GCr15轴承钢铸坯表面渣沟缺陷的改进措施

分析了300mm×360mm GCr15轴承钢铸坯表面渣沟缺陷的原因,对连铸工艺和结晶器保护渣的理化指标进行调整后,彻底解决了铸坯表面的渣沟缺陷。     

中碳钢连铸小方坯表面缺陷与保护渣性能选择

首钢第二炼钢厂160mm×160mm小方坯连铸使用高碳钢用FRK-45型保护渣生产碳含量为0．35％-0．50％的中碳钢时,大量连铸坯表面出现纵裂和横向凹坑。通过降低连铸机拉速、提高保护渣碱度及延缓保护渣熔速,改善了连铸坯坯壳与结晶器壁间的渣膜传热,使连铸坯的表面缺陷得到了有效控制。     

保护渣特性和连铸工艺参数对圆铸坯表面质量的影响

综合分析了连铸 3种圆铸坯的保护渣特性和连铸工艺参数 ,得出保护渣粘度 η和拉速VC 对铸坯表面质量有明显影响 :当Φ2 1 0mm、Φ2 70mm、Φ3 1 0mm圆坯的 η·V2C 值分别为 3 0、8、4泊·(m min) 2 时 ,圆坯表面缺陷指数最低     

包晶钢连铸坯表面纵裂与保护渣性能选择

 某钢厂宽厚板250 mm×1 820 mm连铸机使用包晶钢类型MB-59型保护渣生产[w(C)]为0.120%～0.150%钢种时,连铸坯表面出现大量纵向裂纹与皮下裂纹缺陷。通过提高保护渣碱度,降低保护渣黏度,改善铸坯坯壳与结晶器壁之间渣膜传热等技术措施,使铸坯的表面裂纹与皮下裂纹缺陷得到了有效控制。同时,对浇注[w(C)]为0.090%～0.120%钢种时采用MB-59型保护渣连铸坯表面无裂纹的原因进行了探讨分析,认为由于选分结晶,优先凝固的坯壳中碳质量分数低于钢液原始碳质量分数,使优先凝固的坯壳中[w(C)]实际已经小于0.090%,不再属于裂纹敏感性强的包晶钢范围,因此表面质量较好。     

Cr13型不锈钢小方坯连铸结晶器保护渣试验研究

针对Cr13型不锈钢在三机三流全弧形连铸机连铸150mm×150mm小方坯,研究连铸结晶器保护渣的配方,同时调整连铸拉坯工艺,降低因保护渣引起的铸坯表面缺陷。在生产使用现有保护渣的基础上,设计多个保护渣,经实验室性能测试及生产现场拉坯试验,确定适应生产的保护渣主要性能参数为:二元碱度R=0.81,半球点温度T半=1164℃,粘度(1300℃)=6.6P,而且该保护渣仍有改进的空间。     

铸坯喷丸工艺对430铁素体不锈钢卷板表面质量的影响

430钢连铸板坯经喷丸处理后可以去除连铸坯表面原始铁鳞与保护渣残留,铸坯平均振痕深度降低0.13 mm。喷丸处理铸坯经加热炉加热后生成的氧化铁皮结构与基体存在明显界面,在热轧与酸洗过程容易去除,避免了夹渣与氧化残留造成的冷板表面粗糙条纹类缺陷,酸洗板表面粗糙度由3.15μm降低至2.78μm,冷板粗糙度由0.047μm降低至0.041μm,冷板表面质量接近修磨工艺。430不锈钢铸坯喷丸工艺可替代修磨工艺。     

奥氏体不锈钢连铸圆坯表面质量的控制

针对奥氏体不锈钢连铸圆坯生产中出现较严重的纵裂、结疤、皮下夹渣等表面缺陷,经过试验对比和分析研究,找出了产生上述缺陷的主要影响因素.通过合理控制钢水浇注温度、选用适宜的连铸保护渣及浸入式中包水口,大大减少了不锈钢连铸圆坯的表面缺陷,各种缺陷比例均控制在4%以下,铸坯表面质量得到明显改善.     

连铸坯表面缺陷在圆钢轧制过程中的演变规律研究

选取表面存在划伤、渣沟、结疤的连铸坯进行定向轧制,并通过在铸坯表面人工预制裂纹的方法,利用酸洗、顶锻、金相及扫描电镜等手段,分析了铸坯缺陷在轧制φ20～60 mm圆钢过程中的演变规律及对应关系,总结出了不同产品规格对连铸坯表面缺陷的要求.结果表明,划伤、结疤、裂纹缺陷的深度遗传性较强,轧制圆钢规格越大,对铸坯表面要求越...     

