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1
Struktura i własności mechaniczne spiekanych stali manganowych obrobionych cieplnie
100%
Sułowski M.
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tom R. 51, nr 5
292-299
PL
Przedstawiono wyniki badań dotyczące wpływu dodatkowej obróbki cieplnej na strukturę i własności konstrukcyjnych spiekanych stali manganowych. Badania prowadzono na spiekanych stalach manganowych o zawartości 3 % mas. manganu, wytwarzanych na drodze jednokrotnego prasowania i spiekania, które następnie poddano zabiegowi odpuszczania w trzech temperaturach 200, 300 i 400°C w atmosferze wodoru; czas trwania procesu wynosił 60 minut. Zaprezentowane wyniki badań świadczą o znaczącym wpływie obróbki cieplnej na własności mechaniczne spiekanych stali manganowych.
EN
It this paper the effect of additional heat treatment operation on the structure and mechanical properties of PM manganese steels had been discussed. The experiments were carried out on sintered steels containing 3 wt.-% Mn, produced during single pressing and sintering cycle, which were subsequently 60 minutes tempered at 200, 300 and 400°C in hydrogen atmosphere. The results show the heat treatment operation has a significant effect on the mechanical properties of sintered structural manganese steels.
2
Content available remote Continuous heating from as-quenched state in a new hot-work steel
100%
Bała P. , Pacyna J. , Krawczyk J.
Archives of Materials Science and Engineering
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2007
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tom Vol. 28, nr 9
517-524
EN
Purpose: This work contains a detailed description of the kinetics of phase transformations during tempering of a new hot-work steel. Moreover, the differences in hardness and microstructure of samples of the investigated steel in relationship to the heat treatment were evaluated. Design/methodology/approach: CHT diagram, illustrating the kinetics of phase transformations during continuous heating (tempering) from as-quenched state of investigated steel, was elaborated using a DT 1000 dilatometer of a French company Adamel. In the case of investigations of the microstructural changes, quenched samples were heated with a heating rate of 0.05°C/s to the temperatures of 150, 280 and 650°C. The microstructure of investigated steel were examined using light microscope Axiovert 200 MAT, scanning electron microscope Stereoscan 120 and transmission JEM200CX microscope. The measurements of hardness were performed with the Vickers HPO250 apparatus. Findings: Heating of the investigated steel from the as-quenched state resulted in the occurrence of 4 primary transformations: precipitation of ε carbide, M3C precipitation, transformation of retained austenite and precipitation of alloy carbides of MC and M2C type, nucleating independently. TEM investigations, focused on the determination of a degree of phase transformations during continuous tempering, showed compatibility of the microstructure with the CHT diagram for tested steel. Research limitations/implications: Description of the kinetics of phase transformations during tempering of a new hot working steel. Practical implications: This results may be used to design new technologies of tempering of this steel and new designed hot-work steels. Originality/value: Characterization of kinetics phase transformations during continuous heating from asquenched state in new hot-work steel. Moreover it was shown, that the heating rate from asquenched state has a strong influence on a hardness after tempering.
3
Content available remote The kinetics of phase transformations during tempering of low alloy medium carbon steel
100%
Bała P. , Pacyna J. , Krawczyk J.
Archives of Materials Science and Engineering
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2007
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tom Vol. 28, nr 2
98-104
EN
Purpose: This work contains a detailed description of the kinetics of phase transformations during tempering of hardened low alloy medium carbon steel. Moreover, the differences in hardness and microstructure of samples of the investigated steel in relationship to the heat treatment were evaluated. Design/methodology/approach: CHT diagram, illustrating the kinetics of phase transformations during continuous heating (tempering) from as-quenched state of investigated steel, was elaborated using a DT 1000 dilatometer of a French company Adamel. Samples were observed using light microscope and TEM. Findings: Heating of the investigated steel from the as-quenched state resulted in the occurrence of 3 primary transformations: precipitation of ε carbide, M3C precipitation and transformation of retained austenite. A light microscope and TEM investigations focused on determination of a degree of phase transformations during continuous tempering, showed compatibility of the microstructure with CHT diagram for tested steel. Research limitations/implications: The new CHT diagram of investigated steel was determined. Practical implications: The obtained CHT diagram may be used to design new technologies of tempering of this steel. Originality/value: The new CHT diagram, characterization of tempering new low alloy medium carbon steel.
