Kinetic study on deep dephosphorization treatment of liquid steel by BaO-based fluxes

Laboratory study was carried out on deep dephosphorization of liquid steel by BaO-based fluxes at 1600℃ to achieve ultra low phosphorus level in the steel. A dynamic model of dephosphorization of liquid steel by BaO-based fluxes was established. According to the model, the controlling step of dephosphorization by BaO-based fluxes was the mass-transfer of phosphorus in steel phase under the condition of low phosphorus liquid steel. It is estimated that the apparent rate constant of dephosphorization by BaO-based fluxes was 0.4×10-3-8.2×10-3 g/(cm2·s) and the mass-transfer coefficient of phosphorus in bulk steel was 0.025-0.04 cm/s.     

不锈钢液氧化脱磷保铬的实验研究

本文在用ＢａＯ基渣系对不锈钢氧化脱磷平衡实验的基础上，研究不锈钢液脱磷过程中铬的氧化行为，以及氧位、温度和渣系组成对脱磷保铬的影响。     

LD-BAr-CC工艺生产低碳铝镇静钢纯净度研究

研究武汉钢铁股份有限公司炼钢总厂四分厂LD-BAr-CC工艺条件下生产的低碳铝镇静钢的纯净度,分析各工艺阶段钢中显微夹杂、大型夹杂以及全氧、氮含量的变化情况。结果表明,在该厂现行工艺条件下,采用吹氩工艺可明显降低钢中夹杂物含量和全氧含量,全氧含量从精炼前的109.30×10-6降至30.75×10-6。各工序中钢的显微夹杂物主要为Al2O3和SiO2,这是脱氧产物和钢液二次氧化产物在钢中的残留物;大型夹杂物主要是Al2O3、SiO2以及硅铝酸盐等复合夹杂,与浮渣的卷入有很大关系。     

炼钢工艺和成分体系对B50A1300硅钢铁损的影响

以低牌号B50A1300硅钢为研究对象,探讨了精炼RH吹氧量、w[Mn]2/w[Si]比值、FeAl预脱氧效果以及连铸钢水镇静时间等对B50A1300硅钢铁损的影响。结果表明,当精炼RH过程吹氧量大于160 Nm3时,钢的铁损迅速劣化;合适的钢成分体系是将w[Mn]2/w[Si]比值严格地控制在0.5以内;最佳的FeAl、FeSi脱氧效果是将FeAl、FeSi脱氧后钢水含氧量分别控制在140×10-4%左右和90×10^-4%-140×10^-4%。     

Effects of [S] and T[O] on strength and toughness of high purification low alloy steel plates

The effect of [S] on strength and toughness of low alloy steel plates in which sum of [P], [N], T[O] is less than 8x10 5 and the effect of T[O] on strength and toughness of the steel plates in which sum of [S], [P], [N] is less than 7x10~5 were investigated. It is found that the strength of the steel plates decreases with increasing [S] content when [S] is less than 4x10~5. When [S] varies within the range of 4×10~(-5)-1.2×10~(-4), [S] has no significant effect on strength of the steel. The strength of the steel plates increases with increasing T[O] content when T[O] is less than 30×10~(-6), but decreases with increasing T[O] when T[O] is more than 3×10~(-5). The difference between the LETT in plate length direction and LETT in width direction decreases with decreasing [S] content. However, even when [S] is decreased to 9×10~(-6), the difference of the LETT is still 16℃. When T[O] varies between 1.8×10~(-5) and 5.2×10~(-5), the low temperature impact toughness of the steel plates slowly decrease     

开发应用钢包渣还原处理技术提高钢的纯净度

通过对钢水二次氧化的分析,揭示了钢包渣对钢水二次氧化的主要作用.钢包渣还原处理技术的开发及应用,为降低钢水氧含量、降低板坯夹杂物进而提高产品质量起到了重要作用,同时促进了钢水进一步脱硫.     

