高压气瓶钢34Mn2V 200 mm×200 mm轧坯角部拉裂缺陷的控制工艺

通过工艺对比分析了34Mn2V高压气瓶用钢中间包浇铸温度、结晶器液面波动、[Als]、中问包炉次和280 mm×380 mm连铸坯拉速波动对轧坯角部拉裂的影响。提出减小RH加Al量,按[Als]0.01%控制;RH后喂Ca-Si线;适当提高连铸钢液温度,控制中间包钢水温度1 520～1 530℃;控制浇铸过程塞棒吹氩量≤10 L/min;结晶器液位波动±3 mm等工艺措施。应用结果表明,轧坯角部拉裂缺陷率由原来的23.57%降至1.21%。     

钢包长水口吹氩自动控制系统研究与应用

摘要：钢包长水口吹氩采用最佳的流量控制策略，能有效避免中间包浇注过程中出现钢液二次氧化、卷渣和热量损失等负面影响，同时，能充分发挥气泡去除夹杂物的作用。为此，提出钢包长水口吹氩自动控制系统，通过S7-300PLC采集数据及软件编程，根据开浇、连浇等因素在线调节吹氩流量，在此基础上运用PID控制算法和闭环控制机制实时调整流量控制阀，保证流量实际值与设定值偏差最小。此系统在某特钢厂2021年第1季度生产数据表明，各钢种连铸坯酸溶铝（Als）损失百分比小于10%的炉数比例上升了5.52%，Als损失百分比大于60%的炉数比例由1%下降为0。实际应用结果表明，该系统提高了连铸坯表面质量及最终成品性能。     

IF钢氮含量控制技术研究

介绍了鞍钢第二炼钢厂几年来在生产IF钢过程中对于氮成分控制方面所做的探索和研究,总结出低氮钢的生产技术和防止增氮技术。低氮钢的生产工艺包括转炉冶炼工序提高铁水比、冶炼过程控制返干、冶炼终点减少补吹次数和时间,采用铁矿石造渣,可以显著地降低转炉冶炼终点的氮含量;RH-TB精炼工序处理前期提高脱碳速度,处理中期快速提高真空度、提高提升氩气流量和钢水循环量,处理后期控制钢水中的氧含量,同时必须保证钢水极低的硫含量。防止增氮技术包括转炉冶炼工序出钢采用两步脱氧法、加强出钢口的维护、控制好大包顶渣、加强氩站吹氩操作;RH-TB精炼工序加强真空室的密封、控制合金增氮量以及大包顶渣的二次改质;板坯连铸工序控制长水口吹氩量、在长水口和大包下水口间增加新型密封垫、加强中间包密封、加强开浇操作控制、中间包大渣量操作、大包连浇操作优化、加强中间包滑板密封、开发专用保护渣等。实践表明,通过这两项技术的开发和应用,IF钢成品氮成分控制水平显著提高并趋于稳定。     

超低碳IF钢头坯洁净度的研究

对比分析超低碳IF钢浇次头坯、过渡坯和尾坯的洁净度发现,非稳态头坯洁净度远差于其它铸坯,换钢包交接坯和尾坯洁净度满足质量要求。提出了改善头坯洁净度的措施,即浇铸前中间包吹氩以减少浇铸初期钢水的二次氧化、优化中间包堰坝结构以增加中间包堰坝吸附夹杂物的能力。采取措施后,浇次头坯洁净度得到了提高,钢种夹杂废品率降低。     

中间包吹氩去除钢水夹杂物

通过现场实验,研究了中间包吹氩位置和氩气流量对钢水洁净度的影响,重点探讨了在注流区吹氩对钢水洁净度的影响.结果表明:在T型中间包注流区内进行合适流量吹氩可提高钢水洁净度,在浇铸区拐角处和塞棒附近吹氩对钢水洁净度没有明显的影响;在注流区内吹氩,合适的氩气流量为6L·min-1,与不吹氩相比,钢中总氧降低率和夹杂物的去除率均可提高10%左右,但15L·min-1的大流量吹氩将会显著增加钢中总氧和大型夹杂物数量.分析认为:注流区内大的湍流强度可将氩气泡击碎成弥散小气泡,大量小气泡在钢液中上浮,不但提高了气泡捕捉夹杂物的概率,而且增加了夹杂物之间的碰撞机会,其结果是增大了夹杂物的粒径,促进了夹杂物的上浮去除;同时,注流区离水口距离最远,在注流区吹氩,碰撞长大的夹杂物有更长的时间上浮排出.以上两个因素的共同作用,使得在注流区吹氩对去除钢水夹杂物有显著效果.     

