Formation and Modification of MgO·Al2O3-Based Inclusions in Alloy Steels

The current study performed thermadynamic calculation, laboratory experiments, and industrial trials for the formation and modification of MgO-Al₂O₃ spinel inclusions in alloy steels. The stability Mg-Al-O diagram was obtained using the thermodymanic study. The resulting MgO-Al₂O₃-CaO inclusions from MgO-Al₂O₃ spinel inclusions after the calcium treatment were spherical, and?>?5???m MgO-Al₂O₃-CaO inclusions have a two-layer structure: an outside CaO-Al₂O₃ layer and a MgO-Al₂O₃ core. The modification of?>?5???m MgO·Al₂O₃ spinel inclusions by calcium treatment includes two steps: (1) reducing MgO in the inclusion into the dissolved magnesium by the dissolved calcium in the steel and (2) generating a liquid xCaO·yAl₂O₃ layer at the outside of the spinel inclusion. For <2???m MgO·Al₂O₃ spinel inclusions, they can possibly be modified into a xCaO·yAl₂O₃ inclusion by reducing all MgO component in the spinel inclusions with the added calcium.     

Formation Mechanism of Al2O3-Containing Inclusions in Al-Deoxidized Spring Steel

Metallurgical and Materials Transactions B - The source, characteristics, and mechanism of Al2O3-containing inclusions in Al-deoxidized spring steel were investigated using electron-probe X-ray...     

Influence of Prior Austenite Deformation and Non-Metallic Inclusions on Ferrite Formation in Low-Carbon Steels

Effects of prior austenite deformation and non-metallic inclusions on the ferrite nucleation and grain refinement of two kinds of low-carbon steels have been studied. The ferrite nucleation on MnS and V(C,N) is observed. The combination of thermomechanical processes with adequate amounts of non-metallic inclusions formed in low-carbon steels could effectively refine the grain size and the microstructure. Ferrite nucleated on the single MnS or V(CN) inclusions and complex MnS+V(C,N) inclusion. The proper addition of elements S and V could effectively promote the formation of ferrite and further refinement of ferrite grains.     

无取向电工钢中酸溶铝含量对夹杂物的影响

 为提高无取向电工钢成品性能及优化生产,采用SEM-EDS等分析方法分别对比分析了无取向电工钢生产时,不同酸溶铝含量的生产工艺对钢中夹杂物的影响。研究表明,当钢中酸溶铝含量w(Als)为0.2%～0.4%时,精炼过程所生成的夹杂物为高熔点的Al2O3和球状的MgO-Al2O3类夹杂物;当钢中w(Als)小于0.005%时,精炼过程所生成的夹杂物主要为塑性硅铝锰酸盐类夹杂;各工位夹杂物平均数量呈递减的趋势,且w(Als)为02%～0.4%的高碱度渣系控制生成的夹杂物总量低于后者。     

CSP生产无取向电工钢的组织和性能

 研究了采用CSP流程生产的无取向电工钢的金相组织、第二相粒子分布、磁性能。结果表明,采用CSP流程生产的无取向电工钢热轧板成品均为均匀粗大的等轴晶;热轧板中第二相粒子平均尺寸在150 nm左右,且随(Si+Al)含量的增加,第二相粒子的类型发生明显的变化;CSP流程生产的无取向电工钢磁性能得到明显的提高。     

Numerical Simulation of Fractal Agglomerating-Growth of Al2O3 Inclusions in Tundish

Based on the Al₂O₃ inclusion analysis of low-carbon aluminum killed steel in tundish of a domestic steel company and fractal theory analysis, a mathematical model of fractal agglomerating-growth of Al₂O₃ inclusions in tundish was established. The results indicated that: large swirl flows exist in both sides of inlet, space between weir and dam, and large zone above outlet, in which monomer and agglomerated inclusion particles accumulate easily; the agglomerated inclusions with hydrodynamic diameter of 6 — 9.8 μm were quickly generated less than 16 s, but those inclusions with hydrodynamic diameter more than 11 μm were difficult to form; the number density of agglomerated inclusion rapidly increased first, then slowly reduced, so the form and quantity distribution of agglomerated inclusions can be controlled by controlling the residence time of inclusion particles in tundish.     

