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1

Analiza dylatometryczna przemian fazowych podczas nagrzewania zahartowanego stopu Ti6Al4V

Dąbrowski R.

Rudy i Metale Nieżelazne

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2013

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R. 58, nr 2

84-89

PL

W artykule zaprezentowano fragment oryginalnego wykresu CTPc [stopni] (czas-temperatura-przemiana) przy nagrzewaniu ciągłym zahartowanego dwufazowego stopu tytanu w gatunku Ti6Al4V. Wykres wykonano dla wybranej temperatury wyżarzania (w zakresie jednofazowym [beta]) równej 1020 [stopni]C. Dla zilustrowania uzyskanych wyników zamieszczono wybrane dylatogramy nagrzewania zahartowanego stopu wraz z ich interpretacją. Na dylatogramach nagrzewania z szybkościami w zakresie 0,05-35°C/s obserwuje się wyraźny efekt dylatacyjny ujemny związany prawdopodobnie z przemianą fazy martenzytycznej [alfa]' - [alfa]+[beta]. W ww. zakresie szybkości nagrzewania początek tej przemiany odnotowano w zakresie temperatur 390-525 [stopni]C. Stwierdzono, że w zakresie niskich temperatur odpuszczania (50-200 [degrees]C) trudno jest jednoznacznie rozstrzygnąć o rodzaju zachodzących przemian w oparciu tylko o analizę dylatometryczną. Ten zakres temperatur wymaga użycia dodatkowych metod badawczych, np. TEM. Wyniki badań posłużą do optymalizacji technologii obróbki cieplnej oraz uzyskania wymaganych własności mechanicznych stopu Ti6Al4V.

EN

The fragment of the original CHT diagram (continuous-heating-transformation) at continuous heating of the quenched, diphase titanium alloy Ti6Al4V, are presented in the paper. The diagram was made for the selected annealing temperature (in the single phase [beta] range) being equal 1020 [degrees]C. To illustrate the obtained results the selected dilatograms of heating the quenched alloy together with their interpretation are included in the paper. When heating is carried out at a rate: 0.05-35 [degreesw]C/s a distinct negative dilatation effect is seen in the dilatograms. It is probably related to the martensite phase transformation [alfa]'- [alfa]+[beta]. The start of this transformation - within the mentioned above heating rate - was seen in the temperature range 390-525 [degrees]C. It is stated in the paper, that at low tempering temperatures (50-200 [degrees]C) it is difficult to decide explicitly, based on the dilatometric analysis only, which kind of transformation occurs. This temperature range requires using additional investigation methods, e.g. TEM. The obtained results will be applied for the optimisation of the heat treatment technology and for achieving the required mechanical properties of the Ti6Al4V alloy.

2

Analiza dylatometryczna przemian fazowych podczas odpuszczania stali 56NiCrMo7

Dąbrowski R., Dziurka R.

Hutnik, Wiadomości Hutnicze

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2012

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Vol. 79, nr 10

748--752

PL

W artykule zaprezentowano oryginalny wykres CTPc° (czas – temperatura – przemiana) dla przemian zachodzących podczas odpuszczania stali narzędziowej do pracy na gorąco w gatunku 56NiCrMo7. Wykres wykonano dla wybranej temperatury austenityzowania równej 830 °C. Uzyskane wyniki zilustrowano za pomocą dylatogramu chłodzenia stali od 830 °C oraz dylatogramów nagrzewania ze stanu zahartowanego (odpuszczania) wraz z ich interpretacją. Na dylatogramach nagrzewania stwierdzono dwa wyraźne efekty dylatacyjne ujemne: pierwszy − pochodzący najprawdopodobniej od wydzielania węglika ε 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 zmodyfikować technologię odpuszczania narzędzi wykonanych z badanej stali.

