فراوری فولاد ساده کربنی فوق ریز دانه از طریق دگرگونی دینامیکی تحت کرنش آستنیت به فریت در حین تغییر شکل با روش تلفیقی اکستروژن- پرس

نویسندگان

1 1- دانشکده فنی، دانشگاه مراغه

2 2- دانشگاه فنی و حرفه‌ای، آموزشکده شماره 2 تبریز

3 3- باشگاه پژوهشگران جوان و نخبگان، دانشگاه آزاداسلامی، واحد ایلخچی

چکیده

در پژوهش حاضر، یک نوع فولاد ساده کربنی با ساختار فوق ریز دانه با اعمال یک فرایند ترمومکانیکی موثر در گستره دمایی آستنیت شبه پایدار (Ae3-Ar3) و با استفاده از روش تلفیقی اکستروژن - پرس در کانال‌های زاویه ­دار با مقاطع همسان فراوری شد. در ابتدا با استفاده از تحلیل المان محدود سه بعدی دما - جابه‌جایی، تاثیر دمای پیشگرم در توزیع کرنش و دما در نمونه‌های تغییر شکل داده شده مورد بررسی قرار گرفت. با استفاده از نتایج به‌دست آمده، دمای 930 درجه سانتی‌گراد به‌عنوان مناسب‌ترین دمای پیشگرم برای دستیابی به ساختار فوق ریز دانه از طریق وقوع دگرگونی دینامیکی آستنیت به فریت انتخاب شد. با اعمال تغییر شکل بر روی فولاد مورد نظر در این دمای پیشگرم و بررسی ریزساختار نهایی، نتایج حاصل از تحلیل المان محدود مورد تایید قرار گرفت. نتایج نشان داد که در اثر این فرایند ترمو‌مکانیکی اندازه دانه‌های فریت از 32 میکرومتر در ساختار اولیه به 1 تا 3 میکرومتر پس از اعمال فرایند کاهش پیدا می‌کند.

کلیدواژه‌ها


عنوان مقاله [English]

Fabrication of Ultra-Fine Grained Plain Low Carbon Steel through Dynamic Strain Induced Transformation during Integrated Extrusion Equal Channel Angular Pressing

نویسندگان [English]

  • H. Shokrvash 1
  • A. Vajd 2
  • M. Shaban Ghazani 3
1 1- Faculty of Engineering, University of Maragheh, Maragheh, Iran.
2 2- Technical College of Tabriz No.2, Technical and Vocational University, Tabriz, Iran.
3 3- Young Researchers and Elite Club, Islamic Azad University, Ilkhchi branch, Iran
چکیده [English]

In the present research, an effective thermo-mechanical processing route in the temperature range of metastable austenite region (Ae3<T< Ar3) was employed to achieve ultra-fine grain size in a plain low carbon steel during integrated extrusion equal channel angular pressing. At first, the effect of preheating temperature on the strain and temperature distributions inside the deformed samples were investigated using 3D finite element simulation. According to the result of FEM simulation, the preheating temperature of 930 ˚C was selected as an appropriate temperature for fabrication of ultra-fine ferrite structure. Severe plastic deformation was then imposed on samples with the predicted preheating temperature and the results showed a great consistency with FEM simulation predictions. Optical micrographs taken from the center point of the  samples showed that the ferrite grains could be refined from 32 &mu;m to 1-3 &mu;m by different mechanisms.

کلیدواژه‌ها [English]