4
Wpływ węgla na własności mechaniczne stopów modelowych z wanadem
84%
Dąbrowski R. , Pacyna J.
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tom Vol. 72, nr 10
519-523
PL
W pracy przedstawiono wyniki badań wpływu węgla na zmiany twardości i odporności na pękanie z temperaturą odpuszczania stali zawierających tzw. silne "tło" innych pierwiastków stopowych. Badania wykonano na trzech stopach modelowych o zróżnicowanym stężeniu węgla, zbliżonym stężeniu wanadu oraz w miarę jednakowej zawartości pozostałych pierwiastków stopowych. Wszystkie stopy zahartowane od temperatur granicznej rozpuszczalności węglików i węglikoazotków typu MC wykazały podczas odpuszczania efekt twardości wtórnej. Wykazano silnie niekorzystne oddziaływanie węgla rozpuszczonego w austenicie na odporność na pękanie stopów, zwłaszcza po odpuszczaniu w zakresie występowania twardości wtórnej.
EN
In this paper the effect of carbon content on the hardness and crack resistance as a function of the tempering temperature of steel containing strong background of other alloying elements was described. Investigations were carried out on the three model alloys with different carbon content and similar contents of the other alloying elements. All alloys quenched from the maximum dissolving temperature of MC type carbides and nitrocarbides have shown secondary hardening effect during tempering. It was proved that carbon dissolved in the austenite has strong negative interaction on the crack resistance of alloys particularly after tempering in the secondary hardening range.
5
Content available remote The kinetics of phase transformations during continuous heating from as-quenched state in high-speed steels
84%
Bała P. , Pacyna J.
Archives of Materials Science and Engineering
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2009
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tom Vol. 37, nr 1
5-12
EN
Purpose: The reason for writing this paper was to describe the kinetics of phase transformations during continuous heating from quenched state. In this investigation two high-speed steels of the variable concentration of W and Mo were used. Moreover, the differences in hardness of samples of the investigated steels in relationship to the heating rate were evaluated. Design/methodology/approach : The kinetics of phase transformations during continuous heating (tempering) from as-quenched state of investigated steels, was elaborated using a DT 1000 dilatometer of a French company Adamel. The microstructure of investigations steels in as-quenched state were examined by a light microscope Axiovert 200 MAT, scanning electron microscope Hitachi 3500N and transmission JEM200CX microscope. The measurements of hardness were performed with the Vickers HPO250 apparatus. Findings: Change of heating rate during tempering has strong influence on the temperatures of beginnings and the ends of individual transitions as well as on the accompanying dilatation effects. It was shown that in quenched high-speed steels a part of retained austenite was already transforming during heating for tempering, but its significant part transformed only during cooling process after tempering. Research limitations/implications: It has been found that the substitution of tungsten with molybdenum in HS6-5-2 steel has influenced mainly the stability of retained austenite and the temperature of precipitation beginning of MC (MCs) type carbides. Whereas the precipitation ranges of ε carbide and cementite in both steels are close. Practical implications: Description of phase transformations kinetics during continuous heating from as-quenched state in high-speed steels. Originality/value: This results should be of interest to engineers concerned with design new technologies of steel tempering.
6
Kinetics of phase transformations during tempering of tool steels of a different chromium content
84%
Pacyna J. , Bała P. , Krawczyk J.
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tom Vol. 31, nr 3
243-246
EN
The kinetics of phase transformations during tempering (continuous heating from as-quenched state), in the form of the CHT diagrams (Continuous Heating Transformation) of two tool steels of a different chromium content (2.06 and 2.98%) and a similar carbon (app. 0.8%) and remaining alloying elements content, are presented in the paper. Investigations were performed by means of the DT1000 dilatometer. Transformations in samples during a continuous heating from as-quenched state with heating rates: 0.05÷35°C/s were recorded. The temperature ranges of carbide precipitations as well as transformations of the retained austenite were determined. The influence of a heating rate and an increase of the chromium content on the kinetics of phase transformation during tempering was shown.
