XIE Zhi-xiong
,
GAO Hai-yan
,
WANG Jun
,
YU Yan
,
FANG Yuan
,
SUN Bao-de
钢铁研究学报(英文版)
The static recrystallization kinetics of low-carbon steel cast strip was investigated by means of interrupted hot tensile tests. As-cast strip was reheated and soaked and its austenite grain size was similar to the width level of the as-cast columnar structure. The tests were carried out on Gleeble-3500 thermomechanical simulator. The deformation temperature is in the range of 800 to 1200 ℃ with strain rate of 001 to 1 s-1. The prestrain is fixed at 004 to 012, and the inter-hit delay time varies from 1 to 3000 s. Effect of deformation conditions and initial microstructure on static recrystallization behavior was investigated. The activation energy (Qsrx) and Avrami exponent (n) of static recrystallization were determined to have 241 kJ/mol and 054 respectively by linear regression of the experimental results. A kinetics model was proposed to describe the static recrystallization kinetics in low-carbon steel cast strip. The predicted softening fractions are in good agreement with the experimental results, indicating that the proposed equations can give an accurate estimate of the softening behaviors for the low-carbon steel cast strip.
关键词:
Static recrystallization
HUANG Fuxiang
,
WANG Xinhua
,
ZHANG Jiongming
,
JI Chenxi
,
FANG Yuan
,
YU Yan
钢铁研究学报(英文版)
The solidification process of AISI 304 stainless steel during cooling at a rate of 005 K/s has been observed in situ using a confocal scanning laser microscope (CSLM). The results show that the δ phase appeared first in liquid steel, as the temperature decreased, the γ phase precipitated prior at δgrain boundary at 1 4522 ℃, the liquid steel disappeared at 1 4313 ℃, and then the γ phase precipitated on the δ ferrite. Based on the ScheilGulliver solidification model, the solidification processes of AISI 304 stainless steel are simulated using the Scheil model in ThermoCalc, and the simulation results agree well with the results observed in the experiment.
关键词:
stainless steel;confocal scanning laser microscope;strip casting;ThermoCalc
ZHANG Wei
,
YU Yan
,
FANG Yuan
,
LI Jian-guo
钢铁研究学报(英文版)
For many rapid or near-rapid solidification processes, the interfacial heat transfer between the melt and the substrate is a key issue on the cooling and solidification rate of castings. For the purpose of controlling and adjusting of the interfacial thermal resistance, the effects of C/BN, Zn and organic coatings on the instantaneous interfacial heat flux and the solidified structure of AISI304 stainless steel solidification on copper substrate have been investigated by using an experimental simulator. The results show that C/BN coatings can improve the uniformity of heat flux and solidified structure; Zn coating can increase the heat flux and solidification rate in the growth stage of the solidified shell; organic coating will decrease the heat flux and the solidification rate and make re-melted structure on the surface of the solidified shell.
关键词:
near rapid solidification
,
interfacial heat transfer
,
coating
