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Доклад на д-р инж. Богомил Великов Колев по металофизика публикуван в Украйна
Yu. S. Nechaev,
Мепижялофкл. кивейшие технол. / Metallofiz. Noveishie Tekhnol 1999, т. 21, №3,c. 69—77
© Інститут металофізики ім. Г. В. Курдюмова HAH України, 1999. Надруковано в Україні.
ФАЗОВЫЕПРЕВРАЩЕНИЯ
УДК 539.2
PACS numbers: 64.60.My, 64.7O.Kb, 64.7S.+g, 81.30.Bx, 81.30.Mh, 8l.40.Cd
B. Kolev Institute for Metal Science, Bulgarian Academy of Sciences, 67 "Shipchenski Prohod" Str., 1574 Sofia, Bulgaria THERMAL METASTABILITY IN HEATING AND COOLING OF SOME AUSTENITIC FERROUS ALLOYS-THEORETICAL FOUNDATIONS According to the suggested hypothesis, the basic processes, respectively the solid phase reactions caused by ageing of homogenized and quenched austenitic (A) alloys of the Fe—Cr—Mn—C and Fe— Afn—(Cr)—C systems with and without nitrogen, are determined by the rate of supersaturation of the solid solution with C, N, C+N and by their interaction with the available "substitutive" elements (carbide- and nitride-forming elements) depending on their quantity, affinity and diffusion coefficient as well as on their influence over the equilibrium curves of the state diagram—a polythermal cross-section. Висловлено гіпотезу, згідно з якою основні процеси, зокрема твердофазні реакції в процесі старіння гомогенізованих та загартованих аустенітних сплавів в системах Fe—Cr—Mn—C і Fe—Mn—(Cr)—C з азотом чи без нього, визначаються швидкістю пересичення твердого розчину вуглецем (С), азотом (N) та C+N, а також їх взаємодією з наявними елементами «заміщення» (карбо- та нітридоутворючі), в залежності від їх кількості, спорідненості та коефіцієнта дифузії, а також від їх впливу на криві рівноваги діаграми станів — політермічний переріз. Высказана гипотеза, согласно которой основные процессы, в частности твердофазные реакции в процессе старения гомогенизированных и закаленных аустенитных сплавов Fe—О— Мп—С и Fe—Mn—(Сг) с азотом или без него, определяются скоростью пересыщения твердого раствора углеродом (С), азотом (N) и C+N, а также их взаимодействием с имеющимися элет ментами «замещения» (карбо- и нитридообразующие), в зависимости от их количества, сродства и коэффициента диффузии, а также от их воздействия на кривые равновесия диаграммы состояния — политермическое сечение. Key words: austenite ferrous alloys, heating, cooling, thermal metastability, theory, ageing.
1. Introduction A theory about structural processes caused by heating and cooling (ageing) of homogenized and quenched austenite alloys of the Fe—Cr—Mn—С system with and without nitrogen are particularly not available in the literature sources so far. The experimental data concern nitrided stainless forged steels containing less than 0.1% С and more than 14-16% Cr [1, 2, 7]. Examinations were conducted after plastic deformation [1, 2, 7]. The mechanism of process is not clarified so far. Ex-
perimental and theoretical works consider the structural changes caused by ageing of homogenized and quenched alloys of the above mentioned systems containing 0.3—4% C, 0—30% Cr by Mn from 7-10% up to 22-30% without, overequilibrium nitrogen contents. The purpose of the present work is to sum up the former experimental and theoretical material produced by the author and to formulate a hypothesis (theory) for the structural processes caused by "ageing" of preliminarily homogenized and quenched austenite alloys of the above-mentioned systems.
Fig. 1. Structure diagram of the Fe-Cr-Mn-C-N system, 1150°C, 6 hours, H2, 0.9-19% Mn [1, 6-8].
