Relationship between microstructure and mechanical properties of strips from microalloyed steel after cold rolling and annealing

• Autorzy: Janošec M. , Schindler I. , Vodárek V. , Místecký E. , Růžička M.
• Konferencja: Metody oceny struktury oraz własności materiałów i wyrobów/sympozjum ( XXII ; 6-8.XI.2007 ; Svratka, Czechy)
• Języki publikacji: EN

Abstrakty

EN

A large testing programme of an HSLA strip steel grade S 500 MC was conducted. The experiment was based on combination of cold rolling, recrystallization annealing, mechanical testing and metallographic examinations. Samples of pickled cuts of hot rolled strip of thickness 4 mm were used for simulation by rolling. Chemical composition of the steel grade was as follows: 0.06 C - 1.38 Mn- 0.24 Si - 0.013 P - 0.005 S - 0.022 Al - 0.03 V - 0.02 Ti - 0.07 Nb (wt %). Samples in the form of strips with dimensions 4 x 25 x 340 mm were rolled in several passes with total height reduction 5 to 75 %. Particular partial strains were realized at room temperature in the housingless, hydraulically pre-stressed laboratory mill QUO (a four-high mill with work rolls of diameter 62 mm) [1]. Afterwards the laboratory mill products were annealed in the vacuum furnace with the protective gas atmosphere consisting of N2+H2. The annealed samples underwent the mechanical testing. The gained results yield stress YS, ultimate tensile strength UTS and their ratio, as well as elongation Ago in %, were summarized in graph (see Fig. 1) in dependence on relative height reduction before annealing - 8 [%]. The found out points were plotted in a coordinate system and the corresponding curves were constructed manually. It was confirmed that by a suitable combination of size of previous cold deformation and parameters of the following recrystallization annealing it is possible to influence a complex of mechanical properties of particular strips. Particular trends of strength and plastic properties correspond to each other. These trends are caused by structure-forming processes (deformation strengthening, recrystallization) which were documented by micrographs (see Fig. 2 for example). Values of strength properties may be influenced by the described way in the range of approximately 100 MPa, which enables - related to applications in practice -to use the obtained results in formation of technological procedures of forming and heat treatment in cold rolling mills.

Słowa kluczowe

EN

microalloyed steel; cold rolling; recrystallization annealing; mechanical testing

• Wydawca: Oficyna Wydawnicza Politechniki Opolskiej
• Czasopismo: Zeszyty Naukowe. Mechanika / Politechnika Opolska
• Rocznik: 2007
• Tom: Vol. 321, z. 89
• Strony: 105--106
• Opis fizyczny: Bibliogr. 5 poz., il., wykr.

Twórcy

autor

Janošec M.

autor

Schindler I.

autor

Vodárek V.

autor

Místecký E.

autor

Růžička M.

• VŠB – Technical University of Ostrava, Faculty of Metallurgy and Materials Engineering, Czech Republic

Bibliografia

• [1] KOLLEROVÁ M., ŽÍDEK M., POCTA B., DEDEK V.: Valcovanie. ALFA, Bratislava, 1991.
• [2] DEDEK V.: Tepelné zpracování ocelových pásu válcovaných za studena. SNTL, Praha, 1964.
• [3] PRASAT N., KUMAR S., KUMAR P., OJHA S. N.: Mechanical properties of coldrolled annealed HSLA steel. Journal of Material Science, 26, 19, 5158-5162.
• [4] http://www.fmmi.vsb.cz/model/
• [5] JANOŠEC M., PALÁT J., SCHINDLER I., MÍSTECKÝ E., RUŽICKA M.: Mechanical properties of a Nb – microalloyed HSLA steels influenced by cold rolling and annealing conditions. In: Steel Strip 2006. Prerov, 2006, 311-318.