Examples of the evolution of materials for nuclear applications: metallurgical improvement of 16MND5 steel and new technologies for manufacturing heavy components

Bocquet, P.; Cheviet, A.; Dumont, R.

doi:10.1016/0029-5493(94)90191-0

Cited by 6 publications

(4 citation statements)

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“…It was found that the weakening of the prior austenite grain boundaries in such cases was originated in the course of finishing forging and subsequent cooling or primary heat treatment of the forged piece, before the final heat treatment. Intergranular weakening of the prior austenite grains boundaries has been repeatedly observed due to the presence of cracks in finished heavy forgings made of CrNiMo structural steels with a microstructure of tempered bainite [1][2][3][4][5]. Cracks in segregation zones start to appear at the stage of the primary cooling of forgings due to the effect of superposition of thermal and transformation stresses and to the interaction with hydrogen.…”

Section: Introductionmentioning

confidence: 99%

Influence of Annealing Temperature and Time on the Mechanical Properties of Selected Steels for Heavy Forgings

Horník

Zuna

Málek

et al. 2015

KEM

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Two types of steels used for production of heavy forgings were selected for the experimental evaluation of the effect of long time dwell at elevated temperatures and cooling during heat treatment on their mechanical properties in order avoid the possibility of grain boundary embrittlement. Samples from evaluated steels 26NiCrMoV14-5 and 22CrNiMoWV8-8 were austenitized for 2 hours at temperature of 1200°C and oil quenched. Subsequently the annealing at temperatures (200 - 700)°C for 1 hour and 100 hours was applied. Selected mechanical properties, especially hardness and impact energy, were monitored. It was found that for steels 26NiCrMoV14‑5 and 22CrMoNiWV8-8 exist the temperature intervals (300 - 400)°C and (500 ‑ 600)°C respectively with the possible potential for toughness decreasing.

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Section: Introductionmentioning

confidence: 99%

Influence of Annealing Temperature and Time on the Mechanical Properties of Selected Steels for Heavy Forgings

Horník

Zuna

Málek

et al. 2015

KEM

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“…The problematic discussed in this paper is a part of complex research in area of production of heavy forgings. The manufacturing process of heavy forgings is rather complicated with numerous of specifics with requirement on high quality of the final product [1]. There are numerous of potential defects, which can lead to an inappropriate product quality.…”

Section: Introductionmentioning

confidence: 99%

Kinetics of Austenite Recrystallization of Selected Steels Used for Heavy Forgings

Horník

Zuna

Málek

et al. 2014

MSF

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The kinetics of austenite recrystallization was evaluated in range of typical forging temperatures (850 - 1250) °C. The steels SA-508 and 3.5Ni-1.5Cr were compared. The laboratory one step deformation was applied. The effect of selected chemical elements in evaluated steels on grain growth and recrystallization kinetics of austenite and precipitation was monitored using metallographic methods. The retarding of static recrystallization was proved and no abnormal grain coarsening at defined condition was observed.

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“…However, studies of the effect of the alloying element on the mechanical properties have yet to be completed. Since the variation of grain size and alloying elements can affect the mechanical properties of materials at the same time, [14,15,16] it is crucial to separate the effects of the alloying elements and the grain size by fixing the grain size of the materials in order to isolate the effect of the alloying elements. Even when low-alloy steels with excellent mechanical properties are developed, their mechanical properties may deteriorate after welding, which is unavoidable in actual use.…”

Section: Introductionmentioning

confidence: 99%

“…[6,7,8] The Mn-Mo-Ni low-alloy steels used for nuclear reactor pressure vessels have been continuously developed to establish safe operation and to extend service life. [8][9][10][11][12][13][14][15][16] The primary methods used to improve their mechanical properties are grain refinement and the control of alloying elements. Grain refinement can be achieved by grain-boundary pinning with aluminum nitrides or by controlling the austenitization temperature and quenching rate.…”

Section: Introductionmentioning

confidence: 99%

Effects of alloying elements on fracture toughness in the transition temperature region of base metals and simulated heat-affected zones of Mn-Mo-Ni low-alloy steels

Kim

Lee

et al. 2004

Metall Mater Trans A

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This study is concerned with the effects of alloying elements on fracture toughness in the transition temperature region of base metals and heat-affected zones (HAZs) of Mn-Mo-Ni low-alloy steels. Three kinds of steels whose compositions were varied from the composition specification of SA 508 steel (grade 3) were fabricated by vacuum-induction melting and heat treatment, and their fracture toughness was examined using an ASTM E1921 standard test method. In the steels that have decreased C and increased Mo and Ni content, the number of fine M 2 C carbides was greatly increased and the number of coarse M 3 C carbides was decreased, thereby leading to the simultaneous improvement of tensile properties and fracture toughness. Brittle martensite-austenite (M-A) constituents were also formed in these steels during cooling, but did not deteriorate fracture toughness because they were decomposed to ferrite and fine carbides after tempering. Their simulated HAZs also had sufficient impact toughness after postweld heat treatment. These findings indicated that the reduction in C content to inhibit the formation of coarse cementite and to improve toughness and the increase in Mo and Ni to prevent the reduction in hardenability and to precipitate fine M 2 C carbides were useful ways to improve simultaneously the tensile and fracture properties of the HAZs as well as the base metals.

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Examples of the evolution of materials for nuclear applications: metallurgical improvement of 16MND5 steel and new technologies for manufacturing heavy components

Cited by 6 publications

References 0 publications

Influence of Annealing Temperature and Time on the Mechanical Properties of Selected Steels for Heavy Forgings

Influence of Annealing Temperature and Time on the Mechanical Properties of Selected Steels for Heavy Forgings

Kinetics of Austenite Recrystallization of Selected Steels Used for Heavy Forgings

Effects of alloying elements on fracture toughness in the transition temperature region of base metals and simulated heat-affected zones of Mn-Mo-Ni low-alloy steels

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