Effects of Mn and Nb on the macro- and microsegregation in high-Mn high-Al TRIP steels

• Autorzy: Grajcar A. , Kalinowska-Ozgowicz E. , Opiela M. , Grzegorczyk B. , Gołombek K.
• Języki publikacji: EN

Abstrakty

EN

Purpose: The aim of the paper is to determine the effects of Mn and Nb on the macro- and microsegregation of new-developed (3-5)Mn 1.5Al TRIP steels in the as-cast state and after hot forging. Design/methodology/approach: To assess possible macro- and microsegregation the chemical composition was investigated in the macro scale by OES and by the use of EDS in microregions. To reveal the macrostructure the ingots were etched by Oberhoffer’s reagent. The chemical composition along a diameter of the ingots was tested as well as in different regions of the plastically deformed flats. Metallographic investigations were carried out using optical (OM) and scanning electron microscopy (SEM). Findings: The Mn and Nb contents have significant effects on the obtained bainitic-martensitic structures and the morphology of retained austenite. The tendency to macrosegregation of Mn and Al between middle and external parts of the as-cast ingots and hot forged flats was detected. The Nb micoalloying results in the overall refinement of obtained microstructures and reduces the identified segregation of Al and Mn. A little microsegregation of these alloying elements between structural constituents was also detected. Research limitations/implications: Further investigations to describe in detail the identified structural constituents and the tendency of alloying elements to segregation in the thermomechanically rolled sheets are in progress. Practical implications: The knowledge of the macro- and microsegregation of Mn and Al in the TRIP steels with a high fraction of retained austenite is of primary importance for the manufacturing paths of these multiphase structure steels. Originality/value: A problem of segregation of Al and Mn in advanced high strength steels with and without Nb microaddition was described and interesting types of bainitic structures were identified.

Słowa kluczowe

EN

metallic alloys; TRIP steel; microsegregation; macrosegregation

PL

stopy metali; stal TRIP; mikrosegregacja; makrosegregacja

• Wydawca: International OCSCO World Press
• Czasopismo: Archives of Materials Science and Engineering
• Rocznik: 2011
• Tom: Vol. 49, nr 1
• Strony: 5--14
• Opis fizyczny: Bibliogr. 23 poz.

Twórcy

autor

Grajcar A.

autor

Kalinowska-Ozgowicz E.

autor

Opiela M.

autor

Grzegorczyk B.

autor

Gołombek K.

• Institute of Engineering Materials and Biomaterials, Silesian University of Technology, ul. Konarskiego 18a, 44-100 Gliwice, Poland,