方坯中间包包盖吹氩数值计算研究与应用

连铸过程中，通过包盖向中间包内吹入氩气可降低中间包内氧气质量分数，增强中间包保护浇注效果，减少钢水二次氧化。以6流方坯中间包为对象，针对其空包阶段与稳浇阶段包盖吹氩过程建立数值计算模型。为验证模型准确性，采用手持烟气分析仪测定了不同吹氩流量和不同吹氩时刻中间包氧气含量，并与计算值进行了对比，发现两者相对误差小于7.5%。基于该模型计算分析了采用不同工艺方案(包括吹氩管布局、氩气流量、吹氩时间)进行包盖吹氩时中间包氧气含量变化规律，据此确定了合理的包盖吹氩工艺方案为，吹氩管布放于包盖孔两侧，烘烤孔密封、塞棒孔畅通，空包吹氩阶段氩气流量不小于120 m³/h,中间包稳浇阶段氩气流量不小于60 m³/h。采用该工艺方案开展了工业试验，中间包内的氧气质量分数可稳定维持在0.1%以下，RH出站至中间包钢水增氮降低18.3%,由7.1×10^-6降低至5.8×10^-6,钢轨B、C类夹杂物评级得到改善。研究结果为设计中间包包盖吹氩工艺、增强中间包保护浇注效果提供了理论指导。     

关于中间包水口吹氩的水模拟试验

一、前言中间包水口吹氩,指的是在连铸浇钢时,在中间包水口处吹入氩气的一种工艺方法。关于中间包水口吹氩的试验研究,起初只是为了解决浇注铝镇静钢时的水口堵塞问     

高压气瓶钢34Mn2V 200mm×200mm轧坯角部拉裂缺陷的控制工艺

通过工艺对比分析了34Mn2V高压气瓶用钢中间包浇铸温度、结晶器液面波动、[Als]、中间包炉次和280mm×380mm连铸坯拉速波动对轧坯角部拉裂的影响。提出减小RH加Al量,按[Als]O．01％控制;RH后喂Ca—Si线;适当提高连铸钢液温度,控制中间包钢水温度1520—1530℃;控制浇铸过程塞棒吹氩量≤10L/min;结晶器液位波动±3mm等工艺措施。应用结果表明,轧坯角部拉裂缺陷率由原来的23．57％降至1．21％。     

中间包吹氩去除夹杂物的模拟研究

通过水模型模拟实验,选用苯胺模拟夹杂物,有机硅油模拟中间包渣,研究了中间包吹氩去除夹杂物的效果;通过刺激—响应法测定中间包吹氩RTD曲线,探讨了中间包吹氩去除夹杂物的过程和机理。研究结果表明:在中间包吹氩条件下,活塞区体积分数最大的吹氩位置不一定会得到最大的夹杂物去除效果,在注流区附近吹氩,不但可以提高气泡捕捉夹杂物颗粒的概率,而且促进了夹杂物颗粒相互碰撞长大,去除夹杂物效果更为明显。     

中间包吹氩技术的研究进展

讨论了中间包吹氩技术去除夹杂物的机理以及影响夹杂物去除率的因素,并综述了中间包吹氩时气液两相流体流动的数学模型,讨论了几种不同的中间包吹氩技术,指出了我国中间包吹氩技术的现状。     

Regional differences in suicide in Hungary in the light of registered cases of depression

Author made a revision on the theory published by Rihmer and alii in the year 1989. According to this theory the marked regional differences of suicide in Hungary are caused by the different discovery of the "endogen depression" (rate of diagnosed depression). So the lower is the diagnosis of depression the higher is the suicide rate in a given territory. They have seen a negative correlation between the number of working physicians and the suicide rates. Author made a reexamination on a correct database between 1985-1994. He has also made a study using the DSM-III-R diagnostic criteria in four counties of Hungary. His results deny the theory above mentioned. The rank-correlation of the number of GP and the suicide rates in Hungary in years 1985-1994 did not show correlation. So the underdiagnosis of the depressive disorders and the different number of GP are not the cause of the regional differences of suicide in Hungary.     

Role of clozapine in the occurrence of chromosomal abnormalities in human bone-marrow cells in vivo and in cultured lymphocytes in vitro

Bone-marrow chromosomes were examined from 38 mentally and physically retarded and two psychiatric patients who were being treated with a variety of neuropharmacologic drugs. Twenty of these patients used clozapine (Leponex). The clastogenic effects of clozapine in vitro were studied in the lymphocyte cultures of three patients--one free of hematologic disease and two who 6 months earlier had had agranulocytosis attributed to the use of clozapine. The mean frequency of cytogenetic abnormalities in the bone-marrow cells of patients who used clozapine was significantly increased (P less than 0.05). The two patients who had had agranulocytosis had a greater frequency of cytogenetic abnormalities in their cultured lymphocytes in vivo and in vitro than the patient free of hematologic disease. A clone with a 13/14 chromosome translocation was detected in one of the patients. As all patients received a number of drugs during the in vivo and in vitro studies no definite conclusions could be drawn regarding the role played by clozapine in the occurrence of chromosomal abnormalities.     

