Effects of calcium treatment on non-metallic inclusions and magnetic properties of non-oriented silicon steel sheets

Based on the industrial production of non-oriented silicon steel,calcium treatment by CaSi wire feeding during the RH refining process was studied. The thermodynamics of CaS inclusion formation was analyzed, and the morphology and the size distribution were observed. Furthermore, the change in inclusion characteristics after calcium treatment and the effect of calcium treatment on magnetic properties were discussed. The results show that the formation of MnS and A1N inclusions were restrained, and the aggregating, floating and removing of microinclusions after calcium treatment were effectively promoted. The cleanliness of liquid steel was obviously increased. The main type of inclusions was single phase of CaO, with some complex inclusions composed of CaO, SiO2 and MgO. No CaS inclusion was observed after an appropriate calcium treatment. The size of all inclusions was distributed in the range of 2 - 20 μm, and the number was about 1.8 × 10^5/mm3. In addition, as an increasing amount of calcium was added,the core loss gradually decreased to a stable level, and the magnetic induction decreased quickly after a slow increase. The optimal calcium treatment mode depends on the chemical composition of steel.

Effect of Calcium Treatment During Production on Quality of Stored Huangguan Pear Fruit

The effect of calcium treatment during production on the quality(soluble solids, fruit firmness, soluble sugar content, titratable acid content, etc.) of Huangguan pear was studied. The results showed that the calcium treatment during production improved the comprehensive quality of Huangguan pear fruit, delayed and reduced the occurrence of browning of fruit core, and enhanced its storage effect in the cold storage. Therefore, the calcium treatment improved the quality of stored pear fruit.

Denaturation behavior of inclusions in industrial pure iron by calcium treatment

Only a few Chinese enterprises can produce high-quality industrial pure iron,and studies on the smelting process of industrial pure iron were limited.The inclusions in a melting process were characterized by means of electron microscopy and an automatic inclusion analysis system,and the evolution mechanism of inclusion was studied using thermodynamic calculation to optimize the calcium alloy addition in liquid window.The results show that during the smelting process,inclusions mainly composed of Al_(2)O_(3)and spinel are formed before calcium treatment.After calcium treatment,they continuously react with[Ca],[S]and[Ti],grow up,and are removed during refining and tundish pouring.In the end,there are more small-sized inclusions containing CaS,and the contents of Al_(2)O_(3)and spinel are less.According to thermodynamic calculations,the appropriate calcium treatment liquid window for the molten steel composition is(10-38)×10^(-6).Calcium treatment has changed the main types of inclusions in industrial pure iron from Al_(2)O_(3)to small-sized inclusions containing CaS and effectively reduces the influence of Al_(2)O_(3)inclusions on the quality of industrial pure iron.

Effect of Calcium Treatment on Non-Metallic Inclusions in Ultra-Low Oxygen Steel Refined by High Basicity High Al_2O_3 Slag

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 nonmetallic 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. Further- more, 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.

Inclusion engineering and metallurgy of calcium treatment

Although a great deal of research has been done in the area of inclusion control during steelmaking, a complete description of the process of inclusion modification and shape control cannot be found in literatures. As a result, the terms ＂inclusion modification＂ and ＂shape control＂ are often used loosely in the technical community. To utilize the full potential offered by a calcium treatment, it is important to understand why an inclusion whose composition has been modified may not necessarily have its shape modified. With the purpose of decoupling the process of inclusion phase change from inclusion shape control, and to provide a complete description of the metallurgy of calcium treatment, a detailed literature survey has been performed on the subject. By coupling the survey with a new concept developed to tailor the cleanliness of steels to the intended applications, the hope is to provide the reader with valuable information on calcium treatment for inclusion modification and shape control.

Vitamin D and calcium are required at the time of denosumab administration during osteoporosis treatment