小方坯不锈钢用保护渣的研制

简述了结晶器保护渣在连铸过程中的重要作用和2Cr13在连铸过程产生表面凹陷的机理。使用物化性能适宜的保护渣可以改善初始坯壳的传热与润滑,控制铸坯表面凹陷的产生。在实验室研究的基础上,研制出了适合于断面为150mm×150mm、拉速为1.0~1.5m/min的2Cr13不锈钢连铸结晶器颗粒保护渣。试验证明2号保护渣性能良好,2Cr13连铸坯因表面凹陷产生的返修率由20%下降到5%。     

攀钢360mm×450mm大方坯连铸关键技术开发

简述了攀钢自主开发的360 mm×450 mm大方坯连铸集成技术及其效果.通过研究开发合理的连铸二冷技术、凝固末端动态轻压下技术和结晶器电磁搅拌技术,提高了铸坯内部质量,解决了大方坯中心疏松、中心偏析、内部裂纹等内部缺陷较严重的技术难题;通过研究设计合理的结晶器结构和冷却工艺制度,以及开发性能优良的连铸保护渣,提高了铸坯表面质量,减轻了大方坯表面凹槽和凹坑缺陷.两年多的生产实践表明,攀钢360 mm×450 mm大方坯连铸机生产的铸坯,中心疏松、偏析、缩孔、裂纹等内部缺陷的评判级别均小于1.0级的综合比例达到99.03%,中心碳偏析指数为1.01～1.05(平均1.03),铸坯表面无缺陷率平均达到99.54%.研究成果为促进攀钢品种结构调整和开发高质量、高性能、高附加值产品提供了重要的技术支撑.     

转炉炉壳热应力分析

根据实际转炉建立实体模型。以有限元为手段,考虑了炉衬和炉壳材料的物性参数随温度变化的特点和炉衬与炉壳之间膨胀间隙,计算了转炉炉壳在温度载荷和炉衬膨胀压力同时作用下的热应力。所得结果可为转炉炉壳设计提供依据。     

焦炭热性能指标意义浅析

通过对焦炭在高炉内的历程及其变化规律的剖析,阐述焦炭热性能指标的意义,形象地把焦炭在高炉内的损耗分为三部分(M1,M2,M3)。指出M2对焦比及焦炭价格有一定的指导作用。     

Results of treatment of cancer of the cardia

Cancer of the cardia is traditionally discussed with cardiac cancer of the lower portion of the esophagus and upper gastric cancer invading the esophagus, and the specific characteristics of cancer of the cardia have never been clearly defined. We reviewed the outcome of 172 patients with adenocarcinoma of the cardia who had undergone radical surgery between 1949 and 1994 in the Division of Gastrointestinal Surgery of the Cancer Institute Hospital. The centers of the tumors were located within 2 cm above and below the boundary between the esophagus and the stomach, and their longitudinal diameter was less than 8 cm. We divided the patients into an early period (1949-1979; n = 79) and a late period (1980-1994; n = 93), and focused on the historical transition. There were no differences in patient gender or histology between the two periods. However, the late period was associated with fewer cases of esophageal invasion and shorter longitudinal diameter, as the age of the population advanced. The number of advanced cancers such as the localized and infiltrative type had decreased, and early cancer and early clinical stage had become more common, but despite the fact that the number of early cancers had increased, extended dissection, such as thoracic and paraaortic lymph node dissection, was performed more frequently. By clinical stage, the long-term outcome markedly improved in Stage I patient in the late period, and tended to improve in Stage II and III patients. This appears to have been attributable to the prevention of micrometastasis by extended dissection, although the number of early cancers is another major potential cause. There were no differences in the outcome of Stage IV patients between the two periods, and further advances in multimodality therapy must be awaited. The range of resection is basically proximal gastrectomy, and if there are adequate indications, the prognosis is favorable. In view of the status of lymphatic flow and lymph node metastasis, and long-term results, lateroaortic lymph node dissection is important. Since the number of early cancer patients has been increasing, if intraabdominal recurrence is prevented, intrathoracic lymph node dissection will contribute greatly to the outcome of such patients.     

The effect of amount of possession of the trait of hostility on accuracy of perception of hostility in others.

Some theories of personality hold that an individual's perception of others is influenced by his own personality characteristics; more specifically, that a trait of low social value will be projected more into others, and that insight into the possession of these characteristics reduces this distortion. These 2 hypotheses were tested by having a group of college students rate each other (including themselves) on degree of friendliness or hostility. Agreement with group rating about self yielded the insight score. In general, the hypotheses were supported; the "friendly" Ss were most accurate in their perception of others, and insight was positively associated with accurate perception. From Psyc Abstracts 36:04:4HL16M. (PsycINFO Database Record (c) 2010 APA, all rights reserved)     

Effect of antibiotics of chemotaxis of human leukocytes

The effect of 20 different antibiotics on chemotaxis by human neutrophils was studied. Human leukocytes incubated with chloramphenicol, rifampin, sodium fusidate, and tetracyclines in vitro showed markedly depressed migration. The mechanisms by which these antibiotics affect leukotaxis are discussed.     

Quality of life of relatives of mental patients

Usage of quality of life of psychiatric patients' relatives as the parameter of estimation of the quality of psychiatric care is considered. By means of standard questionnaire elaborated by the authors as well as by means of both individual and group conversations the quality of life was analyzed in 40 relatives which lived together with psychiatric patients. Different spheres of their life and difficulties (financial, social-psychologic, production) were examined in families with such patients. The defects of psychiatric care that had direct influence on the quality of life of the psychiatric patients' relatives are outlined.