  • Finite element simulation
  • Severe plastic deformation
  • Ultra-fine grained steel
1. Langdon, T.G., “The Processing of Ultrafine Grained Materials through the Aplication of Severe Plastic Deformation”, Journal of Materials Science,
Vol. 42, pp. 3388–3397, 2007.
2. Lowe, T.C. and Valiev, R.Z., “The Use of Severe Plastic Deformation Techniques in Grain Refinement”, JOM, pp. 64-77, 2004.
3. Nagato, K., Sugiyama, S., Yanagida, A. and Yanagimoto, J, “Single-Pass Severe Plastic Forming of Ultrafine-Grained Plain Carbon Steel”, Materials Science and Engineering A, Vol. 478, pp. 376-383, 2008.
4. Wang, J.T., Xu, C., Du, Z.Z., Qu, G.Z. and Langdon, T.G., “Microstructure and Properties of a Low-Carbon Steel Processed by Equal-Channel Angular Pressing”, Materials Science and Engineering A, Vol. 410–411, pp. 312–315, 2005.
5. Nagarajan, D., Chakkingal, U. and Venugopal, P., “Influence of Cold Extrusion on the Microstructure and Mechanical Properties of an Aluminium Alloy Previously Subjected to Equal Channel Angular Pressing”, Journal of Materials Processesing Technology, Vol. 182, pp. 363–368, 2006.
6. Estrin, Y., Janecek, M., Raab, G.I., Valiev, R.Z. and Zi, A., “Severe Plastic Deformation as a Means of Producing Ultra-Fine-Grained Net-Shaped Micro Electro-Mechanical Systems Parts”, Metals and Materials Transactions A, Vol. 38, pp. 1906-1909, 2007.
7. Iwahashi , Y., Wang, J.T., Horita, Z., Furukawa, M. and Langdon T.G., “Principle of Equal-Channel Angular Pressing for the Processing of Ultra-Fine Grained Materials”, Scripta Materialia, Vol. 35,
pp. 143–146, 1996.
8. Paydar, M.H., Reihanian, M., Bagherpour, E., Sharifzadeh, M., Zarinejad, M. and Dean, T.A., “Consolidation of Al Particles through Forward Extrusion-Equal Channel Angular Pressing (FE-ECAP)”, Materials Letters, Vol. 62, pp. 3266-3268, 2008.
9. Paydar, M.H., Reihanian, M., Bagherpour, E., Sharifzadeh, M., Zarinejad, M. and Dean, T.A., “Equal Channel Angular Pressing–Forward Extrusion (ECAP–FE) Consolidation of Al Particles”, Material and Design, Vol. 30, pp. 429-432, 2009.
10. Orlov, D., Raab, G., Lamark, T.T., Popov M. and Estrin Y., “Improvement of Mechanical Properties of Magnesium Alloy ZK60 by Integrated Extrusion and Equal Channel Angular Pressing”, Acta Materialia, Vol. 59, pp. 375-385, 2011.
11. Stráská, J., Janeček, Mi., Čížek, J., Stráský, J. and Hadzima, B., “Microstructure Stability of Ultra-Fine Grained Magnesium Alloy AZ31 Processed by Extrusion and Equal-Channel Angular Pressing (EX–ECAP)”, Material Characterization, Vol. 94, pp. 69-79, 2014.
12. Wang, S., Liang, W., Wang, Y., Bian, L. and Chen, K., “A Modified Die for Equal Channel Angular Pressing”, Journal of Materials Processing Technology, Vol. 209, pp. 3182-3186, 2009.
13. Fatemi-Varzaneh, S. M., Zarei-Hanzak, A. ,Naderi, M. and Roostaei , A., “Deformation Homogeneity in Accumulative Back Extrusion Processing of AZ31 Magnesium Alloy”, Journal of Alloys and Compounds, Vol. 507, pp. 207-214, , 2010.
14. Djavanroodi, F. and Ebrahimi, M., “Effect of Die Parameters and Material Properties in ECAP with Parallel Channels”, Materials Science and Engineering A, Vol. 527, pp. 7593-7599, 2010.
15. Balasunda, I., Rao, M.S. and Raghu, T., “Equal Channel Angular Pressing Die to Extrude a Variety of Materials”, Materials and Design, Vol. 30,
pp. 1050-1059, 2009.
16. Pei, Q.X., Hu, B.H., Lu, C. and Wang, Y.Y., “A Finite Element Study of the Temperature Rrise during Equal Channel Angular Pressing”, Scripta Materialia, Vol. 49, pp. 303-308, 2003.
17. Palmiere, E.J., Garcia, C.I. and DeArdo, A.J., “The Influence of Niobium Supersaturation in Austenite on the Static Recrystallization Behavior of Low Carbon Microalloyed Steels”, Metallurgical and Materials Transactions A, Vol. 27A, pp. 951-960, 1996.
18. Palmiere, E.J., Garcia, C.I. and De-Ardo, A.J., “Compositional and Microstructural Changes which Attend Reheating and Grain Coarsening in Steels Containing Niobium”, Metallurgical and Materials Transactions A, 1994, 25A, pp. 277-286.
19. Siciliano, F.J. and Jonas, J.J., “Mathematical Modeling of the Hot Strip Rolling of Microalloyed Nb, Multiply-Alloyed Cr-Mo, and Plain C-Mn Steels”, Metallurgical and Materials Transactions A, Vol. 31A, pp. 511-530, 2000.
20. Beladi, H., Kelly, G.L., Shokouhi, A. and Hodgson, P.D., “Effect of Thermomechanical Parameters on the Critical Strain for Ultrafine Ferrite Formation through Hot Torsion Testing”, Materials Science and Engineering A, Vol. 367, pp. 152-161, , 2004.
21. Hickson, M.R., Gibbs, R. K. and Hodson, P.D., “The Effect of Chemistry on the Formation of Ultrafine Ferrite in Steel”, ISIJ International, Vol. 39,
pp. 1176-1180, 1999.
22. Zheng, Ch., Li, D., Lu, Sh. and Li, Y., “On the Ferrite Refinement during the Dynamic Strain-Induced Transformation: A Cellular Automaton Modeling”, Scripta Materialia, Vol. 58, pp. 838–841, 2008.
23. Hong, S.C., Yoon, C.S., Lee, K.J., Shin, D.H. and Lee K.S., Ultrafine Grained Materials ІІІ, pp. 641-646, 2004.
24. H. Beladi, “Ultrafine Ferrite Formation in Steels through Thermomechanical Processing”, PhD Thesis, Deakin University, Australia, 2004.

تحت نظارت وف ایرانی