超声波强化酸浸高磷铁矿石除磷试验研究

针对某焙烧-磁选后的高磷铁精矿(铁品位54.92%,磷含量0.83%),采用超声波强化硫酸浸出其中的磷。试验结果表明:随着超声时间的延长,除磷率逐渐降低,当超声时间为60min时,矿石的铁品位有一定波动,但比原来都有一定程度的提高,可达到58%以上,而铁回收率会随着超声时间的延长呈下降趋势,但都在92%以上;随着矿浆浓度的增加,浸出后矿石中的磷含量也逐渐增加,当矿浆浓度低于6%时,超声波除磷效果显著,固体中磷含量都低于0.24%;铁品位呈下降的趋势,但相对铁精矿都有一定程度的提高,而铁回收率也呈波动增加趋势,从最低的91.89%上升至95.50%。     

钛微合金化高强度耐候钢成分设计及熔炼

在普通耐候钢Q450NQR1成分的基础上,通过理论计算,设计出一种钛含量为0.04%～0.10%、屈服强度为520～750 MPa的高强度耐候钢。按照成分设计要求,采用高频真空感应炉在1 873 K条件下熔炼钢样,并对不同钛加入量的钢样进行成分和组织结构分析。结果表明,熔炼的钢样中氧含量为（17～26）×10-6,氮含量为（12～66）×10-6,钛含量为0.006 1%～0.059 0%;钢样组织主要由铁素体和珠光体构成,随着钢中钛含量的增加,晶粒明显细化,钢组织渐趋均匀。SEM分析表明,钢中长方体的TiN夹杂,是以球形的Al2O3、MgO和钛氧化物夹杂为核心生长的,必要时在微合金化处理之前将钢中的氧含量降低到一定程度。     

Application of Al-free deoxidizer in rail steel manufacture

Because there are a lot of influences of alumina inclusions on the performance of rail steel, it is reasonable to adopt the deoxidizatinn method with Al-free deoxidizer. According to the characteristics of Al-free deoxidization process, the control of alu-minum content, the denxidization with ladle furnace(LF) slag, the deoxidization process under vacuum by carbon, and the inclusions modification technology by calcium treatment were studied. All of them were applied to practical production. The results indicate that the adoption of Al-free deoxidization process leads to the total oxygen content in the steel below 20 ppm, which meets the re-quirement of clean rail steel.     

Al 脱氧弹簧钢钙处理过程中铝酸钙硫化物析出热力学分析

通过钢液与夹杂物间的热力学平衡计算,对Al脱氧弹簧钢钙处理过程中铝酸钙硫化物的析出行为进行热力学分析,探讨[Al]、[Ca]、[S]浓度和钢液温度对Al2O3夹杂物变性行为的影响。结果表明,1600℃钢液温度下,w[Al]＝0．03％时,Al2O3生成为低熔点12CaO ·7Al2O3时的 w[Ca]＞0．0034％,其值随钢液温度降低而减小,随铝含量增大而增大。CaS析出时的临界钙含量随钢液温度降低而显著减小,当w [S ]＜0．005％时,w[Ca]随w[S]变化而显著变化。要使钢中夹杂物控制在低熔点12CaO ·7Al2O3区域,需控制w [S]＜0．0037％,该值随钢液温度的降低或铝含量的增大而减小。     

CaO基熔剂对钢液二次精炼脱磷速度的研究

利用CaO-Fe2O3-CaF2系熔剂，对磷质量分数≤0.0050%的钢液进行二次精炼脱磷处理，测定熔剂中添加BaO，Al2O3时对钢液脱磷速度的影响关系，实验得到CaO基熔剂对钢液二次精炼处理时的脱磷反应速度常数k值以及磷在熔渣中传质系数D(p)/δ值，结果表明，添加剂BaO具有增大脱磷反应速度的作用，而Al2O3对脱磷反应速度影响不大。     

稀土对4145H钻铤钢动态再结晶的影响

应用Geeble-1500D热模拟试验机分别对稀土含量为6×10-6和16×10-6的钻铤钢进行单道次压缩实验,测定其不同终轧温度下的真应力-真应变曲线,采用应变速率0.01 s-1,变形量60%,终轧温度为850,950,1050,1150℃,研究不同稀土含量,不同终轧温度对钻铤钢再结晶的影响。结果表明,稀土含量为16的钻铤钢能显著地抑制形变奥氏体的动态再结晶。     

CaO基熔剂对钢液二次精炼脱磷速度的研究

利用CaO-Fe2O3-CaF2系熔剂，对磷质量分数≤0．050％的钢液进行二次精炼脱磷处理，测定熔剂中添加BaO，A12O3时对钢液脱磷速度的影响关系。实验得到CaO基熔剂对钢液二次精炼处理时的脱磷反应速度常数k值以及磷在熔渣中传质系数D(p)／δ值。结果表明：添加剂BaO具有增大脱磷反应速度的作用，而A12O3对脱磷反应速度影响不大。     

