ZHANG Qiao-ying
,
WANG Xin-hua
钢铁研究学报(英文版)
The influences of casting speed variation on surface fluctuation of the molten steel of mold during continuous casting were investigated with numerical simulation method. It was found that, when the casting speed was evenly decreased from 1.4m/min to 0.6m/min, increases of the surface fluctuation of the molten steel of mold were observed only on time that was at the start of casting speed change. While, in experiment of increasing casting speed evenly from 0.6m/min to 1.4m/min, increases of the surface fluctuation of the molten steel of mold were observed only at the time when the casting speed was stopped to increase after it had been increased to 1.4m/min. For surface fluctuation of the molten steel of mold which was produced during the casting speed evenly increasing or decreasing period and at the time when increasing or decreasing the casting speed at low casting speed level (0.6m/min), the influence of casting speed change was very small. In addition, it was found that, at high casting speed level (1.4m/min), even a little change of casting speed could result in remarkable increase of the surface fluctuation. Thus, at high casting speed, changing casting speed should be avoided or using much slower speed changing rate.
关键词:
YANG Jun
,
WANG Xin-hua
,
JIANG Min
,
WANG Wan-jun
钢铁研究学报(英文版)
The influence of calcium treatment on non-metallic inclusions had been studied when control technology of refining top slag in ladle furnace was used in ultra-low oxygen steelmaking. A sufficient amount aluminium was added to experimental heats for final deoxidizing during BOF tapping, and the refining top slag with strong reducibility, high basicity and high Al2O3 in ladle furnace was used to produce ultra-low oxygen steel and the transformation of non-metallic inclusions in molten steel was compared by calcium treatment and no calcium treatment. The results show that the transformation of Al2O3→MgO·Al2O3 spinel→CaO-MgO-Al2O3 complex inclusions has been completed for aluminum deoxidation products and calcium treatment to molten steel is unnecessary when using the control technology of ladle furnace refining top slag to produce ultra-low oxygen steel, and the complex inclusions are liquid at the temperature of steelmaking and easily removable to obtain very high cleanliness steel by flotation. Furthermore, the problems of nozzle clogging in casting operations do not happen and the remaining oxide inclusions in steel are the relatively lower melting point complex inclusions.
关键词:
ultra-low oxygen
,
top slag
,
deoxidization
,
aluminium
,
oxide inclusion
,
calcium treatment
LI Chong-wei
,
CHENG Guo-guang
,
WANG Xin-hua
,
ZHU Guo-sen
,
CUI Ai-min
钢铁研究学报(英文版)
A mathematical model in present study has been established to investigate the effect of Rheinstahl Heraeus (RH) blow argon mode on the decarburization rate in ultra-low carbon steel refining based on the RH equipment of Shougang Qian′an Iron and Steel Co Ltd (SQISCO). The calculated results show that the increase of argon flowrate promotes the carbon elimination from argon gas bubble surface, molten steel free surface in vacuum as well as splash droplet surface, while reduces that from the interior of liquid steel. It has been found the critical turning point of flowrate ascension is at the 5th minute and the optimum blow argon flowrate in later stage is 2100 L/min in accordance with the 2 stages argon blow mode, which have been confirmed in the commercial production in SQISCO.
关键词:
RH
,
vacuum
,
mathematical model
,
argon flowrate
,
decarburization
YANG Wen
,
CAO Jing
,
WANG Xin-hua
,
XU Zhi-rong
,
YANG Jie
钢铁研究学报(英文版)
The behavior of non-metallic inclusions in LCAK (low carbon aluminum killed) steel produced by BOF (basic oxygen furnace)-LF (ladle furnace) refining-FTSC (flexible thin slab continuous caster) production route was investigated. The results showed that, LF refining for LCAK steel could decrease the wT[O] significantly, and the inclusions were modified by Ca treatment, which prevented nozzle clogging efficiently. However, owing to the unstable casting condition in the earlier stage of casting, a severe reoxidation occurred, accompanied with mold slag entrapment. The transformation of non-metallic inclusions during the steelmaking process was Al2O3→MgO-Al2O3 type inclusion→MgO-Al2O3-CaO type inclusion with a CaS ring, and the mechanism of the transformation was proposed and discussed via thermodynamic and kinetic analysis. Besides, to avoid CaS precipitation, the product of w2[Al]×w3[S] in steel should be less than 2.0×10-10 at 1873 K, which remands higher desulfurization ratio during LF refining.