PL
W pracy określono kinetykę przemian fazowych przy odpuszczaniu (nagrzewaniu ciągłym ze stanu zahartowanego) w formie wykresów CTPC (Czas-Temperatura-Przemiana) dwóch stali narzędziowych o różnej zawartości chromu 2,06% i 2,98% oraz zbliżonej zawartości węgla (ok. 0.8%) i pozostałych pierwiastków stopowych. Badania wykonano za pomocą dylatometru DT1000. Rejestrowano w próbkach przemiany podczas nagrzewania ciągłego ze stanu zahartowanego z szybkościami 0,05÷35°C/s. Określono zakresy temperatury wydzielania węglików oraz przemiany austenitu szczątkowego. Pokazano wpływ szybkości nagrzewania oraz zwiększenia zawartości chromu na kinetykę przemian fazowych przy odpuszczaniu.
7
Content available remote Computer simulation of microstructure of quenched moulding die
84%
Smoljan B. , Iljkić D. , Tomasic N.
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2014
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tom Vol. 68, nr 2
81--86
EN
Purpose: The research purpose is to upgrade the mathematical modelling and computer simulation of quenching of steel. Design/methodology/approach: The computer simulation of steel hardening is consisted of numerical calculation of transient temperature field in process of cooling, and of numerical calculation of mechanical properties. The hardness has been predicted by the conversion of calculated time of cooling from 800 to 500°C at specimen points to the hardness. The algorithm is completed to solve 3-D situation problems such as the quenching of complex cylinders, cones, spheres, etc. Findings: On the basis of control volume method, the algorithm for prediction of mechanical properties and microstructure distribution in quenched steel specimens with complex geometries has been developed. The established relations were applied in computer simulation of mechanical properties and microstructure distribution of forged steel centrifugal casting pipe mould. The investigated model of steel quenching can be successfully applied in the practice of heat treatment. Research limitations/implications: The investigation was done on carbon and low alloyed steel. The further experimental investigations are needed for final verification of established model. Practical implications: The established algorithms can be used in heat treating practice. Originality/value: Microstructure distribution is estimated based on time relevant for structure transformation, i.e., the cooling time from 800 to 500°C, t8/5.
8
Kinetyka przemian fazowych przy nagrzewaniu ze stanu zahartowanego stali 56NiCrMo7
84%
Dąbrowski R. , Dziurka R.
Hutnik, Wiadomości Hutnicze
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2010
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tom Vol. 77, nr 10
589-593
PL
W pracy przedstawiono oryginalny wykres CTPcO (czas – temperatura – przemiana) przy nagrzewaniu ciągłym ze stanu zahartowanego (odpuszczaniu), stali narzędziowej do pracy na gorąco w gatunku 56NiCrMo7. Wykres sporządzono dla wybranej temperatury austenityzowania równej 860 °C. Dla zilustrowania uzyskanych wyników zamieszczono dylatogram chłodzenia stali od 860 °C oraz dylatogramy nagrzewania ze stanu zahartowanego wraz z ich interpretacją. Na dylatogramach nagrzewania stwierdzono dwa wyraźne efekty dylatacyjne ujemne: pierwszy – pochodzący najprawdopodobniej od wydzielania węglika . oraz drugi – związany z wydzielaniem cementytu stopowego (M3C). Ponadto, zarejestrowano wyraźny efekt dylatacyjny dodatni związany z przemianą austenitu szczątkowego. Nie zaobserwowano natomiast efektu dylatacyjnego dodatniego pochodzącego od niezależnego zarodkowania węglików typu MC. Uzyskane wyniki badań pozwolą w przyszłości zmodyfikować technologię odpuszczania narzędzi wykonanych z badanej stali.