Efficacy of lomefloxacin in treatment of nonspecific inflammatory diseases and in prophylaxis of postoperative complications in urology

Clinical and bacteriological efficacies of lomefloxacin and ofloxacin were comparatively estimated in the treatment of 104 urologic patients with nonspecific inflammatory diseases and in 36 urologic patients for prophylaxis of inflammatory complications after surgical interventions. The majority of the urinary tract pathogens i.e. Enterobacteriaceae spp. and gramnegative nonfermenting bacteria were highly susceptible to both the fluoroquinolones. The clinical and bacteriological efficacies of lomefloxacin amounted to 94.4 and 80.7 per cent and those of ofloxacin to 92 and 79.2 per cent respectively. The prophylactic use of lomefloxacin and ofloxacin was efficient in 94.7 and 94.1 per cent of the cases respectively. The antibacterial prophylaxis in urologic patients should be applied not only at the period of surgical interventions but also during the early postoperative period.     

Difference in changes of plasma volume in two types of Goldblatt hypertension in rabbits

High plasma renin concentration (PRC) and hematocrit (Ht) were observed in hypertensive rabbits with one renal artery clipped and an intact opposite kidney (Group A), while rather low PRC and Ht in hypertensive ones with one renal artery clipped and the opposite kidney removed (Group B). Plasma volume (PV), blood volume (BV), and packed cell volume (PCV) were estimated in these two types of hypertensive rabbits, and also in sham-operated rabbits (Group C). In Group A, 4 weeks after clipping of a renal artery, PV was decreased and significant inverse correlations were observed between PV and the elevation of blood pressure and between PV and PRC. A significant correlation between PRC and the elevation of blood pressure was also found 4 and 12 weeks after the clipping. PCV was increased until 12 weeks after clipping. In Group B, PV was increased 1 and 4 weeks after clipping, then returned to the initial level. Ht was decreased 1 and 12 weeks, and PCV was decreased 12 weeks after clipping. These results would indicate that a high Ht seen in Group A was partly due to the decreased PV and partly due to the increased PCV, while, in Group B, a low Ht in early stage might be mainly due to the increased PV, but in the late stage, a decreased PCV appeared to play a role to lower Ht. PRC seems to be affected differently by PV in these two types of hypertension.     

PLC在高炉汽动式鼓风机监控系统的应用

鞍钢高炉15号鼓风机是VASi-9018型轴流式汽轮压缩机，通过技术改造，采用先进的电子控制技术，建成了全新的具有现代化水平的汽轮压缩机控制系统。     

Role of signal peptides in targeting of proteins in cyanobacteria

Proteins of cyanobacteria may be transported across one of two membrane systems: the typical eubacterial cell envelope (consisting of an inner membrane, periplasmic space, and an outer membrane) and the photosynthetic thylakoids. To investigate the role of signal peptides in targeting in cyanobacteria, Synechococcus sp. strain PCC 7942 was transformed with vectors carrying the chloramphenicol acetyltransferase reporter gene fused to coding sequences for one of four different signal peptides. These included signal peptides of two proteins of periplasmic space origin (one from Escherichia coli and the other from Synechococcus sp. strain PCC 7942) and two other signal peptides of proteins located in the thylakoid lumen (one from a cyanobacterium and the other from a higher plant). The location of the gene fusion products expressed in Synechococcus sp. strain PCC 7942 was determined by a chloramphenicol acetyltransferase enzyme-linked immunosorbent assay of subcellular fractions. The distribution pattern for gene fusions with periplasmic signal peptides was different from that of gene fusions with thylakoid lumen signal peptides. Primary sequence analysis revealed conserved features in the thylakoid lumen signal peptides that were absent from the periplasmic signal peptides. These results suggest the importance of the signal peptide in protein targeting in cyanobacteria and point to the presence of signal peptide features conserved between chloroplasts and cyanobacteria for targeting of proteins to the thylakoid lumen.     

CS1000在天铁烧结生产过程控制中的应用

结合天津铁厂烧结分厂二烧车间烧结过程控制的具体情况,介绍了分散型控制系统在烧结生产上的应用以及数据网上发布的一种方法。