EN

In this paper the original CHT diagram (Continuous - Heating - Transformation) during tempering of 56NiCrMo7 hot-work tool steel was presented. The diagram was prepared for the chosen austenitizing temperature (830 °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 dilatation effects were found on the dilatograms of heating: first - related most probably to the precipitations of ε carbide and second – related to the precipitations 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 independent nucleation of the carbides of MC type was not observed. Obtained results will let work out the detailed technology of tempering of tools made of the investigated steel.

3

Kinetyka przemian fazowych przy nagrzewaniu ze stanu zahartowanego stali 56NiCrMo7

Dąbrowski R., Dziurka R.

Hutnik, Wiadomości Hutnicze

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2010

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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.

4

The kinetics of phase transformations during the tempering of HS6-5-2 steel

Bała P., Pacyna J., Krawczyk J.

Archives of Materials Science and Engineering

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2009

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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

5

The kinetics of phase transformations during tempering of Cr-Mo-V medium carbon steel.

Bała P., Pacyna J., Krawczyk J.

Journal of Achievements in Materials and Manufacturing Engineering

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2007

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Vol. 20, nr 1-2

79-82

EN

Purpose: The reasons for writing this paper was to describe the kinetics of phase transformations during tempering of hardened Cr-Mo-V 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 was determined with dilatometric method. Samples were observed using with TEM. Findings: During heating of the samples of the quenched Cr-Mo-V medium carbon steel the occurrence of 3 principal transformations was determined. These are: precipitation of epsilon carbide, M3C precipitation and transformation of retained austenite. A 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 Cr-Mo-V steel.

6

The kinetics of phase transformations during tempering in the new hot working steel

Bała P., Pacyna J., Krawczyk J.

Journal of Achievements in Materials and Manufacturing Engineering

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2007

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Vol. 22, nr 2

15-18

EN

Purpose: This work contains a detailed description of the kinetics of phase transformations during tempering of new hot working steel. Moreover, the differences in 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 DT1000 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 degree centigrade/s to the temperatures of 210, 320 and 420 degrees centigrade. The microstructure of investigated steel were examined using transmission JEM 200 CX microscope. Findings: Heating of the investigated steel from the as-quenched state resulted in the occurrence of 4 primary transformations: precipitation of epsilon carbide, M3C precipitation, transformation of retained austenite and precipitation of alloy carbides of MC and M2C type, nucleating independently. 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 hot working steel.

7

Kinetyka przemian fazowych przy odpuszczaniu stali Ni-Cr-Mo zawierających 0,10+1,21 % węgla

Pacyna J., Zając G., Dąbrowski R.

Hutnik, Wiadomości Hutnicze

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2007

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Vol. 74, nr 3

133-138

PL

W artykule oceniono wpływ węgla w zakresie 0,10-1,21 % na kinetykę przemian fazowych zachodzących podczas odpuszczania stali Ni-Cr-Mo. Badania wykonano metodą dylatometryczną na stopach modelowych o specjalnie zaprojektowanym składzie chemicznym, dla których wykonano wykresy CTPc° (czas - temperatura - przemiana) przy odpuszczaniu (nagrzewaniu) ciągłym ze stanu zahartowanego. Wykazano, że przy stężeniu 0,10 % węgla nie zachodzi wydzielanie węglika e, a w zakresie stężeń 0,31-1,21 % pierwiastek ten praktycznie nie wpływa na zakres jego wydzielania. Ze wzrostem stężenia od 0,10 do 0,79 %, węgiel rozszerza zakres wydzielania cementytu, natomiast nie wpływa na zakres przemiany austenitu szczątkowego.

EN

In this paper the effect of carbon content (0.10-1.21 wt. %) on the kinetics of the phase transformation during tempering of Ni-Cr-Mo steels was studied. Model alloys having special chemical composition were investigated. Dilatometric data were acquired on continuous heating of as-quenched specimens to generate Continuous - Heating - Transformation (CHT) diagrams. It was shown that there is no e carbide precipitation for the carbon content of 0.1 wt. %. Between 0.31-1.21 wt. % carbon, it has a negligible effect on the precipitation range ofe carbide. A rise in the carbon content from 0.10 to 0.79 wt. %, increases the cementite precipitation range without affecting the transformation of the retained austenite.