EN
In this paper the original CHT diagram (Continuous Heating Transformation) during heating from as-quenched state) of 56NiCrMo7 hot-work tool steel was presented. The diagram was prepared for the chosen austenitizing temperature 860 °C. To present the way of interpretation of the results, dilatograms of cooling the sample as well heating the samples from as-quenched state were studied. Two negative dilatationes effects were found on the dilatograms of heating: first – related most probably to the precipitations of ĺ carbide and second – related to the recipitations of alloyed cementite (M3C). Moreover, the positive dilatation effect related to the transformation of the retained austenite was registered. The positive dilatations effect related to cendependent nucleation of the carbides of MC type was not observed. Obtained results will let work out the detailed technology of tools tempering made of the investigated steel.
9
Content available remote Effect of heating rate on the phase transformations during tempering of low carbon Cr-Mn-Mo alloy steel
84%
Dziurka R. , Pacyna J. , Tokarski T.
Archives of Materials Science and Engineering
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2013
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tom Vol. 63, nr 1
13--18
EN
Purpose: The effect of heating rate to the tempering temperature on the microstructure and properties of lath martensite tempered at a various temperatures was studied in literature from point of the cemntite precipitations view. It has been shown that cementite dispersion is finer and more uniform in the rapidly heated and tempered than in the slowly heated and tempered specimen. Aim of this work is to investigate the effect of heating rate on the phase transformations during tempering. Design/methodology/approach: The investigations of phase transformations during tempering of the low carbon steel were made on the grounds of dilatometric curves recorded during heating from as-quenched state. Heating to isothermal holding at 350°C was made with two different heating rates (100°C/s and 5°C/s) and was performed by use of the L78 R.I.T.A. dilatometer made by Linseis. The investigations of phase transformations during continuous heating from as-quenched state were performed by use of the DT 1000 dilatometer made by Adamel. Findings: It is possible to reduce probability of the occurrence of some phase transformations in favor of other. The difference in advancement of the various phase transformations can effects on various mechanical properties of the steels. Research limitations/implications: The effect of the heating rates (100°C/s and 5°C/s) during heating from as-quenched state on the phase transformations during isothermal holding at 350°C was submitted. It is expected to carry out further research on the effect of the heating rate on the phase transformations during isothermal holding at different temperatures and their effects on mechanical properties. Practical implications: The obtained information may be used to design new technologies of steels tempering. Originality/value: The new point of view on the tempering of the steels can be assumed.
10
Content available remote The kinetics of phase transformations during the tempering of HS6-5-2 steel
84%
Bała P. , Pacyna J. , Krawczyk J.
Archives of Materials Science and Engineering
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2009
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tom Vol. 35, nr 2
69-76
EN
Purpose: This work contains a detailed description of the kinetics of phase transformations during tempering of hardened HS6-5-2 high-speed steel. Moreover, the microstructure development in tested samples, reflecting the extend of the phase transformations during tempering, was discussed too. Design/methodology/approach: CHT diagram, illustrating the kinetics of phase transformations during continuous heating (tempering) from as-quenched state of investigated steel, was elaborated using a DT 1000 dilatometer of a French company Adamel. The influence of the heating rate on the retained austenite transformation as well as the results of threefold tempering at 560 °C were also determined. Findings: Heating of the investigated steel from the as-quenched state resulted in the occurrence of 4 primary transformations: precipitation of ε carbide, M₃C precipitation, transformation of retained austenite and precipitation of alloy carbides of MC and M₂C type. It was shown that in the quenched high-speed steels a part of retained austenite is already transformed during heating for tempering, but its significant part is transformed only during cooling after tempering as well as during consecutive heatings for temperings. Examination of the microstructure of investigated steel, mainly focused on microstructural development relating to the advancement of transformations during continuous tempering, showed an adequacy of the microstructural changes to CHT diagrams. Research limitations/implications: The new CHT diagram of investigated steel was determined. Practical implications: The obtained CHT diagram may be used to design new technologies of tempering of this steel. Originality/value: The new CHT diagram. Keywords: Tool materials; Tempering; CHT - diagram; Retained austenite
11
Content available remote The kinetics of phase transformations during the tempering of HS6-5-2 high-speed steel
84%
Bała P. , Pacyna J. , Krawczyk J.
