.com/overall-heat-transfer-coefficients-d_284.html

[13] Information on http://www.engineeringtoolbox.com/convective-heat-transfer-d_430.html]

[14] C. Lesch, P. Alvarez, W. Bleck, J. G. Sevillano: Metall. and mat. Trans. Vol. 38A (2007), pp.1882-1890.

[15] M. Ferry, D. Muljono, D. P. Dunne: Vol. 41 (2001), p.1053–1060.

[16] M. Steen William: Laser Mater. Processing, 3rd edition, Springer, London (2003)

[17] J. Talonen, P. Nenonen, G. Pape and H. Hänninen: Metall. Mater. Trans. A Vol. 36A (2005), pp.421-432