高性能均质靶板用钢的钢锭凝固数值模拟与生产实践

高性能均质靶板用钢,采用40 t EAF-LF-VD-模铸20 t钢锭—锻造加热工艺流程生产.使用ProCAST铸造模拟软件对高性能均质靶板用钢模铸20 t钢锭的凝固过程进行了数值模拟,分析了钢锭纵向截面疏松缺陷的分布区域和程度,得到大型锻造用钢锭与锻造材料探伤缺陷形成原因,可为生产提供指导依据.结果表明,通过控制模铸过热度和添加冒口发热剂的方法,使高性能均质靶板用钢的锻造用钢锭质量得到提高,在锻造后探伤缺陷得到有效控制.     

提高钢锭质量的实践与探讨

本文简要说明了近年来我厂钢锭取得的成绩，扼要分析了钢锭穿孔、铜裂缺陷产生的原因和应采取的对策，重点探讨了目前制约我厂钢锭质量的探伤缺陷产生的原因和应采取的措施以及生产实践取得的成果。     

12Cr2Mo1VR钢锭成材钢板尾部分层缺陷原因简析

通过金相显微镜、扫描电镜,对探伤不合格的12Cr2Mo1VR钢锭成材钢板尾部分层缺陷进行分析,从夹杂物尺寸、成分及缺陷处组织等方面排查分层缺陷产生原因。结果表明：在钢板厚度中心存在源于钢锭的氧化物夹杂以及夹渣,在轧制过程中导致分层,造成钢板探伤不合格。采取延长工艺的执行时长、精准控制精炼毕钢液中酸溶铝含量和氩气保护浇注等改进措施,有效改善了钢板的内部质量,保证了探伤合格率。     

特厚板尾部面积缺陷的成因分析

研究了钢锭成材特厚板的尾部超声探伤缺陷的性质,介绍了模铸法生产大钢锭过程中,炉外精炼工艺、浇铸工艺以及浇铸用辅助材料对大钢锭内部质量的影响。通过对模铸用辅助材料、成品样及汤道样的能谱及化学分析可知,尾部面积缺陷的主要来源应该是钢液中的脱氧产物Al2O3以及少量没有被渣料吸附的复合化合物。针对缺陷的形成原因,制定了有效的改进措施,每月探伤的钢板尾部面积缺陷发生率由1.25%~2.25%降低到0.38%,最高降低幅度达到83.11%。     

钢锭成材钢板常见缺陷定性及改进措施钢锭成材钢板常见缺陷定性及改进措施

以舞钢公司扁锭生产低合金系列特厚钢板探伤不合的缺陷为研究对象,根据钢锭的凝固理论、钢板缺陷各项检测分析以及大钢锭锭型数据模拟优化,从钢水质量、控制手段、锭型设计各方面着手,分析常见缺陷的性质及产生原因,提出了解决扁锭内部缺陷的措施。     

电渣H13钢锭探伤缺陷分析

通过对1．2t电渣重熔钢锭探伤缺陷样品的低倍检测、金相组织检测以及裂纹部位能谱分析，指出探伤缺陷是由于电渣重熔过程熔速过快引起合金碳化物偏析，造成的沿晶裂纹而产生。调整了重熔工艺参数，纳入工艺规程后生产的产品未再发生此种缺陷。     

船用曲柄85～95t S34MnV钢锭的生产实践

曲柄用钢S34-MnV的生产流程为100 t Consteel电弧炉-LF-VD+VC（真空浇注）-铸锭工艺。运用扫描电镜和数值模拟对$34MnV钢锭缺陷部位钢样进行了观察和分析,得出造成曲柄探伤不合的原因为钢锭沉积锥处有大量非金属夹杂物富集。通过精炼前喂2 m/t铝线深脱氧、终脱氧喂Ca-si线,控制钢中夹杂物类型,调整渣系、优化钢锭模结构等优化工艺措施,减轻了钢锭的沉积锥缺陷,使钢锭废品率由原来的21%降低至6%,钢锭尾部氧含量由原来的23×10^-6降低至12×10^-6。     

钢锭本体帽口的试验研究

基于帽口高度对钢锭内部质量的影响,开展了钢锭本体帽口的试验。研究结果表明：本体帽口对提高钢锭内部质量、提高钢板探伤合格率有着非常明显的作用。但钢锭最终质量还受前步冶炼、精炼、真空处理等工艺的影响,单靠采用本体帽口不可能完全解决钢锭探伤问题。     

一种合金焊丝模铸锭中心孔洞的成因和措施

高强度合金焊丝钢广泛用于工程机械行业,具有残余元素低、纯净度高的特点,氢、氧、氮气体元素含量均要求严格,国内该系列焊丝材料主要依赖进口。为了进一步开拓系列高端焊丝钢市场,开发了新型高强度合金焊丝钢。生产过程发现模铸钢锭轧制后探伤不合格,取样发现初轧坯横截面低倍中心出现孔洞缺陷,影响材料质量。通过低倍试验和EPMA分析结合材料成分采用Thermo-Calc软件计算固液相线,分析发现钢种固液线差值相对较小是导致钢锭中心孔洞的主要原因。采用优化钢液浇注过热度和模铸浇注时补缩控制,避免了钢锭中心孔洞缺陷的产生。     

提高模具钢超声波探伤合格率实践

模铸模具钢自开发以来,受到市场用户普遍认可,具有较高的市场占有率。但近几年随着市场竞争的加剧,用户对质量的要求越来越高,超声波探伤合格率不高成为市场开拓的一大阻力。分析模铸生产模具钢超声波探伤不合格的原因,结合缺陷类型和生产过程控制实绩,并通过对钢锭凝固机理的研究,从转炉炼钢、炉外精炼、钢水浇铸及模铸使用的耐辅资材等各环节采取了有效的针对性措施,减少钢水内生夹杂物,控制浇铸过程中产生的外来夹杂物,提高钢水纯净度,改善钢锭内部组织,通过生产实践验证,取得了较好的效果。     

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.