DOI: 10.52150/2522-9117-2018-32-349-360

Bobyr Sergey Vladimirovich, Dr. Sci. (Engin.), Leading Research Scientist, Iron and Steel Institute named after Z.I. Nekrasov of the NAS of Ukraine, Academican Starodubova square, 1, Dnipro, Ukraine, 49107; e-mail: svbobyr07@gmail.com, ORCID 0000-0001-6816-1554

Borisenko Andrey Yurievich, PhD (Engin.), Research Scientist, Iron and Steel Institute named after Z.I. Nekrasovof the NAS of Ukraine, Academican Starodubova square, 1, Dnipro, Ukraine, 49107; e-mail: asbor@ua.fm

Kuksa Oleg Volodimirovich, PhD (Engin.), Researcher, Iron and Steel Institute named after Z.I. Nekrasov of the NAS of Ukraine, Academican Starodubova square, 1, Dnipro, Ukraine, 49107

Loshkarev Dmitry Valerievich, Lead Engineer, Iron and Steel Institute named after Z.I. Nekrasov of the NAS of Ukraine, Academican Starodubova square, 1, Dnipro, Ukraine, 49107

Analysis of phase-structural transformations during cooling of steels, taking into account the deformations and stresses

Abstract. The aim of the work is to study the phase-structural transformations during cooling of carbon and low-alloy steels, taking into account the resulting structural deformations and stresses. Low-alloyed steels with different content of alloying elements – chromium, molybdenum, nickel and steel, micro-alloyed with vanadium were chosen as the object of research. The dilatograms of steel samples were used to find the relative expansion of the steel sample before the start of austenite phase transformation (DA) and the relative expansion of the steel sample during austenite phase transformation (DFТ), which are associated with the relative elongation of the sample through a constant factor K. The parameter DA allows you to find structural stresses that arise in supercooled austenite steel in the presence of a temperature gradient. The parameter DFТ characterizes the stresses created by the phase transformation of austenite. As a result of the performed regression analysis, dependences were obtained that link the chemical composition of the steel, its cooling rate, and the parameters DА and DFТ. The analysis of phase-structural transformations during the cooling of the steel with the occurring deformations and stresses. An empirical relationship has been established between the temperatures of the beginning and end of the phase transformation of austenite in steel, the physicochemical parameters d and Zy, the cooling rate, and the deformation parameters when the austenite is cooled DA and the phase transformation DFТ. Confirmed the adequacy of the constructed equations. The obtained regression equations make it possible to calculate the deformation
parameters DA and DFТ and critical points of the steel Ac1 and Ac3.
Keywords: carbon and low-alloy steels, cooling, phase-structural transformations, temperature, deformations and stresses.

Reference
1. Burkin S.P. Ostatochnyye napryazheniya v metalloproduktsii : uchebnoye posobiye. [S.P. Burkin, G.V.Shimov, Ye.A.Andryukova]. —Yekaterinburg :Izd-vo Ural. un-ta, 2015. — 248 s.
2. Abramov V.V. Napryazheniya i deformatsii pri termicheskoy obrabotke stali. – K.: Vishcha shkola, 1985. – 133s.
3. Zin Cher K., Martinovich I.I., Faldin A.A. Vliyaniye napryazheniy i deformatsiy na beynitnoye prevrashcheniye v stalyakh. Novyye konstruktsionnyye stali i metody ikh uprochneniya: Materialy seminara. – M.: MDNTP, 1984. – S.41-45.
4. Zaymovskiy V.A., Faldin A.A. Effekt zapominaniya formy i strukturnaya nasledstvennost’ v stali 40KHN3M. Fizika metallov i metallovedeniye, 1984. – T.58. – Vyp.1. – S.106-112.
5. Zaymovskiy V.A. O prichinakh uskoreniya beynitnogo prevrashcheniya pri nizkotemperaturnoy deformatsii austenite. [V.A.Zaymovskiy, V.A.Martinovich, O.V.Samedov, A.A.Faldin]. Fizika metallov i metallovedeniye, 1986. – T.61. – Vyp.4. – S.760-768.
6. Romanov P.V., Radchenko R.P. Prevrashcheniya austenita pri nepreryvnom okhlazhdenii stali (Atlas termokineticheskikh diagramm). – Novosibirsk, Izd-vo SO AN SSSR, 1960 . – 403s.
7. Prikhod’ko E.V. Effektivnost’ kompleksnogo legirovaniya staley i splavov. – K.: Naukova dumka, 1995. – 292s.
8. Belous M.V., Braun M.P. Fizika metallov – K.: Vishcha shkola, 1985. –
373s.
9. Bazhanov V. L. Mekhanika deformiruyemogo tverdogo tela: uchebnoye
posobiye dlya bakalavriata i magistratury. – M.: Izdatel’stvo Yurayt, 2018.
— 178 s.
10. Nadai A. Plastichnost’ i razrusheniye tverdykh tel. T.2 – M.: Mir, 1960 –
S.461.

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