Embrittlement Due to the High Temperature Solution Annealing in 18% Ni Maraging Steels

Hosomi, Koji; Ashida, Yoshio; Hato, Hiroshi; Ishihara, Kazunori

doi:10.2355/tetsutohagane1955.61.7_1012

Cited by 10 publications

(3 citation statements)

References 8 publications

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“…Goldberg [6] observed that the PAG contained irregular shaped bands or stringers before recrystallisation, whereas the PAG was full of blocky (massive) martensite after recrystallisation. In the present study, the change of morphology agrees well with previous reports [5,6]. It is evident that the re-dissolution of the intermetallic compounds and recrystallisation, can have an important influence on the martensitic transformation point of C250.…”

Section: Discussionsupporting

confidence: 93%

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Effect of Solution Treatment Time on Microstructure and Martensitic Transformation Point of C250 Steel

Hua

Wei

Peng

et al. 2011

AMR

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The morphology of microstructure and PAG was observed by means of LEICA DMIRM metallurgical microscope, the phase was measured by D8 ADVANCE X-ray diffractometer (XRD), and the martensitic transformation point is tested on DIL805A dilatometer after ST. The results show that the PAG size of C250 steel has not a clear growth. The recrystallisation has the priority of nucleation in the PAG boundary. The morphology of martensite presents irregular bans and stringers before recrystallisation, whereas presents blocky thereafter. The intermetallic compounds re-dissolve by ST. With the prolonged of ST time, the Ms point increases before recrystallisation, decreases thereafter; the Mf point does not have a clear change.

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Section: Discussionsupporting

confidence: 93%

“…Hosomi etal. [5] recognized that the stringer martensite was only developed in the range from A f to recrystallisation temperature. Goldberg [6] observed that the PAG contained irregular shaped bands or stringers before recrystallisation, whereas the PAG was full of blocky (massive) martensite after recrystallisation.…”

Section: Discussionmentioning

confidence: 99%

Effect of Solution Treatment Time on Microstructure and Martensitic Transformation Point of C250 Steel

Hua

Wei

Peng

et al. 2011

AMR

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“…[4][5][6] For improvement in these properties, refinement of austenitic grain is useful.3,6,7~ Further intended grain refinement is required to obtain an excellent combination of toughness and ductility at a high strength level, because the higher the strength, becomes the smaller the critical grain size above which tensile specimens fracture within the elastic limit without showing reduction of area.…”

Section: Introductionmentioning

confidence: 99%

Effect of Alloying Elements on Strengthening and Toughening of Maraging Steels through α'_??_γ Cyclic Heat Treatment

1982

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SynopsisThe effect of addition of 5 Co, 1 Ti or 1-' 2 Mo (percent by weight) to steel has been studied in order to produce higher strength maraging steels. Grain refinement through a' ± r cyclic heat treatment was applied and the microstructures and mechanical properties were investigated in comparison with the results of conventional solution heat treatment. Initial grain size prior to cyclic treatment was coarse (0.6 mm) because of complete solution treatment at high temperature. The addition of each alloying element increased strength level for base steel from 2 550 to 2 750 MPa and lowered fracture toughness irrespective of the kind of alloying elements and the heat treatment. The results of conventional solution treatment showed that there existed little effect of alloying elements on grain size, and the ductility decreased monotonously according to the increase in strength level. In the case of cyclic treatment, the addition of Co promoted grain refinement (7 pm) and thus yielded the same ductility as that of the base steel even at higher strength level, whereas the addition of Ti and Mo suppressed refinement (11 20 ~Cm) leading to marked decrease in ductility. The cyclic treatment was thus found to be more useful in obtaining good combination of strength, ductility and toughness than the conventional solution treatment, particularly, in the steel with high Co.

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Effects of solution treatment temperatures on microstructure, tensile and fracture properties of Co‐free 18 Ni maraging steel

et al. 1994

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The study presents the influences of solution treatment temperatures (S.T.T.) on microstructure, tensile and fracture properties of 18 Ni cobalt free maraging steel. The results are thoroughly discussed in light of the prevailing microstructural conditions as revealed by optical and transmission electron microscopy, and detailed scanning electron fractography. It is found that tensile strength in both unaged and aged conditions is independent of solutioning temperature and, consequently, grain size. However, the tensile ductility, CVN and Kie in aged condition get severely affected with the increase in S.T.T. because of a change occurring in the martensitic lath morphology from blocky to stringer type. This transition in the martensitic morphology starts at the prior austenitic grain size of 35-40 µm and is completed at 120-130µm. Solutioning at 1323 K followed by air cooling, however, results in thermal embrittlement of the steel due to grain boundary precipitation of TiCN. The prior austenitic grain size in this reaction plays only an indirect role. Based on these results, it has been suggested that the existing controversies on the effect of S.T.T. grain size on tensile ductility and fracture behaviour of maraging steels can be rationalized if the changes in martensitic lath morphology are considered as an important variable. EinfluB der Temperaturen beim LosungsglOhen auf Mikrostruktur und Festigkeitseigenschaften eines martensitaushartenden Stahls. Die vorliegende Studie berichtet Ober den EinfluB der LosungsglOhtemperaturen auf Mikrostruktur und Festigkeitseigenschaften eines martensitaushartenden, Co-freien Stahls mit 18 % Ni. Die Ergebnisse werden im Hinblick auf die vorherrschenden Mikrostrukturbedingungen diskutiert, wie sie Lichtmikroskopie, TEM und detaillierte Bruchuntersuchungen mit REM widergeben. Es zeigt sich, daB die Zugfestigkeit -unabhangig von einer Alterungsbehandlung -nicht von der LosungsglOhtemperatur -und folglich der KorngroBe -abhangt. Dagegen wird die Zahigkeit der gealterten Probe von steigenden Temperaturen deutlich beeinfluBt. Der Grund hierfOr liegt in einer Veranderung der Morphologie der Martensitlatten von Blockzu Zeilenanordnung. Dieser Wandel beginnt bei einer KorngroBe des ehemaligen Austenits von 35-40 µm und endet bei 120-130 µm. LosungsglOhen bei 1323 K mit nachfolgender LuftabkOhlung !Ohrt zu thermischer Versprodung des Stahls aufgrund der Korngrenzenausscheidung von TiCN. Die KorngroBe des ehemaligen Austenits spiel! in diesem Zusammenhang nur eine indirekte Rolle. Basierend auf diesen Ergebnissen konnen die bestehenden Kontroversen hinsichtlich des Einflusses der KorngroBe nach einer LosungsglOhbehandlung auf Zahigkeit und Bruchverhalten martensitaushartender Stahle nur dann vernOnfig erklart werden, wenn die Veranderung der Martensitlattenmorphologie als eine wichtige Variable angesehen wird.

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Embrittlement Due to the High Temperature Solution Annealing in 18% Ni Maraging Steels

Cited by 10 publications

References 8 publications

Effect of Solution Treatment Time on Microstructure and Martensitic Transformation Point of C250 Steel

Effect of Solution Treatment Time on Microstructure and Martensitic Transformation Point of C250 Steel

Effect of Alloying Elements on Strengthening and Toughening of Maraging Steels through α'_??_γ Cyclic Heat Treatment

Effects of solution treatment temperatures on microstructure, tensile and fracture properties of Co‐free 18 Ni maraging steel

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