2. Summarized Results and Discussion The hypothesis is based on the studies made within the period 1975—1997 for following alloys" groups: a) Fe-Cr-Mn-C-N respectively Fe-Cr-Mn-
N systems (stainless steels): С = 0.05-2.8%; Si =
=0.6-2.5%; Mn = 5-15%; Cr = 7-23%; N = 0.15-
1.325%; S, P / + Me.C/, Me,N/ + Me^CN);, MexCy aMe; С + МетС,,; b) Fe—N-systems: yN->aN + Fe4N; Fe-Me-N; aMN; C->aMiN + M«N^ c) Fe—C—N-systems:
Yc,N->ac,N+. Fe3C + Fe4N; {Fe^CN),};
Fe-Me-C-N: yMiti->MexCy+ MeJtNJ,{Fe;t(CN)),}+a. Ferromagnetic phases: Me3C (Fe3C, Mn3C); Me4N (Fe4N, Mn4N); non-magnetic phases: Me7C3, Me23C6> Me2N, Me23(CN)6 [1-3, 5, 6, 7-10,12-15]. B. Alloyed austenite alloys. Mold cooling at
diverse cooling rates (cast thickness), furnace an
nealing, heating (ageing, tempering) of the ho
mogenized and quenched Л-alloys. I. Non-magnetic eutectoid reactions. Nonmagnetic pearlite. Processes below SE respectively PS (Figs. 3, 6): a) Fe—Cr—Mn—N: y->y" + MexN + a + MeMe",
where y" is impoverished solid solution; a is a-phase;
MeMe" are intermetallic compounds: FeCr, CrMn,
etc.; Me^N are new formed secondary nitrides; b) Fe—Cr— Mn-C-systems: y-»y" + Me*Cy, where
Ме,Су are new formed (secondary) carbides; c) Fe-Cr-Mn-C—N-systems: y->y" + МехС,,+
Fig. 8. Polythermal cross-section. Fe-Mn-C system by 20% Mn [7, 15, 17]. + Me^Me^CN),}. II. Ferromagnetic eutectoid reactions. Magnetic pearlite. 7a transformations (Figs. 6—9). a) Fe—Mn—N-system: Probable reactions: у -» у + MexN; у -» у" + a + т, + Me,N; у-► a + + Me,N (Г, a + у + Me3C—medium- magnetic pearlite; у -> a + Me3C—high-magnetic pearlite (7>T2
© Інститут металофізики ім. Г. В. Курдюмова HAH України, 1999. Надруковано в Україні.
ФАЗОВЫЕПРЕВРАЩЕНИЯ
УДК 539.2
PACS numbers: 64.60.My, 64.7O.Kb, 64.7S.+g, 81.30.Bx, 81.30.Mh, 8l.40.Cd
B. Kolev Institute for Metal Science, Bulgarian Academy of Sciences, 67 "Shipchenski Prohod" Str., 1574 Sofia, Bulgaria THERMAL METASTABILITY IN HEATING AND COOLING OF SOME AUSTENITIC FERROUS ALLOYS-THEORETICAL FOUNDATIONS According to the suggested hypothesis, the basic processes, respectively the solid phase reactions caused by ageing of homogenized and quenched austenitic (A) alloys of the Fe—Cr—Mn—C and Fe— Afn—(Cr)—C systems with and without nitrogen, are determined by the rate of supersaturation of the solid solution with C, N, C+N and by their interaction with the available "substitutive" elements (carbide- and nitride-forming elements) depending on their quantity, affinity and diffusion coefficient as well as on their influence over the equilibrium curves of the state diagram—a polythermal cross-section. Висловлено гіпотезу, згідно з якою основні процеси, зокрема твердофазні реакції в процесі старіння гомогенізованих та загартованих аустенітних сплавів в системах Fe—Cr—Mn—C і Fe—Mn—(Cr)—C з азотом чи без нього, визначаються швидкістю пересичення твердого розчину вуглецем (С), азотом (N) та C+N, а також їх взаємодією з наявними елементами «заміщення» (карбо- та нітридоутворючі), в залежності від їх кількості, спорідненості та коефіцієнта дифузії, а також від їх впливу на криві рівноваги діаграми станів — політермічний переріз. Высказана гипотеза, согласно которой основные процессы, в частности твердофазные реакции в процессе старения гомогенизированных и закаленных аустенитных сплавов Fe—О— Мп—С и Fe—Mn—(Сг) с азотом или без него, определяются скоростью пересыщения твердого раствора углеродом (С), азотом (N) и C+N, а также их взаимодействием с имеющимися элет ментами «замещения» (карбо- и нитридообразующие), в зависимости от их количества, сродства и коэффициента диффузии, а также от их воздействия на кривые равновесия диаграммы состояния — политермическое сечение. Key words: austenite ferrous alloys, heating, cooling, thermal metastability, theory, ageing.