Bibliografia

• [1] R. Kuziak, R. Kawalla, S. Waengler, Advanced high strength steels for automotive industry, Archives of Civil and Mechanical Engineering 8/2 (2008) 103-117.
• [2] A.K. Lis, B. Gajda, Modelling of the DP and TRIP microstructure in the CMnAlSi automotive steel, Journal of Achievements in Materials and Manufacturing Engineering 15 (2006) 127-134.
• [3] J. Adamczyk, A. Grajcar, Structure and mechanical properties of DP-type and TRIP-type sheets obtained after the thermomechanical processing, Journal of Materials Processing Technology 162-163 (2005) 267-274.
• [4] A. Grajcar, Structural and mechanical behaviour of TRIP steel in hot-working conditions, Journal of Achievements in Materials and Manufacturing Engineering 30/1 (2008) 27-34.
• [5] I.B. Timokhina, P.D. Hodgson, E.V. Pereloma, Effect of deformation schedule on the microstructure and mechanical properties of a thermomechanically processed C-Mn-Si transformation-induced-plasticity steel, Metallurgical and Materials Transactions A 34 (2003) 1599-1609.
• [6] A. Grajcar, Morphological features of retained austenite in thermo-mechanically processed C-Mn-Si-Al-Nb-Ti multi-phase steel, Journal of Achievements in Materials and Manufacturing Engineering 39/1 (2010) 7-18.
• [7] E.M. Bellhouse, A.I.M. Mertens, J.R. McDermid, Development of the surface structure of TRIP steels prior to hot-dip galvanizing, Materials Science and Engineering A 463 (2007) 147-156.
• [8] W. Shi, L. Li, Ch. Yang, R.Y. Fu, L. Wang, P. Wollants, Strain-induced transformation of retained austenite in low-carbon low-silicon TRIP steel containing aluminum and vanadium, Materials Science and Engineering A 429 (2006) 247-251.
• [9] W. Bleck, K. Phiu-On, Microalloying of cold-formable multi phase steel grades, Materials Science Forum 500-501 (2005) 97-112.
• [10] A.J. DeArdo, J.E. Garcia, M. Hua, C.I. Garcia, A new frontier in microalloying. Advanced high strength, coated sheet steels, Materials Science Forum 500-501 (2005) 27-38.
• [11] E. De Moor, P.J. Gibbs, J.G. Speer, D.K. Matlock, Strategies for third-generation advanced high-strength steel development, Iron and Steel Technology 7/11 (2010) 133-144.
• [12] S.J. Kim, Effects of manganese content and heat treatment condition on mechanical properties and microstructure of fine-grained low-carbon TRIP-aided steels, Materials Science Forum 638-642 (2010) 3313-3318.
• [13] M.J. Merwin, Microstructure and properties of cold rolled and annealed low-carbon manganese TRIP steels, Iron and Steel Technology 5/10 (2008) 66-84.
• [14] B. Wietbrock, M. Bambach, S. Seuren, G. Hirt, Homogenization strategy and material characterization of high-manganese TRIP and TWIP steels, Materials Science Forum 638-642 (2010) 3134-3139.
• [15] I. Tsukatani, S. Hashimoto, T. Inoue, Effects of silicon and manganese addition on mechanical properties of high-strength hot-rolled sheet steel containing retained austenite, ISIJ International 31 (1991) 992-1000.
• [16] P.D. Hodgson, I.B. Timokhina, H. Beladi, Structure-property relationship in thermomechanically processed high strength steels containing bainite, Proceedings of the 2nd International Conference "Super-High Strength Steels", Peschiera del Garda, 2010, 1-7 (CD-ROM).
• [17] S. Zajac, V. Schwinn, K.H. Tacke, Characterisation and quantification of complex bainitic microstructures in high and ultra-high strength linepipe steels, Materials Science Forum 500-501 (2005) 387-394.
• [18] I.B. Timokhina, E.V. Pereloma, H. Beladi, P.D. Hodgson, A study of the strengthening mechanism in the thermo-mechanically processed TRIP/TWIP steel, Proceedings of the 3rd International Conference "Thermomechanical Processing of Steels", Padua, 2008, 1-10 (CD-ROM).
• [19] A. Pichler, S. Traint, T. Hebesberger, P. Stiaszny, E.A. Werner, Processing of thin multiphase steel grades, Steel Research International 78 (2007) 216-223.
• [20] J. Kliber, T. Kursa, I. Schindler, The influence of hot rolling on mechanical properties of high-Mn TWIP steels, Proceedings of the 3rd International Conference "Thermomechanical Processing of Steels", Padua, 2008, 1-12 (CD-ROM).
• [21] A. Grajcar, M. Opiela, G. Fojt-Dymara, The influence of hot-working conditions on a structure of high-manganese steel, Archives of Civil and Mechanical Engineering 9/3 (2009) 49-58.
• [22] L.A. Dobrzański, A. Grajcar, W. Borek, Hot-working behaviour of high-manganese austenitic steels, Journal of Achievements in Materials and Manufacturing Engineering 31/1 (2008) 7-14.
• [23] A. Grajcar, S. Kołodziej, W. Krukiewicz, Corrosion resistance of high-manganese austenitic steels, Archives of Materials Science and Engineering 41/2 (2010) 77-84.