Effect of Ti addition on hardness change during tempering in reduced activation ferritic/martensitic (RAFM) steels

Kim, Byung Hwan; Jang, Jae Hoon; Seol, Woo-Kyung; Moon, Joonoh; Kim, Sung Dae; Lee, Tae‐Ho; Kim, Hyoung Chan; Lee, Chang‐Hoon; Cho, Kyung-Mox

doi:10.1016/j.jnucmat.2018.05.075

Cited by 28 publications

(3 citation statements)

References 17 publications

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“…To study the effect of Ti addition on the MX precipitates, the level of MX precipitation for varying Ti concentrations was estimated by Thermo‐Calc (with the TCFE7 database). For the 0.01Ti alloy, the total fraction of MX (the sum of VN and (Ta, Ti) (C, N) fractions) was predicted as 1.22 × 10 −3 at 750 °C, which is higher than that for RAFM steel without Ti (1.02 × 10 −3 ) . Fraction values of 2.18 × 10 −3 and 3.64 × 10 −3 were observed for the MX precipitates in the 0.05Ti and 0.11Ti alloys, respectively.…”

Section: Resultsmentioning

confidence: 85%

“…Kim et al investigated the effects of the addition of Ti and Ta on the microstructure stability and tensile properties of Eurofer97 (EU’ RAFM) steel tempered at 700 °C for 1.5 h. The addition of Ti to conventional Eurofer97 reference base steel (Fe 9.3 Cr 0.93 W 0.22 V 0.094 Ta 0.1 C) was intended to promote the precipitation of nanosized (Ti, W) C carbides with high resistance to coarsening, leading to a higher yield strength (YS) at 600 °C compared with the reference base steel. Kim et al reported that Ta‐Ti‐Eurofer97 (Fe 8.8 Cr 0.13 Si 0.44 Mn 1.02 W 0.21 V 0.09 Ta 0.014 Ti 0.092 C) contains lath martensite with fine (Ta, Ti) C precipitates that do not dissolve during normalization at 750 °C. It has been suggested that the addition of Ti promotes the precipitation of fine (Ti, W) C or (Ti, Ta) C, thus improving the mechanical properties of steel.…”

Section: Introductionmentioning

confidence: 99%

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Effects of Ti Addition on the Microstructure and Tensile Properties of China Low Activation Martensitic Steel for Nuclear Fusion Reactors

Zhan

Qiu

et al. 2019

steel research int.

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Herein, the effects of Ti, a low activation alloying element, in the range of 0.01–0.11 wt% on the microstructure, mechanical properties, and impact toughness of China low activation martensitic steel are studied. Fine prior austenite grains and some δ‐ferrite phases are observed for alloys with a Ti content of 0.05 and 0.11 wt%, respectively. The 0.05Ti alloy exhibits a higher yield strength (YS) compared with the 0.01Ti and 0.11Ti alloys because of the additional precipitation hardening by the fine MX particles and small grain size. When the samples are tempered at 650 °C, nanosized (Ti, W) C MX carbides with a size of approximately 20 nm precipitate, leading to an increase in the ultimate tensile strength (UTS) and YS of the 0.05Ti alloy. The ductile‐to‐brittle transition temperature (DBTT) decreases when the Ti content increases to 0.05 wt%. However, the DBTT of the 0.11Ti alloy increases with the precipitation of the δ‐ferrite phase. On the basis of the performance of the steels, the optimal Ti content is found to be approximately 0.05 wt% and the optimal tempering temperature is found to be 650 °C.

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Section: Resultsmentioning

confidence: 85%

Section: Introductionmentioning

confidence: 99%

Effects of Ti Addition on the Microstructure and Tensile Properties of China Low Activation Martensitic Steel for Nuclear Fusion Reactors

Zhan

Qiu

et al. 2019

steel research int.

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“…Martensite has heterogeneity in its micromechanical strength and importantly the following consequences on final mechanical properties [6].…”

Section: Introductionmentioning

confidence: 99%

Effect of Holding Time and Cooling Medium on Microstructure and Hardness of AISI 8655 in Hardening Process

Wibisono¹,

Ramadhani²,

Rochiem³

2018

IJOE

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AbstractThe microstructure transformation of AISI 8655, affecting to hardness and impact properties in various hardening processes, has been investigated in this work. AISI 8655 specimens which had been prepared before hardening processes were heated to austenite temperature and held for 30 minutes and 60 minutes then continued by rapid cooling in various medium (air, oil and water). The hardened steel specimens were tested by optical microscope to observe microstructure, brinell test and impact test respectively to measure hardness and impact strength properties. Martensite and bainite were microstructures that appeared after hardening processes. The holding time for 30 minutes gave higher hardness properties than the holding time for 60 minutes. However, the holding time for 60 minutes performed higher impact strength than that for 30 minutes. The highest of hardness was performed by the specimen cooled in water medium at 552 BHN and the highest of impact strength was performed by the specimen cooled in air medium at 7.2 J/mm2.

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Effect of Ta and Ti on Modified Reduced Activation Ferritic/Martensitic Steels with a Thermo‐mechanical Control Process

Zhu

Zhang

Cui

et al. 2020

steel research int.

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Modified reduced activation ferritic/martensitic steels with different amounts of Ta and Ti are fabricated with a thermo‐mechanical control process (TMCP). TMCP greatly enhances the refinement of both the precipitates and the martensite matrix. In addition, an increase in the dislocation density is achieved. The modified steels show excellent comprehensive mechanical properties compared with traditional reduced activation ferritic/martensitic steels. In addition, under the conditions of the TMCP, the effects of Ta and Ti on the microstructure and properties are analyzed. Simply increasing the amounts of Ta and Ti does not increase the phase fraction of MX, which is quite different from that derived from equilibrium thermodynamics theory or the typical hot rolling process for traditional reduced activation ferritic/martensitic steels. Without a high enough nucleation rate for MX, the excess Ta and Ti, which are not consumed by the formation of MX, promotes the formation of proeutectoid ferrite. This decreases the impact on toughness significantly. Herein, preliminary guidance is offered for a comprehensive design with a combination of both composition and rolling processing modification for the production of reduced activation ferritic/martensitic steels.

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Effect of Ti addition on hardness change during tempering in reduced activation ferritic/martensitic (RAFM) steels

Cited by 28 publications

References 17 publications

Effects of Ti Addition on the Microstructure and Tensile Properties of China Low Activation Martensitic Steel for Nuclear Fusion Reactors

Effects of Ti Addition on the Microstructure and Tensile Properties of China Low Activation Martensitic Steel for Nuclear Fusion Reactors

Effect of Holding Time and Cooling Medium on Microstructure and Hardness of AISI 8655 in Hardening Process

Effect of Ta and Ti on Modified Reduced Activation Ferritic/Martensitic Steels with a Thermo‐mechanical Control Process

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