关键词:
LCAK steel
,
ladle refining
,
FTSC
,
non-metallic inclusion
HUANG Fu-xiang
,
WANG Xin-hua
,
WANG Wan-jun
钢铁研究学报(英文版)
The microstructures of austenitic stainless steel strip were studied using color metallographic method and electron probe micro analysis (EPMA). In the cast strips, there are three kinds of solidification structures: fine cellular dendrite in the surface layer, equiaxed grains in the center and fine dendrite between them. The solidification mode in the surface layer is the primary austenite AF mode because of extremely high cooling rate, with the retained ferrite located around the primary cellular austenite. In the fine dendrite zone, the solidification mode of molten stainless steel changes to FA mode and the residual ferrite with fish-bone morphology is located at the core of the dendrite. The retained ferrite of equiaxed grains in the center is located in the center of broken primary ferrite dendrite with vermicular morphology.
关键词:
strip casting
,
solidification microstructure
,
austenitic stainless steel
,
retained ferrite
常永勤
,
介万奇
,
郭喜平
,
陈福义
,
安卫军
功能材料
研究了ACRT-B法生长的Mn0.1Cd0.9In2Te4晶体中界面的形状和各组元沿轴向的分布规律及其分凝因数.发现结晶界面为椭球形;采用理想配比生长MnxCd1-xIn2Te4晶体,其4种组元并不按(Mn,Cd):In:Te=1:2:4比例结晶,而是要重新分布;通过数学方法处理实验数据得到Mn,Cd和In的分凝因数在α相区分别为1.286、1.9257和0.7294,在β相区则分别为1.12、1.055和0.985.
关键词:
ACRT-B法
,
MnxCd1-x In2Te4
,
界面
,
分凝因数
常永勤
,
安卫军
,
郭喜平
,
介万奇
无机材料学报
采用Bridgman法生长了x为0.1,0.22和0.4的四元稀磁半导体化合物MnxCd1-xIn2Te4晶体.研究了三根晶体中相的形貌、结构、成分和Mn0.1Cd0.9In2Te4晶体中各组元沿轴向和径向的成分分布.晶体生长初始端的组织为α+β+β1,随着生长的进行,形成β相的单相区.在晶锭末端,形成In2Te3类面心立方结构化合物.组分x增大后,MnxCd1-xIn2Te4晶体的吸收边向短波方向移动,禁带宽度则线性增大.磁化率测量结果表明:晶体在高温区的x-1-T曲线服从居里-外斯定律,在低温区(<50K)则表现出顺磁增强现象.
关键词:
MnxCd1-xIn2Te4
,
compositional distribution
,
infrared transmission spectra
,
mag- netic susceptibility
常永勤
,
安卫军
,
郭喜平
,
介万奇
无机材料学报
doi:10.3321/j.issn:1000-324X.2003.02.004
采用Bridgman法生长了x为0.1,0.22和0.4的四元稀磁半导体化合物MnxCd1-xIn2Te4晶体.研究了三根晶体中相的形貌、结构、成分和Mno.1Cd0.9In2Te4晶体中各组元沿轴向和径向的成分分布.晶体生长初始端的组织为α+β+β1,随着生长的进行,形成β相的单相区.在晶锭末端,形成In2Te3类面心立方结构化合物.组分x增大后,MnxCd1-xIn2Te4晶体的吸收边向短波方向移动,禁带宽度则线性增大.磁化率测量结果表明:晶体在高温区的x-1-T曲线服从居里一外斯定律,在低温区(＜50K)则表现出顺磁增强现象.
关键词:
MnxCd1-xIn2Te4
,
成分偏析
,
红外透射光谱
,
磁化率
常永勤
,
安卫军
,
郭喜平
,
介万奇
功能材料
采用Bridgman法生长四元稀磁化合物半导体Mn0.22Cd0.78In2Te4晶体.当晶体生长到预定长度时,淬火得到固液界面.采用光学显微镜、扫描电镜、X射线衍射仪、ISIS能谱仪以及Leica定量金相分析仪研究了晶体中出现的界面形态、相的形貌和数量以及沿生长方向的相析出规律,并进行了相成分分析.研究发现,淬火得到的Mn0.22 Cd0.78In2Te4晶体中存在两个界面,其中一个为固液相变界面,另一个为由α+β两相区发展到单相β区时的转变界面,二者相对于生长初始端均为凹形;α+β两相区中,β相以条状、花状和近似圆片状形式存在,其中条状β相多分布在晶界处;越接近生长初始端,花状和近似圆片状β相越小,条状β相越细,它们的含量越少;X射线衍射图谱表明,β相为黄铜矿结构,α相为面心立方结构.
关键词:
MnxCd1-xIn2Te4
,
相变界面
,
β相
,
X射线衍射图谱
