冷轧四辊轧机辊间接触应力与工作辊边裂失效分析

研究冷连轧机组辊系受力分布状态,揭示冷轧四辊CVC连轧机工作辊边部环裂产生原因。以某厂轧辊边部剥落案例为基础,通过对轧辊剥落形貌观察,硬度检测分析,并借助有限元仿真计算对工作辊在服役中的受力分布状态进行了计算。结果表明接触应力最大位置应为与支承辊端部倒角根部,最大应力达到1000MPa。工作辊边部环裂或局部剥落主要与工作辊横向移动在辊身端部受到较大接触挤压应力有关;在高周循环挤压应力作用下,轧辊次表面形成微裂纹,随裂纹扩展最终导致轧辊失效。     

UC冷轧机中间辊端部辊形设计研究

为优化轧机的板形控制性能,提高产品的板形质量,针对UC冷轧机研究了中间辊端部辊形曲线的设计方法,以二维变厚度有限元程序为辊形设计的工具平台,通过建立UC轧机辊系弹性变形有限元模型并进行数值仿真计算,研制出了新的多项式辊形曲线.仿真计算结果表明,新中间辊端部辊形可以提高弯辊调控功效,扩大承载辊缝调节域,改善辊间接触压力分布,研究结果为生产实践提供了可以借鉴的理论指导.     

济钢3200mm四辊粗轧机机架辊受力分析

济南钢铁集团总公司宽厚板厂3200mm四辊粗轧机,系由荷兰引进的二手轧机改造而成,原为精轧机,在我公司改造为粗轧机后,将原来适应精轧机的机架辊改造为适应粗轧机的机架辊.由于设计过程中,对机架辊的受力状态缺乏全面的分析,机架辊一端固定在垂直预埋板上,基础受力状况为垂直方向36.8t,另一端利用轧机地脚螺栓固定,致使在投用几个月后,就出现了预埋板脱落现象,被迫停产加固.为使加固后的机架辊适应粗轧机负荷变化大的要求,我们对粗轧机轧制过程的受力状况进行了认真的分析,以指导机架辊新的加固方案的实施.     

空气轴承式板形辊边部辊环标定新方法

根据印尼PT-Alumindo冷轧厂空气轴承板形辊实际生产时边部辊环的实际受力情况,采用重心偏移法对辊环进行了标定,得到边部辊环受力的标定曲线。该板形辊在线投入使用时,带材边部根据由此标定曲线得出的边部板形信号真实反映了实际板形,提高了边部板形控制精度。     

镀锌支承辊掉肩原因分析及对策

镀锌支承辊掉肩严重影响生产的正常运行,如修复不当,将直接导致支承辊报废或上机发生断辊等恶性事故。从轧辊受力、辊形磨损和轧辊使用等角度分析了引发支承辊掉肩的具体原因,并制定了相应对策。认为工作辊轧制中位线与支承辊中位线不重合是造成支承辊操作侧单侧掉肩的根本原因。通过优化支承辊端部辊形曲线、修订轧辊使用制度等措施,支承辊掉肩问题得到有效控制,同时节约生产成本50余万元。     

热连轧机支承辊的辊型优化研究与应用

总结并推导了热连轧机支承辊的主要辊型公式,并通过辊系受力有限元计算,对比分析了不同支承辊辊端倒角曲线和倒角参数对辊间接触应力轴向分布的影响;在此基础上,综合考虑热连轧机的设备参数、工艺参数等条件,以提高辊间压力轴向分布均匀性、弯辊力调控效果和出口板形质量为优化目标,开发了支承辊辊型优化计算程序。针对某热连轧机支承辊在实际生产中存在的问题,计算得到两种优化的支承辊辊型曲线;对比优化辊型支承辊上机使用前后各1年的数据,新辊型支承辊下机辊面状态明显改善,辊型保持率提高,边部硬化程度减弱,从而进一步优化了支承辊的受力和磨损状态,提高了支承辊的使用安全性。     

拉矫机工作辊异常磨损和轴头烧损的对策

为了解决拉矫机工作辊服役周期短的问题,在研究拉矫机工作原理的基础上,对工作辊啮合量的合理使用范围进行了深入探讨,针对生产中出现的工作辊异常磨损现象,通过表面纳米涂层处理,延长了工作辊的使用寿命;针对工作辊轴头烧损现象,通过分析工作辊端部的受力变化,结合分析量化了拉矫机支撑辊和工作辊之间的间隙,最终解决了轴头的烧损难题。     

热镀锌机组沉没辊系受力模型及影响因素

热镀锌机组沉没辊系在锌锅内工作状态下受力情况复杂,受外界影响较大。充分考虑热镀锌机组设备与其工艺特点,首先分析沉没辊系在工作状态下受力情况,分别建立矫正辊插入量与包角的关系式、基于辊面锌渣沉积厚度的辊面摩擦因数经验模型。随后采用条元离散法建立沉没辊系辊面接触压力、摩擦驱动力矩模型,基于简支梁模型确定沉没辊系轴端支撑力、轴端摩擦阻力矩模型。最后将沉没辊系受力模型应用于国内某热镀锌机组镀锌工艺段,以典型规格带钢确定沉没辊系受力影响因素,并依据机组实际工况及板形要求来确定生产工艺参数的5种不同水平,来分析其对辊系受力状态的影响规律,为沉没辊系工艺优化提供指导依据。结果表明,4种工艺参数对辊系接触压力及摩擦力矩影响都存在差异性,矫正辊插入量与辊面接触压力呈现非线性关系;带钢张力对各辊接触压力影响程度不同,其中沉没辊受到的影响最大,而其余两辊受到张力几乎不影响;辊面平均摩擦因数、带钢速度对辊的接触压力几乎不影响;辊系摩擦驱动力矩、轴端摩擦阻力矩随着矫正辊插入量及辊面平均摩擦因数增大都呈现出不同程度增大。带钢张力与沉没辊摩擦驱动力矩、轴端摩擦阻力矩呈线性变化关系,而带钢张力对其余两辊影响很小。带钢...     

首钢3500 mm中板轧机辊型研究与应用

采用影响函数法建立轧辊的弹性变形解析模型,针对首钢3 500 mm中板轧机在轧制过程中,支承辊端部出现剥落或掉肉现象,根据首钢中板厂的轧制工艺,分析了不同板宽、不同轧辊辊型、不同轧辊端部倒角以及直倒角参数对辊间压力分布的影响规律.研究结果表明,在轧制能力范围内,轧件越宽,轧辊采用凹辊型可以使辊身部的辊间压力分布更为均匀;倒角的选择和改变直倒角的参数都会相应地改变端部的应力集中现象.研究结果为该轧机的辊型的改造和配置以及提高轧辊寿命提供了理论依据.     

UCM轧机转向辊控制模型与应用

 在板形测量系统中,板形辊边部传感器受力状态与转向辊受力弯曲有直接关系。为了得到准确的板形测量值,通过研究ABB板形辊的板形检测原理,分析了边部传感器在带钢张力作用下的受力状态,给出了转向辊受力弯曲的数学模型,并成功应用于1450冷连轧机上。研究结果表明,该模型用于ABB板形辊板形测量系统中,实现了板形精确测量。     

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.