To evaluate the differences in outcomes of treatment with denosumab alone or denosumab combined with vitamin D and calcium supplementation in patients with primary osteoporosis. Patients were split into a denosumab monotherapy group （18 cases） or a denosumab plus vitamin D supplementation group （combination group; 23 cases）. We measured serum bone alkaline phosphatase （BAP）, tartrate-resistant acid phosphatase （TRACP）-5b and urinary N-terminal telopeptide of type-I collagen （NTX） at baseline, 1 week, as well as at I month and 2, 4, 8 and 12 months. We also measured bone mineral density （BMD） of L1-4 lumbar vertebrae （L）-BMD and bilateral hips （H）-BMD at baseline and at 4, 8 and 12 months. There was no significant difference in patient background. TRACP-5b and urinary NTX were significantly suppressed in both groups from I week to 12 months （except at 12 months for NTX）. In the combination group, TRACP-5b was significantly decreased compared with the denosumab monotherapy group at 2 and 4 months （P 〈 0.05）. BAP was significantly suppressed in both groups at 2-12 months. L-BMD significantly increased at 8 and 12 months （8.9%） in the combination group and at 4, 8 and 12 months （6.0%） in the denosumab monotherapy group, compared with those before treatment. H-BMD was significantly increased in the combination group （3.6%） compared with the denosumab group （1.2%） at 12 months （P 〈 0.05）. Compared with denosumab monotherapy, combination therapy of denosumab with vitamin D and calcium stopped the decrease in calcium caused by denosumab, inhibited bone metabolism to a greater extent, and increased BMD （especially at the hips）.

Alkaline treatment kinetics of calcium phosphate by piezoelectric quartz crystal impedance

Calcium phosphate film was prepared by electrochemical deposition technology. Subsequently, the alkaline treatment process of calcium phosphate film in 0.1 mol/L NaOH solution was monitored on real time by the piezoelectric quartz crystal impedance (PQCI) technique. The variations of morphology and composition for the alkaline treatment products were characterized by scanning electron microscopy (SEM), Fourier transform infrared (FT-IR) and X-ray diffraction (XRD), respectively. The dynamic variations of calcium phosphate can be characterized by the change of equivalent circuit parameters. The results show that the forming process of hydroxyapatite (HA) is composed of three stages: (1) acidic calcium phosphate dissolution; (2) phase transformation; and (3) HA formation. Furthermore, the correlative kinetic equations and parameters are obtained by fitting the static capacitance (Cs)—time curves.

管线钢X65连铸过程絮流原因分析

通过对低碳低硫低氧铝镇静钢X65连铸过程絮流原因的分析,得出引起塞棒絮流的原因是高Ca的钙铝酸盐粘附在塞棒头部。浇注初期,塞棒头部吸热使周围钢液温度急剧下降,析出高熔点钙铝酸盐被粘附在塞棒头部,引起塞棒曲线上行。另外,通过热力学计算,在低碳低硫低氧铝镇静钢X65中,1 540℃时,形成12CaO·7Al_(2)O_(3)需要的w[Ca]为16×10^(-6),过量的Ca进一步反应形成高熔点钙铝酸盐。在中间包工作层、塞棒、水口、碗口等与钢水接触部位全部使用镁质耐材的条件下,在低碳低硫低氧的铝镇静钢生产时,向钢液中喂入的Ca含量越多,塞棒上行程度越严重。采用高碱度渣系和Al降低钢中的O和S,将Ca喂入量控制在0.065 0~0.071 5 kg/t,中间包w[Ca]控制在(10~15)×10^(-6),可以有效控制塞棒絮流。

阿托伐他汀钙联合苯磺酸氨氯地平治疗动脉粥样硬化的临床研究

目的探讨阿托伐他汀钙联合苯磺酸氨氯地平治疗动脉粥样硬化的临床效果。方法选取2020年2月至2023年2月我院收治的74例动脉粥样硬化患者,随机分为对照组(37例,苯磺酸氨氯地平)和观察组(37例,阿托伐他汀钙联合苯磺酸氨氯地平)。比较两组的治疗效果、血脂水平及脂蛋白相关磷脂酶A2(LP-PLA2)水平。结果观察组治疗总有效率、HDL-C水平明显高于对照组,TC、TG、LDL-C及LP-PLA2水平明显低于对照组(P<0.05)。结论阿托伐他汀钙联合苯磺酸氨氯地平治疗动脉粥样硬化的效果显著,对调节患者血脂代谢、改善血管炎性状态具有积极作用。

不同碱度渣对42CrMoS4钢中硫化物的影响

为研究不同精炼工艺对齿圈钢42CrMoS4钢中硫化物的影响,从钢中硫化物的形态与分布着手,在精炼工序设计两种不同的碱度渣和钙含量工艺,试验生产4炉。对比分析铸坯和轧材中不同双层结构复合硫化物特征与硫化物形成机理。结果表明,LF造高碱度渣(R=6.5~7.2)进RH后不进行钙处理,铸坯1/4厚度位置复合硫化物整体成块状形貌,核心内部氧化物同样也成规则的块状,轧材内部氧化物主要以CaO为主,外围硫化物主要是高CaS比例的(Ca,Mn)S,基本不变形,A类细系夹杂物级别为2.0~3.0级;在LF造弱碱度渣(R=3.6~4.2)进RH后进行二次钙处理,将w[Ca]由0.001 4%左右提升至0.002 5%~0.003 2%,铸坯1/4厚度位置复合硫化物整体成椭球状形貌,核心内部氧化物同样也成规则的球状,轧材内部氧化物为较低CaO比例的钙镁铝酸盐,外围硫化物主要是低CaS比例的(Ca,Mn)S,硫化物成纺锤状,具有很好的变形能力,A类细系夹杂物级别控制在2.0级以内。