Effects of Sn Addition on Core Loss and Texture of Non-Oriented Electrical Steels

The effects of Sn addition on core loss and texture of non-oriented electrical steels were investigated. Ex-periments revealed that the core loss of non-oriented electrical steels could be obviously decreased and the intensity of {111} texture and {112} texture of final annealed specimens could be markedly reduced by Sn addition. The reasons for reducing core loss and the intensity of unfavorable texture were analyzed.     

V2O3、Al2O3添加剂对碳化铁生成的影响

在1 023 K用热重法结合XRD分析,研究了V2O3、Al2O3添加剂对混合气体(H2 CHI)还原铁矿石制备碳化铁的影响.研究表明:V2O3对还原反应和碳化反应均有明显的促进作用,有利于提高碳化铁的生成率和稳定性.当V2O3含量在1%以内时,随着V2O3的增加,铁矿石还原速率逐渐加快,碳化速率也提高,促进效果明显;当V2O3含量高于1%,试样还原速率和碳化速率均比1%时略小.Al2O3对还原和碳化有一定的促进作用,但对碳化铁的稳定性有不利的影响.     

MgO基和Al2O3基耐火材料对钢中夹杂物的影响

利用大样电解、图像分析、扫描电镜和能谱分析等检测手段研究了82B钢种选用Al2O3-MgO、MgO-Al2O3和MgO-CaO炉衬在1450 ℃保持80 min后生成的夹杂物种类和变化.结果表明,采用Al2O3-MgO作内衬时冶炼后钢中夹杂物的数量增加了近50%,夹杂物的尺寸大(100～900 μm)且硬度很高,夹杂物的主要成分为SiO2和Al2O3;以MgO-Al2O3作内衬时夹杂物数量略有降低(30%),尺寸(80～450 μm)和硬度相对较小,其主要成分为SiO2、MnO、CaO和MgO;而MgO-CaO材料对去除钢中夹杂物(降低70%)和降低其尺寸(30～350 μm)有明显效果,且夹杂物的硬度很小,其主要成分为CaO、Al2O3、SiO2和FeO.采用MgO-CaO材料时夹杂物的尺寸最小、数量最少,对钢水洁净度的贡献最大.     

双辊薄带连铸对无取向电工钢组织和性能的影响

实验室20kg感应炉冶炼的成分(％)为：0．001～0．004C，0．17～3．00Si无取向电工钢水注入SLB-1双辊薄带连铸机的水冷结晶辊和侧封板形成的熔池中，铸成2．0～3．0mm铸带，再经表面研磨和冷轧成0．5mm的带钢。试验结果表明，铸带组织为经过再结晶的粗大等轴晶结构，由连铸薄带轧成的冷轧带成品的铁损与常规产品相当，磁感较常规产品高0．04～0．06T，因为双辊连铸薄带成品有利面织构比率高于常规产品。     

CaF_2-MgF_2对钢中Al_2O_3夹杂物去除作用的研究

采用不同量的CaF_2、MgF_2、Na_3AlF6以及CaF_2与MgF_2的混合物对钢液中Al_2O_3夹杂物进行改性处理。结果表明:经过改性处理后的钢中全氧含量都有明显的降低,但其添加量需要在一个合适的范围,其中添加1.0%的CaF_2与MgF_2的混合改性剂的效果最好。另外经过改性剂处理后的钢中夹杂物呈现出MnS包裹Al_2O_3的复合分层形态,更加有利于夹杂物的上浮去除,而且MnS为塑性夹杂物,可降低残留在钢中Al_2O_3夹杂物对钢的危害。     

Transient Behavior and Thermodynamics of Inclusions in Al-Ti-Deoxidized and Ca-Treated Steel

Metallurgical and Materials Transactions B - Ti-alloyed steels have severe nozzle clogging problems, which are detrimental to the steel production process. However, little research on the...     

