WANG Qiang
,
WU Ye-ming
,
QIU Sheng-tao
,
ZHAO Pei
钢铁研究学报(英文版)
A computational model of thermal behavior of the top-surface slag layers in continuous casting mold was applied to interpret the thermal insulation of mold powder. The temperature drop of liquid steel caused by heat removal at the interface of molten steel and slag in mold was proposed to evaluate the thermal insulation of mold slag. The calculation results show that slag consumption is one of important factor influencing the temperature drop, while the casting speed has no obvious effect on it. With the increase of slag consumption, the temperature drop is increased.
关键词:
thermal insulation
,
temperature distribution
,
heat flux
,
temperature drop
XIANG Li
,
YUE Erbin
,
FAN Dingdong
,
QIU Shengtao
,
ZHAO Pei
钢铁研究学报(英文版)
Combining with the study of analogue experiments and test analysis, the kinetics of precipitation and growth of AlN and MnS in nonoriented electrical steel produced by the CSP process is calculated. The results show that the precipitate phase particles of AlN and MnS in typical nonoriented electrical steel grades produced by the CSP process have grown to some extent in the soaking stage, but the precipitation contents are less than 20% of the total contents of nitride and sulfide. The precipitate phase particles of AlN and MnS have precipitated almost after the hot rolling process. The precipitation contents are more than 80% of the total contents of nitride and sulfide, but it is very late for the precipitate phase particles to grow at the end of the hot rolling process.
关键词:
CSP;nonoriented electrical steel;calculation;AlN precipitation;MnS precipitation
SHI Caixia
,
CHENG Guoguang
,
LI Zhanjun
,
ZHAO Pei
钢铁研究学报(英文版)
The thermodynamics of TiN precipitation in liquid steel of 430 ferrite stainless steel has been calculated to find out the condition of TiN precipitation during the initial solidification stage. The difference in the solidification structure of 430 ferrite stainless steel has been discussed through comparative tests of vacuum induction furnace melting with different contents of Ti. It has been found that the equiaxed grain proportion can be increased from 20% to 69% as the content of Ti from 01% up to 04%. The size of the TiN particles precipitated is 1-3 μm and the number of TiN particles is about (200-300)/μm2. It is found that the effect of using TiN to refine the solidification structure has been confirmed under the strict process condition used for 430 ferrite stainless steel.
关键词:
titanium nitride (TiN);solidification;thermodynamics;430 ferrite stainless steel
LI Pei-song
,
LU Jun-hui
,
QIU Sheng-tao
,
WANG Zhong-ying
,
ZHAO Pei
钢铁研究学报(英文版)
A circular seam cooling nozzle and its online control system have been developed to reduce the center segregation in high carbon steel billets by decreasing the superheat of the molten steel and improving the equiaxed crystal ratio based on the numerical results. An industrial experiment has been carried out on a 150 mm×150 mm caster to investigate the effect of the circular seam cooling nozzle on the superheat removal of the molten steel. The results show that the circular seam cooling nozzle can be used to control the casting temperature in a closed loop control system. The online control system can be effectively adapted to the variation of operating parameters. The casting lasts about 4 h and about 400 t steel is successfully produced in a continuous operation. The removal of about 14 ℃ superheat and the improvement of approximate 10% equiaxed crystal ratio can be achieved by the newly developed circular seam cooling nozzle.
关键词:
circular seam cooling nozzle
,
high equiaxed crystal ratio
,
billet
,
low superheat
ZHAO Dingguo
,
GUO Peimin
,
ZHAO Pei
钢铁研究学报(英文版)
According to the ion and molecule coexistence theory, the activity model of FeSiB ternary system was established, and the influence of ratio xSi/xFe, boron content and temperature, etc on the activity of the melt compound was investigated. The results show that the FeB activity is high in the liquid iron, when xSi/xFe is 05; the activity of boron increases with increasing the boron content for different contents of xFe and xSi, and the activity of boron at the ratio xFe=04 is about one order of magnitude higher than that for the xFe=08; The activities of the melt compound were also affected by temperature, but the influencing extent was little. The equal activity diagrams of silicon and boron were drawn for the first time according to the model results.
关键词:
activity
,
metallic melt
,
ion and molecule coexistence model
,
equal activity diagram
PANG Jian-ming
,
GUO Pei-min
,
ZHAO Pei
钢铁研究学报(英文版)
The reduction-degree of the sample increases and the utilization ratio of gas decreases when the reaction lasts longer time, which indicates that the reaction is faster at the beginning of reduction, while it becomes slower in subsequent process. The higher the reaction temperature, the higher the utilization ratio of gas and the reduction-degree are, but the difference of utilization ratio among the different temperatures becomes smaller with time. The utilization ratio of gas can reach about 8% and the reduction-degree is 80% for 20 min reduction at 850 ℃, indicating that the reduction reaction by CO is very fast at high temperature. The higher the reaction temperature, the higher the apparent reaction rate constant is, but the difference of apparent reaction rate constant among the different temperatures becomes bigger. The apparent activation energy is about 5911 kJ/mol in the fluidized bed experiment. The increase of reduction-degree with gas velocity shows quite good linearity, indicating that at high temperature even higher velocity of reducing gas can be used to improve the productivity of reactor when CO is used as reducing gas. With the increase of charge height, the metallization ratio and the reduction-degree decrease, but the utilization ratio of gas increases.
关键词:
CO
,
fluidized bed
,
fine powder
,
iron ore
,
reduction-degree