Effect of calcium content on inclusions during the ladle furnace refining process of AISI 321 stainless steel

The effect of three heat processes with different calcium contents on the evolution of inclusions during the ladle furnace refining process of AISI 321 stainless steel was investigated.The size,morphology,and composition of the inclusions were analyzed by scanning electron microscopy and energy-dispersive X-ray spectroscopy.After the addition of aluminum and titanium,the primary oxide in the AISI 321 stainless steel was an AbOs—MgO—TiOx complex oxide,in which the mass ratio of AbOs/MgO was highly consistent with spinel(MgO・AbO3).After calcium treatment,the calcium content in the oxide increased significantly.Thermodynamic calculations show that when the Ti content was 0.2wt%,the Al and Ca contents were less than 0.10wt%and 0.0005wt%,respectively,which was beneficial for the formation of liquid inclusions in molten steel.Moreover,the modification mechanism of calcium on TiN-wrapped oxides in combination with temperature changes was discussed.

钢液钙处理过程有效钙硫比对303 t超大钢锭中硫化物形貌的影响

通过工业实验研究了钙处理对303 t的16Mn重型管板铸锭中硫化物形貌的控制.未钙处理的锻件缺陷主要分布在轴向上靠近顶部、径向上在距中心1/2以内位置,缺陷主要为大尺寸Ⅱ类MnS夹杂物.采用Micro-CT检测了铸锭顶部中心位置MnS夹杂物三维分布,夹杂物为长条状和片状,数密度为0.77 mm^(-3),最大直径为1370μm.在真空脱气后对钢液进行钙处理,钙处理不仅将钢液中原生Al_(2)O_(3)夹杂物改性为液态钙铝酸盐,并且钙会在钢液凝固和冷却过程中优于锰先与硫结合生成CaS.通过FactSage热力学计算得到,钙处理将MnS夹杂物的析出温度由1244.7℃降低至1227.9℃,同时减少了MnS夹杂物析出量.钙在改性硫化物之前先改性了钢中氧化物,因此提出了有效钙硫比Ca/Seff.用来表征钙处理对硫化物形貌的影响,Ca/Seff.的含义为改性硫化物的有效钙和钢中硫的原子浓度比,可以直接根据钢液的总氧T.O含量、总硫T.S含量和总钙T.Ca含量计算得到,此公式适用于硫质量分数小于30×10^(-6)的低硫钢.随着钢中Ca/Seff.增加,铸锭顶部硫化物长宽比逐渐减小.钙处理后钢中有效钙硫比Ca/Seff.应大于0.8,铸锭顶部硫化物平均长宽比小于1.2,CaS和MnS复合硫化物以钙铝酸盐夹杂物为核心析出,硫化物为球形且尺寸显著减小,此时钙处理改性铸锭中硫化物效果较好.

基于蒸制处理的黄精麻味物质研究

目的:探索黄精产生麻味特征的物质基础。方法:采用“九蒸九制”的方法对8个产地的黄精进行炮制,并分析不同蒸制次数下黄精中皂苷、多酚、草酸钙针晶含量的变化;采用细胞溶血率试验以及感官评价方法评价黄精麻味程度的变化,并进行麻味相关性分析。结果:随着蒸制次数的增加,不同产地的黄精中多酚和皂苷含量均呈先升后降的趋势,而草酸钙针晶含量、细胞溶血率以及麻味评分均逐渐下降;相关性分析表明,草酸钙针晶含量与黄精麻感程度之间呈显著正相关(P<0.05)或者极显著正相关(P<0.01);扫描电镜结果显示,蒸制处理后草酸钙针晶结构逐步遭到破坏,与黄精麻味的变化规律相吻合。结论:草酸钙针晶是黄精具有麻味特征的关键物质。

