冷轧带钢卷取过程内应力的逐层增量求解

 带钢卷取过程由于张力的作用会在钢卷内部产生内应力,内应力的大小和分布直接影响轧后钢卷塌卷和内凸等缺陷的产生。考虑钢卷径向和周向弹性模量的差异,以及径向弹性模量的非线性,根据平面轴对称弹性理论,推导带钢卷取过程中内应力的逐层增量求解方程,引入相应的边界条件得到了卷取任意层数时钢卷内每一层带钢径向应力增量和位移增量方程组。基于逐层增量求解方法研究了带钢厚度、卷取张力、卸卷对卷筒压力和钢卷内应力分布的影响,并与试验结果进行了比较,验证了提出方法的正确性。     

重卷拉矫机组卷筒结构的改进

<正>1问题的提出冷轧带钢精整线上的卷取机负责将处理后的钢带卷取成卷,其工作状态直接影响着机组的生产效率、产品的质量。卷筒是卷取机中最重要的部分,柳钢冷轧板带厂1号重卷拉矫机组卷筒为斜楔胀缩卷筒,主要由芯轴、扇形块、轴向拉杆、楔形滑块、卷筒轴头、胀缩缸及旋转接头等组成。带钢的卷取动作分两个过程:初始卷取阶段,带头由前方夹送辊驱动,通过转向辊将带     

热轧带钢卷取温度对卷后应力影响研究

基于闭口圆筒的平衡方程、协调条件和本构关系,建立了热轧带钢卷后自然冷却过程的热致变形场理论模型,系统研究了典型温度波动形式和发生区域,对比不同厚度规格带钢的卷后应力演化的影响规律。将带钢卷取温度波动归纳为3类型式:L型、V型和反Z型,考虑其发生在带钢的带头段、中间段和带尾段。模拟结果表明,热轧带钢卷后应力的变化主要受卷取温度波动的影响,温度波动的位置越靠前、产生温降的层数越少和温差幅值越大,钢卷层内应力降低幅值越显著;相同厚度规格的带钢,发生L型温降波动时,其卷后层内应力降低幅值最显著,V型和反Z型依次次之;不同规格的带钢,发生L型温降波动时,其厚度越厚产生层内应力的降低幅值越大,而对于V型和反Z型温降波动,带钢厚度对其层内应力变化几乎无影响。本文研究结果对于优化热轧带钢的卷取温度策略从而提升钢卷下机后质量具有参考价值。     

热轧带钢卷取塔形产生原因及防范措施

分析了热轧带钢卷取塔形产生的原因,经过对卷取过程中夹送辊、芯轴和助卷辊的速度控制,卷筒与轧机间的张力控制,侧导板控制,以及卷取区设备维护等方面进行改进后,卷取塔形问题有了很大改善。     

双机架炉卷轧机助卷辊故障分析处理

昆钢板带厂热轧车间双机架可逆式炉卷轧机的助卷辊是地上卷取机的关键设备之一,其功能是将带钢导入到卷筒周围以确保带钢准确地卷取到卷筒上。热轧车间共有三套助卷辊,分别是一号,二号,三号。自投产以来,由于助卷辊控制系统故障,曾多次影响热轧车间的正常生产。本文针对助卷辊典型故障作分析并提出应急处理方法和改进措施。     

热轧带钢纵向亮带产生原因分析

根据热轧带钢表面出现的纵向亮带特征及发生规律,结合热轧生产过程工艺特点,分析了其产生的主要原因是带钢与卷取张力辊的局部接触,在张力辊压力、张力辊与卷筒间的张力共同作用,使接触区域的带钢发生塑性变形造成的。并提出了消除缺陷的措施。     

冷轧带钢卷取过程中受力与变形研究

带钢卷取和卸卷两道工序由于卷筒约束的变化,两种状态下钢卷的内部应力场存在变化,尤其是在卷芯部位应力场的变化较为显著,这也是带钢头部存在多种质量缺陷的区域.基于现场实测和紧密系数的实验研究,通过卷取过程应力场的差分求解以及卷取结束后卸卷过程中机械应力和热应力耦合应力场的差分法求解,获得了钢卷内部应力场的分布规律,为生产现场预防及控制卷取和卸卷过程中产生的各类缺陷提供了有效的技术对策和理论依据,使机组的产品板形质量和成材率明显提高.     

1．5t热轧带钢无芯卷取机的设计要点

热轧带钢无芯卷取机卷取带钢卷重可达 1 .5t,且卷取带钢卷质量好。介绍了该卷取机的设计要点     

热轧带钢卷形控制分析

热轧带钢卷形问题是影响带钢质量的重要因素。本论文针对热轧带钢卷取过程中产生的卷形问题,从控制模型及工艺操作、设备管理因素等方面对各类卷形进行分析和研究,解决卷取卷形不良问题,提高成材率和经济效益。     

钢带的卷取计算

1、绪言冷轧带钢轧机、热轧带钢轧机及带钢连续酸洗设备等过程作业线的尾部或始端,要使用卷取机和开卷机。卷取机的卷筒在卷取过程中,由于钢带的张力作用,随着卷取的     

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.     

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。     

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)     

Comparison of rates of infection of two methods of emergency ventricular drainage

The rates of infection of two methods of external ventricular drainage in use at Atkinson Morley's Hospital--namely, (a) percutaneous drainage with Rickham reservoirs and (b) tunnelled ventriculostomies--were compared in this retrospective review. Percutaneous drainage of CSF with Rickham reservoirs was associated with a 27% rate of infection as identified by positive microbiological cultures; tunnelled ventriculostomy catheters had a 10% infection rate. The difference in the infection rate between the two methods was statistically significant (P < 0.015). Other variables examined, including the age and sex of the patients and the reasons for ventricular drainage, were not associated with an increased rate of infection. Most infections from either method were caused by a coagulase negative staphylococcus. The average duration of ventricular drainage before identification of positive cultures was 5.7 days for Rickham reservoirs and 6.0 days for ventriculostomies.     

浅析《野草》的版画特征

鲁迅先生一生热爱美术作品,对版画中木刻兴趣尤甚.<野草>作为其"写心之作",亦呈现出一些与木刻版画一致的审美特征:一是具有木刻版画的色彩特征,多对比、多冷色,有阴郁的美感;二是具有木刻版画的力度特征,环境描写、人物刻画处处刀锋毕现,遒劲有力,有一种"力之美".     

四辊破碎机车刀架的改造

针对四辊破碎机车刀架车削中存在的几个问题,详细介绍了电动车刀架的结构和工作原理,建立主要设计参数的数学表达式,并进行适当的分析。改造后,这种电动车刀架运行平稳、可靠、方便、省力,取得了预期的效果。