TY - JOUR
T1 - 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
AU - Li, Xiaolin
AU - Wang, Zhaodong
AU - Deng, Xiangtao
AU - Wang, Guodong
AU - Misra, R. D.K.
N1 - Publisher Copyright:
© 2016, The Minerals, Metals & Materials Society and ASM International.
PY - 2016/5/1
Y1 - 2016/5/1
N2 - 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).
AB - 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).
UR - http://www.scopus.com/inward/record.url?scp=84961162594&partnerID=8YFLogxK
U2 - 10.1007/s11661-016-3424-8
DO - 10.1007/s11661-016-3424-8
M3 - 文章
AN - SCOPUS:84961162594
SN - 1073-5623
VL - 47
SP - 1929
EP - 1938
JO - Metallurgical and Materials Transactions A: Physical Metallurgy and Materials Science
JF - Metallurgical and Materials Transactions A: Physical Metallurgy and Materials Science
IS - 5
ER -