高锰钢还原脱磷的实验研究

本文针对当前工业生产中高锰钢的脱磷问题进行了实验研究。采用硅钙合金为脱磷剂进行还原脱磷。研究了硅钙粉的用量、CaF_2熔剂的加入量和温度等因素对脱磷率的影响。实验结果表明:可将钢液中磷含量迅速降低,脱磷率达到45％左右。     

Strengthening mechanism of steels treated by barium-bearing alloys

The deoxidation,desuifurization,dephosphorization,microstructure,and mechanical properties of steels treated by bar- ium-bearing alloys were investigated in laboratory and by industrial tests.The results show that barium takes part in the deoxidation reaction at the beginning of the experiments,generating oxide and sulfide compound inclusions,which easily float up from the mol- ten steel,leading to the rapid reduction of total oxygen content to a very low level.The desulfurization and dephosphorization capa- bilities of calcium-bearing alloys increase with the addition of barium.The results of OM and SEM observations and mechanical property tests show that the structure of the steel treated by barium-bearing alloys is refined remarkably,the lamellar thickness of pearlitic structure decreases,and the pearlitic morphology shows clustering distribution.Less barium exists in steel substrate and the enrichment of barium-bearing precipitated phase mostly occurs in grain boundary and phase boundary,which can prevent the move- ment of grain boundary and dislocation during the heat treatment and the deformation processes.Therefore,the strength and tough- ness of barium-treated steels are improved by the effect of grain-boundary strengthening and nail-prick dislocation.     

高炉锰铁脱硅脱磷的实验研究

通过对高炉锰铁预脱硅试验，研究了ＢａＯ渣系和ＣａＯ渣系的脱硅能力以及添加Ｆｅ＿２Ｏ＿３、ＭｎＯ＿２等对渣系脱硅的影响。在对锰铁氧化脱磷试验中，研究了初始硅含量、ＢａＣＯ＿３熔剂用量以及配入Ｆｅ＿２Ｏ＿３对脱磷的影响。结果表明高炉锰铁经一次预脱硅处理，使硅降至０．２３％以下便可进行氧化脱磷处理。     

Removal of phosphorus from iron ores by chemical leaching

1 INTRODUCTION With the rise of the price of iron ores in the global market, the iron and steel companies in China have to increase the proportion of domestic iron ores in iron-making production. However, iron ores produced in China commonly contain many impurities, such as phosphorus, sulphur, silica, etc[1]. Phosphorus is one of the main harmful elements to ferrous metallurgy, and it will affect the quality of iron and steel products[2]. At present, China has explored some large mines,…     

以亚硝酸盐为电子受体的反硝化除磷系统的启动及除磷效果

目的实现以亚硝酸盐为电子受体的反硝化除磷系统的启动,并对系统的除磷效果进行考察．方法采用分阶段培养驯化的方式进行启动,第一个阶段通过厌氧／好氧交替运行富集聚磷菌,剩下的两个阶段通过先投加NO3^-N,再由电子受体NO3^-N过渡到NO2^-N的方式对以NO2^-N为电子受体的反硝化聚磷菌（DPAO）进行筛选．结果经过131d的运行,成功地实现了系统的启动,且稳定后的系统具有良好的反硝化除磷能力,出水P（PO4^3-）仅为0．86mg／L,磷的去除率达到了89％左右．结论最终启动完成之后,以NO2^-N为电子受体．从各阶段磷的去除率可以看出,不同电子受体作用下除磷率有所不同,除磷效果由高到低依次为O2〉NO3^--N〉NO2^-N．     

Mathematical model of deoxidization with post stirring in a combined blowing converter

Dissolved oxygen in the steel at the terminal of the converter smelting process is the main cause for the formation of oxide inclusions, and the high terminal oxygen content worsens the steel cleanness. However, post stirring in a combined blowing converter can promote the carbon-oxygen reaction in the liquid steel and reduce the dissolved oxygen content at the terminal of the converter smelting process. Thus, the mathematical model of deoxidization in the post stirring process was obtained, and the rationa...     

钢包耐火材料对钢中氧含量及钢水温降的影响

利用氧势指数分析了钢包耐火材料组成、配比以及加热温度对耐火材料分解和向钢中传氧的影响,并利用热传导理论计算了钢包包衬耐火材料的绝热性能对钢水温降的影响.结果表明：随着耐火材料材质由碱性向中性和酸性的顺序变化及温度的升高,耐火材料的氧势指数增大,由耐火材料向钢中的传氧能力增加;通过使用绝热性能良好的耐火材料,可以显著降低钢水热损失,减少钢水温降.