Microstructural evolution and mechanical properties of heat affected zones for 9Cr2WVTa steels with different carbon contents

Wang, Jian; Lu, Shanping; Dong, Wenchao; Li, Dianzhong; Liu, Rong

doi:10.1016/j.matdes.2014.08.018

Cited by 34 publications

(3 citation statements)

References 27 publications

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“…Also, the crack sensitivity increased with the increasing of carbon content. 6) So, in order to guarantee weldability, the carbon content of the steel was always kept low. Meanwhile, Cu was generally added into the steel to make up for the strength loss caused by carbon reduction.…”

Section: Introductionmentioning

confidence: 99%

The Role of Cu Addition in Microstructural Characteristics and Mechanical Properties in Submerged Arc Welded Joint of Low Carbon Low Alloy Steel

Feng

Yang

et al. 2022

Mater. Trans.

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A good strength-toughness combination is difficult to be obtained in welded joint of low carbon low alloy steel. In this work, a new idea was proposed to improve the strength and toughness of welded joint by strengthening effect of Cu precipitation and toughening effect of retained austenite. The results show that a multiphase microstructure consisting of ferrite, martensite-austenite island, retained austenite as well as precipitates was obtained in welded metal of Cu-free and Cu-containing steel, while the retained austenite and precipitates were found in fine grained heat affected zone (FGHAZ) and coarse grained HAZ (CGHAZ). It is noted that Cu addition changed the ferrite from polygonal-like to acicular-like, increased amount of retained austenite and promoted the Cu-rich precipitates. Accordingly, a better combination of strength, ductility and toughness was achieved in welded joint of Cu-containing steel. Cu-rich precipitates and strain-induced martensitic transformation of retained austenite maintained high strength in welded joint. Meanwhile, high toughness was ascribed to strain-induced martensitic transformation of retained austenite, acicular ferrite and high angle grain boundary.

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Section: Introductionmentioning

confidence: 99%

The Role of Cu Addition in Microstructural Characteristics and Mechanical Properties in Submerged Arc Welded Joint of Low Carbon Low Alloy Steel

Feng

Yang

et al. 2022

Mater. Trans.

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“…In order to improve the corrosion/irradiation resistance, C and Si elements are added in high-chromium heat-resistant steels. However, high contents of alloying elements, such as Cr, C, Mn and Si, increase the hardening tendency of steel and eventually result in poor weldability, particularly the poor toughness of HAZs [4][5][6][7][8]. The heat-affected zone (HAZ) of high-chromium heat-resistant steel was usually believed to be the weakest region in a welded joint in respect of impact toughness, because of the quenched martensite and even δ-phase [9][10][11][12].…”

Section: Introductionmentioning

confidence: 99%

Impact Toughness of Heat-Affected Zones of 11Cr Heat-Resistant Steels

Jianxin

et al. 2020

Acta Metall. Sin. (Engl. Lett.)

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Aiming at the requirements of structural steel in Gen-IV nuclear reactor, the high-chromium martensitic heat-resistant steels containing 10-12% chromium were developed. The toughness of heat-affected zones (HAZs) is one of the important factors for evaluating the weldability of steels. In this paper, the simulated HAZs were fabricated using tempered SIMP steels. The effects of microstructures on the impact toughness of materials were analyzed using Vickers hardness tester, optical microscope, transmission electron microscope. Experimental results demonstrated that the HAZs of weldment were poor in toughness, much lower than that of the base metal. However, after experiencing post-weld heat treatment, the toughness of the HAZs increased greatly. The toughness became better in terms of CG-HAZ, FG-HAZ and IC-HAZ for the two steels, regardless of as-welded or after PWHT. Compared with SIMP7 steel, chemical compositions, such as C, Si, Mn and Cr, were adjusted to a lower content; the toughness of base metal and simulated HAZs was better in the case of SIMP11. The conjunct roles of dislocation density and carbon contents retained in the martensite led to poor impact toughness of the aswelded HAZs, because dislocations and carbon atoms affected the inner stresses within lattices.

