Isothermal treatment influence on nanometer-size carbide precipitation of titanium-bearing low carbon steel

Wang, Tzu-Pin; Kao, Fang-Hsin; Wang, Shing-Hoa; Yang, Jer−Ren; Huang, Ching‐Yuan; Chen, Hsueh-Ren

doi:10.1016/j.matlet.2010.10.022

Cited by 46 publications

(12 citation statements)

References 14 publications

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“…Most early studies [8,[25][26][27] generally emphasized that only interphase precipitation morphology could occur within the ferrite matrix. However, it is worthy to note that not only the present study but also more and more research has demonstrated the coexistence of interphase precipitation and random precipitation [16,[19][20][21][28][29][30][31][32]. The above metallurgical phenomenon is associated with the kinetics of austenite decomposition in different processes, which will be discussed in detail later.…”

Section: Precipitate Morphology Observed By Transmission Electron Micsupporting

confidence: 48%

“…First, ϭϯ in terms of kinetics, the austenite decomposition rate can be accelerated as austenite undergoes heavy deformation, which makes the diffusivity of microalloying elements scarcely comparable to that of the movement velocity of austenite/ferrite interface and leads to the disappearance of the interphase precipitation morphology and formation of supersaturated ferrite grains [28][29][30][31][32]. Second, in terms of thermodynamics, the solubility of microalloying elements in the ferrite matrix decreases as the isothermal holding temperature decreases [33].…”

Section: Verification Of Random Precipitation Morphology Occurring Inmentioning

confidence: 99%

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Control of precipitation morphology in the novel HSLA steel

Chen

et al. 2015

Materials Science and Engineering: A

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Section: Precipitate Morphology Observed By Transmission Electron Micsupporting

confidence: 48%

Section: Verification Of Random Precipitation Morphology Occurring Inmentioning

confidence: 99%

Control of precipitation morphology in the novel HSLA steel

Chen

et al. 2015

Materials Science and Engineering: A

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“…This result is inconsistent with the earlier papers which revealed that carbide precipitates from ferrite obey B-N orientation relationship with the ferrite matrix. [3,[22][23][24][25][26][27][28] The carbide is so fine that it lies within the foil thickness. This leads to the development of a moire´fringe contrast due to the overlapping carbide and ferrite lattices.…”

mentioning

confidence: 99%

“…The main focus in samples A and B is the difference in the contribution of precipitation strengthening on yield strength. There are studies reported in the literature [25,28,33] that relate the carbide precipitation to nanohardness measurements. Figure 11(a) shows the typical nanoindenter morphologies and the elastic load-depth plots calculated by Hertzian elastic contact solution, [34] where the radius of the curvature for the Berkovich indenter is~110 nm and the reduced modulus was 215 GPa.…”

mentioning

confidence: 99%

The Determining Role of Finish Cooling Temperature on the Microstructural Evolution and Precipitation Behavior in an Nb-V-Ti Microalloyed Steel in the Context of Newly Developed Ultrafast Cooling

Wang

Deng

et al. 2016

Metall Mater Trans A

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We have studied here the impact of finish cooling temperature on the microstructural evolution and precipitation behavior in Nb-V-Ti microalloyed steel through thermo-mechanical simulation in the context of newly developed ultrafast cooling system. The microstructural evolution was studied in terms of morphology and crystallography of precipitates using high-resolution transmission electron microscopy. At finish cooling temperature of 933 K and 893 K (660°C and 620°C), the microstructure primarily consisted of polygonal ferrite, together with a small amount of wedge-shaped acicular ferrite and lamellar pearlite, while, at 853 K and 813 K (580°C and 540°C), the microstructure consisted of lath bainite with fine interlath cementite and granular bainite with martensite/ austenite (M/A) constituent. In all the finish cooling temperatures studied, the near-spherical precipitates of size range~2 to 15 nm were randomly dispersed in ferrite and bainite matrix. The carbide precipitates were identified as (Nb,V)C with NaCl-type crystal structure. With a decrease in the finish cooling temperature, the size of the precipitates was decreased, while the number density first increased with a peak at 893 K (620°C) and then decreased. Using Ashby-Orowan model, the contribution of the precipitation strengthening to yield strength was~149 MPa at the finish cooling temperature of 893 K (620°C).In the last few decades, high-strength low-alloy (HSLA) steels have been widely used in buildings, bridges, and ships because of their potential to obtain high strength-toughness combination. [1] Superior mechanical properties were obtained through optimization of alloy design in conjunction with thermo-mechanical processing (TMCP). [2][3][4][5] The improvement in mechanical properties was a consequence of grain refinement together with microstructural control and precipitation strengthening. The carbide-forming elements include titanium and niobium that facilitate grain refinement and contribute to dispersion hardening through carbide precipitation in the matrix. The relative contribution of the microalloying elements is determined by the solubility of carbides in the microstructure. Titanium is beneficial because it combines with nitrogen at relatively high temperature, preventing grain growth, while niobium can effectively retard recovery and recrystallization during hot rolling leading to grain refinement. Moreover, these two elements can precipitate as carbides from the supersaturated ferrite solid solution or precipitate as interphase precipitates during austenite-to-ferrite transformation increasing strength. Vanadium is less effective in grain refinement but contributes to strength via precipitation hardening because of higher solubility in austenite as compared to niobium, leading to precipitation at lower temperature. [6] TMCP involving ultrafast cooling (UFC) technology developed by our laboratory is being currently applied to industrial production, [7][8][9] with the aim to reduce the consumption of alloying elements and make the s...

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“…Titanium microalloyed steels have been extensively studied by metallurgists [2,3]. They also contained Nb, V, and Si [4][5][6].…”

Section: Introductionmentioning

confidence: 99%

Effect of microalloying with molybdenum and boron on the microstructure and mechanical properties of ultra-low-C Ti bearing steel

et al. 2015

Materials Science and Engineering: A

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Isothermal treatment influence on nanometer-size carbide precipitation of titanium-bearing low carbon steel

Cited by 46 publications

References 14 publications

Control of precipitation morphology in the novel HSLA steel

Control of precipitation morphology in the novel HSLA steel

The Determining Role of Finish Cooling Temperature on the Microstructural Evolution and Precipitation Behavior in an Nb-V-Ti Microalloyed Steel in the Context of Newly Developed Ultrafast Cooling

Effect of microalloying with molybdenum and boron on the microstructure and mechanical properties of ultra-low-C Ti bearing steel

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