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2006
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tom Vol. 18, nr 1-2
47--50
EN
Purpose: The reasons for write this paper was described the kinetics of phase transformations during tempering of hardened HS6-5-2 high-speed steel. Moreover, the influence of the heating rate on the retained austenite transformation. Design/methodology/approach: CHT diagram was with dilatometric method determined. The influence of the heating rate on the retained austenite transformation as well as the results of threefold tempering at 560°C were also determined. Findings: During heating of the samples of the quenched HS6-5-2 steel the occurrence of 4 principal transformations was determined. These are: precipitation of ε carbide, M3C precipitation, transformation of retained austenite and precipitation of alloy carbides of MC and M2C type. It was shown that in the quenched high-speed steels a part of retained austenite is already transformed during heating for tempering, but its significant part is transformed only during cooling after tempering as well as during consecutive heatings for temperings. Research limitations/implications: The new CHT diagram of investigated steel was determined. Practical implications: The obtained CHT diagram may be used to design new technologies of tempering of this steel. Originality/value: The new CHT diagram.
12
Content available remote Przetapianie laserowe stali mikrostopowej typu HSLA
84%
Górka J. , Opiela M. , Stano S.
Przegląd Spawalnictwa
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2016
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tom R. 88, nr 12
18--23
PL
W artykule przedstawiono badania dotyczące przetapiania wiązką laserową stali mikrostopowej typu HSLA – 28MnTiNbVB (Rm = 1060 MPa) o grubości 12 mm. Proces przetapiania został przeprowadzony przy zmiennej energii linowej przetapiania w zakresie od 0,6 do 2,6 kJ/cm. Przeprowadzone badania wykazały, że uzyskane przetopienia charakteryzują się poprawnym kształtem, jednak w ich objętości występują pęcherze gazowe, które mogą pojawić się w związku z bardzo dużymi szybkościami chłodzenia, co powoduje utrudnione wydzielania się gazów ze strefy przetopienia. Pęcherze te powstają w wyniku uwięzienia gazów rozpuszczonych w metalu bądź w wyniku odparowania pierwiastków stopowych. Przetopienia mają strukturę martenzytu listwowego o twardości dochodzącej do 600 HV10. Listwy martenzytu są mniejsze, a drobniejsze wydzielenia węglików są gęściej ułożone niż w materiale rodzimym. Uzyskane wyniki badań wskazują, że stal 28MnTiNbVB wykazuje ograniczoną spawalność w warunkach badania.
EN
In this article examinations of laser beam remelting of microalloyed HSLA steel grade – 28MnTiNbVB (Rm = 1600 MPa), 12 mm thick were presented. Remelting process was carried with variable linear energy in range from 0.6 to 2.6 kJ/cm. Carried examinations have shown that remelted zones have correct geometry, but include gas pores that could be caused by very high cooling rates resulting in hindering gas evacuation from remelted zone. This gas pores are caused by trapping gases dissolved in metal or vaporizing alloying elements. Remelted zone is martensitic with lath structure a hardness of up to 600 HV10. Laths are smaller additionally smaller precipitations are more tightly packed compared to parent material. Examination results show that steel 28MnTiNbVB exhibits limited weldability.
13
Czy nawęglanie jest nadal aktualnym procesem w kształtowaniu warstwy wierzchniej?
84%
Przyłęcka M. , Gęstwa W.
Zeszyty Naukowe Politechniki Świętokrzyskiej. Mechanika
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2001
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tom Z. 75
71-90
PL
W pracy przedstawiono problem nawęglania w świetle literatury i badań własnych. Zaprezentowano w niej wyniki badań i obliczeń według modelu matematycznego składu chemicznego i fazowego warstwy nawęglonej. Uwzględniono w nich obszary dwufazowe (austenit -1- węgliki) oraz rdzeń w powiązaniu z własnościami użytkowymi. Wykazano, że ze wzrostem całkowitej zawartości węgła i temperatury austenityzacji w warstwie dyfuzyjnej temperatura początku przemiany martenzytycznej maleje. Minimalnej wartości temperatury Ms towarzyszy największy udział austenitu szczątkowego, określona zawartość węglików oraz określona wartość ściskających naprężeń własnych. Dzięki temu można uzyskać korzystne własności użytkowe: twardość, wytrzymałość na zginanie, wytrzymałość na zmęczenie kontaktowe i odporność na zużycie ścierne. Zadaniem zaprezentowanego materiału w tej pracy było wykazanie, że nawęglanie jest nadal aktualnym procesem w kształtowaniu własności warstwy wierzchniej.