8

The influence of the kinetics of phase transformations during tempering on the structure development in a high carbon steel

Bała P., Pacyna J., Krawczyk J.

Archives of Metallurgy and Materials

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2007

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Vol. 52, iss. 1

113-120

EN

This work contains a detailed description of the kinetics of phase transformations occurring during tempering of a new, high carbon (1.22%C) Cr-Mo-V steel. The temperature ranges of the phase transformations occurring during heating from the quenched state (tempering) were determined from dilatometric tests. An interpretation of dilatograms of heating from the as-quenched state was also presented. The temperature ranges of the observed transformations during tempering of investigated steel were presented on CHT (Continuous Heating Transformations) diagrams. Moreover, the microstructure development in tested samples, reflecting the extend of the phase transformations during tempering, was discussed too.

PL

Wpracy zamieszczono szczegółowy opis kinetyki przemian fazowych przy odpuszczaniu nowej, wysokowęglowej (1.22%C) stali chromowo-molibedenowo-wanadowej. Na podstawie badań dylatometrycznych wyznaczono zakresy występowania przemian fazowych podczas nagrzewania ze stanu zahartowanego (odpuszczania stali). W pracy zamieszczono również interpretacje dylatogramów nagrzewania ze stanu zahartowanego. Zakresy poszczególnych przemian przy odpuszczania badanej stali przedstawiono na wykresie CTPcO. Ponadto, zamieszczono mikrostruktury próbek w zależności od stopnia zaawansowania w nich przemian przy odpuszczaniu.

9

The kinetics of phase transformations during tempering of low alloy medium carbon steel

Bała P., Pacyna J., Krawczyk J.

Archives of Materials Science and Engineering

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2007

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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.

10

Continuous heating from as-quenched state in a new hot-work steel

Bała P., Pacyna J., Krawczyk J.

Archives of Materials Science and Engineering

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2007

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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.

11

The kinetics of phase transformations during the tempering of HS6-5-2 high-speed steel

Bała P., Pacyna J., Krawczyk J.

Journal of Achievements in Materials and Manufacturing Engineering

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2006

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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

Kinetyka przemian fazowych przy nagrzewaniu ze stanu zahartowanego nowej stali stopowej o dużej zawartości węgla

Pacyna J., Bała P., Skrzypek T.

Hutnik, Wiadomości Hutnicze

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2006

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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.

13

Wpływ węgla na przemiany podczas odpuszczania stali zawierających około 0,4 % wanadu i silne tło innych pierwiastków stopowych

Dąbrowski R., Pacyna J.

Hutnik, Wiadomości Hutnicze

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2005

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Vol. 72, nr 12

578-582

PL

W pracy przedstawiono trzy wykresy CTPc° (czas - temperatura - przemiana) przy odpuszczaniu (nagrzewaniu) ciągłym dla stopów o zbliżonym stężeniu wanadu, zróżnicowanym stężeniu węgla i silnym "tle" pozostałych pierwiastków stopowych. Wykazano, że o wydzielaniu węglika v. w badanych stopach decyduje przede wszystkim stężenie węgla w martenzycie. Temperatury początku i końca wydzielania niezależnie zarodkujących węglików wanadu typu MC zależą nie tylko od stężenia węgla w badanych stopach, ale także od szybkości ich nagrzewania podczas odpuszczania.

EN

The work presents three CHTdiagrams (continuous - heating - transformation) at continuous tempering (heating) for alloys of similar vanadium concentration, various carbon concentration and strong background of other alloy elements. It has been proved that f. carbide precipitation in the investigated alloys mainly depends on carbon concentration in martensile. The temperatures of the beginning and end of independent nucleating MC type vanadium carbides precipitation depend not only on carbon concentration in the alloys but also on the footing rate for tempering.