控制高铝钢45CrAlMo中Al2O3夹杂的工艺实践

45CrAlMo钢（/%:0.40～0.50C,≤0.60Mn,0.15～0.45Si,1.30～1.70Cr,0.15～0.30Mo,0.85～1.20Al）的生产工艺流程为60 t EAF-LF-VD-氩气保护浇铸2.1 t锭-锻成120 mm×120 mm材。分析了电弧炉冶炼和LF精炼过程脱氧,VD脱气、浇铸过程的工艺参数对钢中氧含量和Al₂O₃夹杂的影响。通过将LF终点S含量从≤0.015%降至0.008%,喂铝线改成加铝锭、VD真空度从100 Pa降至67 Pa,加CaSi改成不进行Ca处理,浇铸温度从1 585～1 595℃降至1 570～1 580℃等工艺措施,消除了低倍点状夹杂,B类和D类夹杂分别从1.5级降至0.5级,探伤合格率从67%提高到98%,成材率由55%提高到68%。     

铬酸镧/氧化铝复合材料的烧结机制与性能

将掺Ca铬酸镧与Al2O3混合,在1650℃烧结得到氧化铝量从0~100%(摩尔分数)的系列Al2O3/La0.9Ca0.1CrO3复合材料烧结体。研究得出Al2O3/La0.9Ca0.1CrO3系统是热力学不稳定的,高温烧结时存在离子扩散,烧结体的最终相组成与Al2O3量有关。复合材料中氧化铝含量较低时(≤20%,摩尔分数)可以提高铬酸镧粉体的烧结性能;当氧化铝含量在30%~70%(摩尔分数)之间时,生成的层片状六铝酸镧使烧结致密度降低,并在氧化铝含量为70%(摩尔分数)时达到最低值,随后试样的相对密度又逐渐增大。     

Behavior of MgO·Al_2O_3 Based Inclusions in Alloy Steel During Refining Process

The transformation of MgO·Al2O3 based inclusions in alloy steel during refining has been studied by industrial trials.Besides Factsage software is used to study the formation and modification of spinel inclusions in alloy steel using calcium treatment during refining process.The results show that the transformation sequence of inclusions is:MgO·Al2O3→CaO-Al2O3-MgO complex inclusions→MgO·Al2O3,and under present experimental condition,in order to avoid forming MgO·Al2O3 inclusions the content of dissolved Ca in the molten steel has to reach 1×10-6.Also the results show that when more calcium was added to molten steel,the content of Al2O3 and MgO will be lower.Besides,increasing the content of CaO in the inclusions will increase even if the content of SiO2 changes little.     

稀土铈对2.9%Si无取向硅钢磁性能的影响

 摘 要： 为了获得磁性能优良的高牌号无取向硅钢,系统地研究了稀土铈对2.9%Si无取向硅钢中夹杂物的变质及粗化,退火板的组织、织构及磁性能的影响规律。结果表明：钢中添加适量（质量分数0.005 5%）的铈能使夹杂物聚集粗化,最终使成品再结晶晶粒尺寸增大,有利织构组分{100}和{110}面织构增多,不利织构组分{111}面织构减少,磁性能达到最佳。但是当铈添加过量（质量分数0.019%）时,其作用反而相反。     

IF钢中Al_2O_3-TiN复合夹杂生成机理研究

通过形核理论解释了IF钢中Al2O3-Ti N的形成机理。RH中加TiFe合金化后由于局部wTi.wN浓度积有很大的过饱和度,满足异质形核条件,Ti N会以钢液中Al2O3为核心生成Al2O3-Ti N复合夹杂,但此时的Ti N并不稳定会随着钢液中wTi浓度的均匀而发生分解,在凝固过程中由于温度的降低和wTi的偏析会在凝固前沿Ti N再次析出。