EN
The paper introduces carburized problem in light literatures and own researches. This work presentes the result ofexperiments and calculations according to the mathematical model of the chemical and phase compositionof carburize layers. It takes into consideration two-phase areas (austenite + carbides) and the core in relation to functional properties. It shows that, as total carbon content and austenization temperature in the case increase, the starting temperature of martensite transformation decreases. The minimum value of Ms temperature is related to the highest fraction of retainedaustenite, a determined carbide fraction and a determined value of compressive internal stresses. That allows obtaining of favourable functional properties, such as hardness, bending resistance, contact fatigue resistance and abrasive wear resistance. Assignment presented of material in this of work was proof, that carburized is still topical in formation of property of surface layer.
14
Content available remote The kinetics of phase transformations during tempering in high-speed steels
84%
Bała P. , Pacyna J.
Journal of Achievements in Materials and Manufacturing Engineering
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2007
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tom Vol. 23, nr 2
15-18
EN
Purpose: This work contains a detailed description of the kinetics of phase transformations during continuous heating from quenched state of HS18-0-1 and HS6-5-2 high-speed steels. Design/methodology/approach: The kinetics of phase transformations during continuous heating (tempering) from as-quenched state of investigated steel, was elaborated using a DT 1000 dilatometer of a French company Adamel. Findings: During heating of previously quenched HS18-0-1 and HS6-5-2 steel samples, the presence of four basic transformations was found, i.e. precipitation of epsilon carbide, precipitation of M3C, transformation of retained austenite and precipitation of alloy carbides of MC and M2C type. It was shown that in quenched high-speed steels a part of retained austenite transforms already during heating for tempering, but its significant part transforms only during cooling process after tempering. Research limitations/implications: The substitution of tungsten with molybdenum in HS6-5-2 steel has influenced mainly the stability of retained austenite and the temperature of precipitation beginning of MC (MCS) type carbides. Practical implications: This results will be used to design new technologies of tempering of these steels. Originality/value: Characterization of kinetics phase transformations during continuous heating from quenched state in high-speed steels.
15
Wpływ węgla na wczesne stadium odpuszczania stali z niklem, krzemem i chromem
84%
Dąbrowski R. , Pacyna J. , Bała P.
Hutnik, Wiadomości Hutnicze
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2006
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tom Vol. 73, nr 10
449-454
PL
W pracy oceniono wpływ węgla na przemiany zachodzące we wczesnym stadium odpuszczania (wydzielanie wąglika e) stopów modelowych z niklem, krzemem i chromem. Badania wykonano metodą dylatometryczną na stopach o specjalnie zaprojektowanym składzie chemicznym, tj. o zmiennym stężeniu węgla, lecz przy stałej zawartości pierwiastków stopowych. Zakres temperatur wczesnego stadium odpuszczania ustalano na podstawie zarejestrowanych cyfrowo dylatogramów nagrzewania ze stanu zahartowanego, które poddano różniczkowaniu. Dla ujednolicenia warunków oceny wybrano jedną szybkość nagrzewania. Wykazano, że pod względem jakościowym, węgiel wpływa na pierwszy etap odpuszczania stopów modelowych z niklem, krzemem i chromem w sposób podobny. Ilościowo jego wpływ jest jednak zróżnicowany. Badania wczesnego stadium odpuszczania będą kontynuowane w celu uzyskania dokładniejszych wyników analizy ilościowej. Autorzy liczą na znalezienie związku między stopniem zaawansowania tego etapu odpuszczania a własnościami stali.