1. Introduction A theory about structural processes caused by heating and cooling (ageing) of homogenized and quenched austenite alloys of the Fe—Cr—Mn—С system with and without nitrogen are particularly not available in the literature sources so far. The experimental data concern nitrided stainless forged steels containing less than 0.1% С and more than 14-16% Cr [1, 2, 7]. Examinations were conducted after plastic deformation [1, 2, 7]. The mechanism of process is not clarified so far. Ex-
perimental and theoretical works consider the structural changes caused by ageing of homogenized and quenched alloys of the above mentioned systems containing 0.3—4% C, 0—30% Cr by Mn from 7-10% up to 22-30% without, overequilibrium nitrogen contents. The purpose of the present work is to sum up the former experimental and theoretical material produced by the author and to formulate a hypothesis (theory) for the structural processes caused by "ageing" of preliminarily homogenized and quenched austenite alloys of the above-mentioned systems.
Fig. 1. Structure diagram of the Fe-Cr-Mn-C-N system, 1150°C, 6 hours, H2, 0.9-19% Mn [1, 6-8].
2. Summarized Results and Discussion The hypothesis is based on the studies made within the period 1975—1997 for following alloys" groups: a) Fe-Cr-Mn-C-N respectively Fe-Cr-Mn-
N systems (stainless steels): С = 0.05-2.8%; Si =
=0.6-2.5%; Mn = 5-15%; Cr = 7-23%; N = 0.15-
1.325%; S, P / + Me.C/, Me,N/ + Me^CN);, MexCy aMe; С + МетС,,; b) Fe—N-systems: yN->aN + Fe4N; Fe-Me-N; aMN; C->aMiN + M«N^ c) Fe—C—N-systems:
Yc,N->ac,N+. Fe3C + Fe4N; {Fe^CN),};
Fe-Me-C-N: yMiti->MexCy+ MeJtNJ,{Fe;t(CN)),}+a. Ferromagnetic phases: Me3C (Fe3C, Mn3C); Me4N (Fe4N, Mn4N); non-magnetic phases: Me7C3, Me23C6> Me2N, Me23(CN)6 [1-3, 5, 6, 7-10,12-15]. B. Alloyed austenite alloys. Mold cooling at
diverse cooling rates (cast thickness), furnace an
nealing, heating (ageing, tempering) of the ho
mogenized and quenched Л-alloys. I. Non-magnetic eutectoid reactions. Nonmagnetic pearlite. Processes below SE respectively PS (Figs. 3, 6): a) Fe—Cr—Mn—N: y->y" + MexN + a + MeMe",
where y" is impoverished solid solution; a is a-phase;
MeMe" are intermetallic compounds: FeCr, CrMn,
etc.; Me^N are new formed secondary nitrides; b) Fe—Cr— Mn-C-systems: y-»y" + Me*Cy, where
Ме,Су are new formed (secondary) carbides; c) Fe-Cr-Mn-C—N-systems: y->y" + МехС,,+
Fig. 8. Polythermal cross-section. Fe-Mn-C system by 20% Mn [7, 15, 17]. + Me^Me^CN),}. II. Ferromagnetic eutectoid reactions. Magnetic pearlite. 7a transformations (Figs. 6—9). a) Fe—Mn—N-system: Probable reactions: у -» у + MexN; у -» у" + a + т, + Me,N; у-► a + + Me,N (Г, a + у + Me3C—medium- magnetic pearlite; у -> a + Me3C—high-magnetic pearlite (7>T2
Доклад на д-р инж. Богомил Великов Колев...
Доклад на д-р инж. Богомил Великов Колев...
Доклад на д-р инж. Богомил Великов Колев...
Доклад на д-р инж. Богомил Великов Колев...
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