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“…For instance, the estimated key irradiation parameters of the first wall in DEMO with a fusion power of 2-2.5 GW in operation include a neutron wall loading of < 2 MW/m 2 and a neutron fluence of 5-8 MW-y/m 2 , which would amount to an accumulated dose of 25-30 dpa per year in steels [1].Reduced activation ferritic/martensitic (RAFM) steels based on low-activation elements (e.g., Fe, V, Cr, Mn, Ta, W, Si, C) are currently one of the most promising structural materials for first wall and breeding-blanket applications in fusion reactors [2][3][4][5]. They were selected for the test blanket module for ITER [5][6][7][8] and are considered as a primary candidate structural material for DEMO [9,10]. RAFM steels are essentially modifications of the body-centered cubic (bcc), Fe-rich, Fe-Cr binary alloys and contain minor concentrations of low-activation elements, such as manganese to improve the abrasion and wear resistance as well as tensile properties [11], tungsten and vanadium to maintain a low activation level and to resist irradiation embrittlement [12,13].…”

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confidence: 99%

Understanding the mechanical properties of reduced activation steels

Schönecker

et al. 2018

Materials & Design

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Reduced activation ferritic/martensitic (RAFM) steels are structural materials with potential application in Generation-IV fission and fusion reactors. We use density-functional theory to scrutinize the micro-mechanical properties of the main alloy phases of three RAFM steels based on the bodycentered cubic FeCrWVMn solid solution. We assess the lattice parameters and elastic properties of ferromagnetic α-Fe and Fe 91 Cr 9 , which are the main building blocks of the RAFM steels, and present a detailed analysis of the calculated alloying effects of V, Cr, Mn, and W on the mechanical properties of Fe 91 Cr 9 . The composition dependence of the elastic parameters is decomposed into electronic and volumetric contributions and studied for alloying levels that cover the typical intervals in RAFM steels. A linear superposition of the individual solute effects on the properties of Fe 91 Cr 9 is shown to provide an excellent approximation for the ab initio values obtained for the RAFM steels. The intrinsic ductility is evaluated through Rice's phenomenological theory using the surface and unstable stacking fault energies, and the predictions are contrasted with those obtained by empirical criteria. Alloying with V or W is found to enhance the ductility, whereas additional Cr or Mn turns the RAFM base alloys more brittle.capable of withstanding a high neutron fluence is one of the most critical challenges in fusion technology research. For instance, the estimated key irradiation parameters of the first wall in DEMO with a fusion power of 2-2.5 GW in operation include a neutron wall loading of < 2 MW/m 2 and a neutron fluence of 5-8 MW-y/m 2 , which would amount to an accumulated dose of 25-30 dpa per year in steels [1].Reduced activation ferritic/martensitic (RAFM) steels based on low-activation elements (e.g., Fe, V, Cr, Mn, Ta, W, Si, C) are currently one of the most promising structural materials for first wall and breeding-blanket applications in fusion reactors [2][3][4][5]. They were selected for the test blanket module for ITER [5][6][7][8] and are considered as a primary candidate structural material for DEMO [9,10]. RAFM steels are essentially modifications of the body-centered cubic (bcc), Fe-rich, Fe-Cr binary alloys and contain minor concentrations of low-activation elements, such as manganese to improve the abrasion and wear resistance as well as tensile properties [11], tungsten and vanadium to maintain a low activation level and to resist irradiation embrittlement [12,13]. The composition of the main alloying elements lies in the range (wt.%) Fe-(7.5-12)Cr-(1.0-2.2)W-(0.15-0.25)V-(0.05-0.6)Mn [14,15].Recent experimental progress has mainly focused on the fabrication, manufacturing, mechanical properties (precipitation behavior, fracture toughness, creep, fatigue, and thermal aging), effects of irradiation, and corrosion analysis of RAFM steels [14,[16][17][18][19][20]. Irradiation damage on the microstructure and mechanical properties, including irradiation hardening and embrittlement by neutrons and helium,...

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Microstructural evolution and mechanical properties of heat affected zones for 9Cr2WVTa steels with different carbon contents

Cited by 34 publications

References 27 publications

The Role of Cu Addition in Microstructural Characteristics and Mechanical Properties in Submerged Arc Welded Joint of Low Carbon Low Alloy Steel

The Role of Cu Addition in Microstructural Characteristics and Mechanical Properties in Submerged Arc Welded Joint of Low Carbon Low Alloy Steel

Impact Toughness of Heat-Affected Zones of 11Cr Heat-Resistant Steels

Understanding the mechanical properties of reduced activation steels

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