EN
In this paper the effect of carbon content on the transformations taking place at the early stage of tempering (precipitation of the e carbide) of the model alloys with nickel, silicon and chromium addition is evaluated. The alloys with especially designed chemical composition (constant content of alloying elements and varied carbon content) were investigated by means of dilatometric method. The range of temperature of the early stage tempering was established on the basis of differentiated dilatogram curves digitally recorded during heating up step of the previously hardened specimens. In order to unify the experimental conditions, only one heating rate was chosen. It was shown that carbon has a similar influence on a first stage of the tempering of the model alloys containing nickel, silicon and chromium addition when considering a qualitative way of the effect. But when a quantitative way is taken into account, the effect of carbon content is different. Investigations of the early stage of the annealing will be continued for its more accurate quantitative analysis. Authors are expecting that there is a relationship between an intensity of this stage of tempering and steel’s properties.
16
Kinetyka przemian fazowych przy nagrzewaniu ze stanu zahartowanego nowej stali stopowej o dużej zawartości węgla
84%
Pacyna J. , Bała P. , Skrzypek T.
Hutnik, Wiadomości Hutnicze
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2006
|
tom Vol. 73, nr 2
46-49
PL
W pracy określono kinetykę przemian fazowych przy nagrzewaniu ciągłym (odpuszczaniu) ze stanu zahartowanego w postaci wykresu CTPc stopni (Czas - Temperatura - Przemiana) nowej stali stopowej zawierającej 1,22 %C. Na dylatogramach nagrzewania ze stanu zahartowanego wskazano temperatury charakterystyczne, użyte do wykonania CTPc tej stali. Ponadto, pokazano różnice w twardościach próbek badanej stali w zależności od stopnia zaawansowania przemian przy odpuszczaniu, jak również zamieszczono dokumentację metalograficzną.
EN
In the paper kinetics of phase transformations during continuous heating (tempering) from the hardened condition has been specified in from of a CHT diagram (Continuous Heating Transformations) of a new alloy steel containing 1,22 %C. In the dilatograms of heating from hardened condition characteristic temperatures used for the CHT diagram have been indicated. Moreover some differences in the hardness of the investigated steel samples depending on the level of advancement of changes at tempering have been shown, as well as metallographic documentation has been included.
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Content available remote Hartowanie i odpuszczanie walcowanego na gorąco żeliwa sferoidalnego
84%
Szykowny T. , Giętka T.
Archiwum Odlewnictwa
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2006
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tom R. 6, nr 19
349-354
PL
Próbki niskomiedziowego żeliwa sferoidalnego o początkowej grubości 3mm austenityzowano w temperaturze 920 C, walcowano ze zgniotem 33% i oziębiano w wodzie. Następnie przeprowadzono odpuszczanie w temperaturze 250 - 650 C. Dla celów porównawczych przeprowadzono taką samą obróbkę cieplną żeliwa nieodkształcanego. Wykonano badania metalograficzne, mikrofraktograficzne, dyfrakcyjne rentgenowskie oraz pomiary twardości.
EN
The samples of low-copper, ductile cast iron withe the initial thickness 3 mm were austenitized in temperature 920 C, they were strain rolled 33% and they were cooled down in the water. Next ductile cast iron was tempered in temperature 250 - 600 C. In comparison aims it was made the same heat treating of unstrained ductile cast iron an. The researches were performed using the following methods: metallography, fractography, X-ray diffraction and take measurements and hardnesses
18
Content available The effect of heat treatment on mechanical properties of 42CrMo4 steel
84%
Çalık A. , Dokuzlar O. , Uçar N.