腺泡细胞钙离子超载与急性胰腺炎关系的研究进展

急性胰腺炎(AP)是消化科的常见的疾病类型之一,大多数患者病情轻微,但约25%的患者会发展为重症胰腺炎,其中重症胰腺炎的致死率则高达30%~50%。国内诸多对AP病因病机的基础研究显示,使用雨蛙素法、无胆盐乙硫氨酸食物诱导法、胆胰管逆行牛黄胆酸钠注射法诱导的AP动物模型中腺泡细胞内钙离子浓度均持续增高,进而引起胞内钙离子依赖性的酶原颗粒提前活化、空泡形成最终导致细胞凋亡,以上结论均提示腺泡细胞钙离子超载在AP的发生发展中起到至关重要的作用,而针对AP的治疗目前临床上缺乏高效且具有针对性的靶向药物,故探索维持细胞内钙稳态的机制及腺泡细胞钙超载所引起的病理过程,可为研究AP的直接靶向治疗药物提供新思路。该文就细胞内钙稳态与调控、腺泡细胞钙超载的发生、Ca2+超载在AP发病机制中的作用、腺泡细胞Ca2+超载的临床诊治方法的研究进展作一综述。

低硫非调质钢水口结瘤机理解析

非调质钢含有较高的铝,经钙处理工艺后,易导致水口结瘤。采用X射线衍射仪、扫描电子显微镜分析了某厂低硫非调质钢连铸水口结瘤物试样,结合热力学计算分析,揭示水口结瘤的原因。研究表明:水口结瘤物主要为CaS,其在钢液凝固过程中从钢液中以直接、间接两种方式析出,钙添加过量是导致水口结瘤的主要原因,后续可通过优化钢液的钙铝比来保证连铸的顺行,消除结瘤现象。

还原型谷胱甘肽联合急诊常规治疗对急性有机磷中毒患者的疗效分析

目的分析还原型谷胱甘肽联合急诊常规治疗对急性有机磷中毒患者的疗效。方法回顾性分析2018年1月—2023年1月于本院就诊的急性有机磷中毒患者共计50例,依照治疗方式分为参比组和分析组。参比组(n=25,常规急诊治疗),分析组(n=25,常规急诊治疗+还原型谷胱甘肽治疗)。比较两组治疗效果。结果分析组治疗后临床症状转归指标(M样症状消失时间、肌酸激酶恢复时间、心肌钙蛋白恢复时间、CHE活力恢复时间)均显著短于参比组(P<0.05);分析组治疗后肝功能指标(ALT、AST、ALB)改善情况均显著优于参比组(P<0.05)。分析组治疗1d、7d后CHE活性均显著高于参比组(P<0.05)。分析组临床疗效高于参比组(P<0.05)。结论针对急性有机磷中毒患者,在常规急诊治疗基础上,联合应用还原型谷胱甘肽,有利于肝功能及CHE活性转归,可缩短临床症状转归时间,于临床疗效提升有显著增益。

浸渗处理及真空度对喷射粘结成形氧化钙基陶瓷型芯性能影响

采用喷射粘结成形技术,以重质碳酸钙作为原料,浸渗纳米ZrO2分散液后烧结得到了氧化钙基陶瓷型芯,研究了浸渗处理以及浸渗真空度对陶瓷型芯性能的影响。研究发现,浸渗处理后的陶瓷型芯内部生成了大量CaZrO3,使内部孔隙减少,微观组织更加致密,弯曲强度最大增加幅度为277.87%。浸渗处理时增大真空度可以进一步改善陶瓷型芯的性能,当真空度从0增加至0.05 MPa时,弯曲强度由7.15 MPa提升到8.88 MPa,但当真空度进一步增加至0.08 MPa时,弯曲强度却降至6.85 MPa,陶瓷型芯性能降低。不同处理工艺烧结后得到的陶瓷型芯浸泡在热水中5 min后即开始溃散,表现出良好的可溶性。

钙处理工艺对钢中夹杂物的影响分析及应用

针对钙处理工艺对钢水洁净度影响的问题,使用平衡相图进行不同钙含量下生成的夹杂物类型、含量对比分析,结果表明:随着钢中钙含量升高,钢中氧化物夹杂数密度从钙含量1×10^(-6)时的0.52个/mm^(2)降至0.4个/mm^(2);钢中大尺寸夹杂数密度先上升后下降,从钙含量1×10^(-6)时的0.005个/mm降至0.004个/mm^(2);同时随着钢中氧含量的增加,钢中溶解钙含量在3~4×10^(-6),变化不大,钙的活度明显受到抑制。