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2020
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tom Vol. 98, nr 1
5--10
EN
Purpose: In this study, the effect of heat treatment on the microstructure and mechanical properties of 42CrMo4 steel were investigated. Design/methodology/approach: The samples were annealed at 860°C for 120 min. followed by oil quenching and then tempered at temperatures between 480 and 570°C for 120 min. The microstructure of untreated 42CrMo4 steel mainly consists of pearlite and ferrite whereas the microstructure was found to be as a martensitic structure with a quenching process. Findings: The results showed that there is an increase in yield stress, ultimate tensile stress, hardness and impact energy, while elongation decreases at the end of the quenching process. Conversely, yield stress, ultimate tensile stress and hardness decrease slightly with the increasing of tempering temperature, while elongation and impact energy increase. Research limitations/implications: Other types of steels can be heat treated in a wider temperature range and the results can be compared. Practical implications: It is a highly effective method for improving the mechanical properties of heat treatment materials. Originality/value: A relationship between the mechanical properties and the microstructure of materials can be developed. The heat treatment is an effective method for this process.
19
Content available remote Effect of carbon content upon the early stage of tempering of steel with Mn and V addition
84%
Dąbrowski R. , Pacyna J.
Archives of Materials Science and Engineering
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2007
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tom Vol. 28, nr 10
585-588
EN
Purpose: In this paper the effect of carbon content on the transformations taking place at the early stage of tempering (precipitation of the ε carbide) of the model alloys with manganese and vanadium addition is evaluated. Design/methodology/approach: The alloys with specially designed chemical composition (constant content of alloying elements and varied carbon content) were investigated by means of dilatometric method. The range of temperature of the early stage tempering was established on the basis of differentiated dilatogram curves digitally recorded during heating up step of the previously hardened specimens. In order to unify the experimental conditions, only one heating rate was chosen. Findings: It was shown that carbon has a similar influence on the first stage of the tempering of the model alloys containing manganese and vanadium addition when considering a qualitative way of the effect. But when a quantitative way is taken into account, the effect of carbon content is different. Research limitations/implications: Investigations of the early stage of the tempering will be continued for its more accurate quantitative analysis. Authors are expecting that there is a relationship between an intensity of this stage of tempering and steel’s properties. Practical implications: The results of the research have strong cognitive meaning. It is possible that in the future they may be used for designing of chemical composition of steels for which presently only the low-temperature tempering is provided. Originality/value: The results contained in this paper have very high cognitive significance and in the future it may be possible to use them for elaboration of detailed heat treatment technology of new steels, which are anticipated to be subjected to low-temperature tempering only.
20
Content available remote The influence of kinetics of phase transformations during tempering on high-speed steels mechanical properties
84%
Bała P. , Pacyna J.
Journal of Achievements in Materials and Manufacturing Engineering
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2010
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tom Vol. 43, nr 1
64-71
EN
Purpose: The main purpose of the presented paper was the determination of the influence of the phase transformation kinetics, at tempering, on the properties of high-speed steels. In order to achieve this aim investigations of the influence of continuous heating and isothermal tempering from the as-quenched state on the investigated steels hardness were performed. The advancement degree change obtained by changing the heating rate and by pre-tempering was applied in strength properties studies. Design/methodology/approach: Due to a high brittleness of tested steels it was decided to test their strength by means of the static bend test. The tests were carried out on 5 samples using the INSTRON testing machine. The microstructure of investigated steels in the as-quenched state was examined by the light microscope Axiovert 200 MAT and the scanning electron microscope Hitachi 3500 N. The measurements of hardness were performed with the Vickers HPO250 apparatus. Findings: Changing heating rates for tempering one can influence steel properties. Better results are achieved when steels are heated up to the tempering temperature with the higher rate. The heating rate increased from 15°C/min to 300°C/min improved the investigated steels bending strength by 8%. Research limitations/implications: Phase transformations at tempering, being diffusive transformations, are characterised by the determined kinetics depending on a temperature and time of heating. Complexity of processes occurring at tempering, as well as the diversity of influencing factors creates the possibility of searching for prolonging the life-span of tools made of high-speed steels. Regardless that only two, well known high-speed steels HS18-0-1 and HS6-5-2 were tested, the obtained results can be referred to the whole group of high-speed steels. Practical implications: On the basis of the obtained results it is possible to select the tempering parameters in such a way as to achieve the optimal combination of strength and plastic properties needed for the anticipated application of the given high-speed steel. Originality/value: This results should be of interest to engineers concerned with designing the new technologies of high-speed steels tempering.
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