超低碳钢板坯夹杂物的量化分析

为定量分析现有工艺下超低碳板坯的夹杂物能否满足冷轧板表面质量要求,使用金属中夹杂物原位快速自动分析仪(Aspex)定量研究了超低碳钢板坯中夹杂物的分布、种类、尺寸。发现铸坯中夹杂物在铸坯断面上夹杂物分布较均匀。正常坯有极个别簇状夹杂物尺寸在50~100μm。切头和尾坯存在少量大于100μm的簇状夹杂物。RH处理过程无论是否吹氧,在脱碳结束时活度氧相当,铸坯夹杂物总量和尺寸也基本相同。现有工艺生产超低碳板坯可以满足用于冷轧板表面质量的要求,但切头和尾坯不能用于冷轧薄板生产。     

IF钢铸坯皮下夹杂物与钩状坯壳的特征分布

<正>超低碳IF钢(无间隙原子钢)主要用于汽车面板和白色家电板,因此对表面质量有着较高的要求。IF钢冷轧板主要的表面质量问题就是线性缺陷,而坯壳所捕获的保护渣夹杂物、簇群状氧化铝夹杂物、"气泡+Al_2O_3"夹杂是造成这种线性缺陷的主要因素。夹杂物容易在超低碳钢铸坯的近表层聚集,为了消除由此导致的表面缺陷,提高生产的稳定性,生产出高品质的冷轧薄板,需要对铸坯进行表面清理。     

冷轧板表面夹杂缺陷成因及控制

针对首钢京唐冷轧板出现的表面夹杂缺陷,在对冷轧板取样电镜分析的基础上,得出铸坯浇铸过程保护渣卷渣以及铸坯中的Al2O3夹杂物是冷轧板条痕缺陷产生的主要原因。通过采取延长RH脱氧合金化后的纯循环时间、采用自动液面控制、取消抖棒操作、选用合适的下渣模式、提高保护浇注效果及提高保护渣黏度等技术措施后,冷轧板的夹杂缺陷得到了有效控制,因夹杂缺陷引起的协议品率由0.83%降至0.30%左右。     

M-EMS对马氏体不锈钢连铸坯质量的影响

根据工业试验结果，分析了结晶器电磁搅拌（M-EMS）对马氏体不锈钢连铸坯的中心疏松、等轴晶率、缩孔及表面质量的影响，并对电磁搅拌对铸坯凝固的影响机理进行了探讨。结果表明：经结晶器电磁搅拌后，当平均磁感应强度B为0．066T时，铸坯中心等轴晶率平均达到了50％，最高达57％，中心疏松均在1.5级以下，中心缩孔90％在1．0级内；铸坯表面质量由使用二冷区电磁搅拌的85％提高到97％，为结晶器电磁搅拌工艺参数的优化及设计提供了一定的依据。     

电磁制动对坯壳冲击和弯月面温度影响的研究

本文采用数值模拟和现场试验研究了电磁制动对CSP结晶器内坯壳冲击和弯月面温度的影响。围绕电磁制动数值模拟，提出了钢水对结晶器内壁或铸坯初凝壳冲击和冲刷作用的半定量分析方法。数值模拟显示：电磁制动使钢水注流对结晶器窄边（最大）冲击位置上升40％，上升流的冲刷强度下降了86％，下降流的冲刷强度下降了10％，这有利于避免发生铸坯初凝壳被钢水热流重熔等现象，从而减少铸坯横裂等凝固缺陷；由现场对比试验知，使用电磁制动使弯月面钢液温度上升5．8℃．利于结晶器内钢水表面的化渣。     

中厚板连铸坯表面无缺陷生产实践

山钢股份济南分公司炼钢厂投产的6#板坯连铸机铸坯表面质量不稳定,表面裂纹、夹渣等缺陷比较严重,影响轧制质量。通过外弧角横裂纹控制、铸坯表面夹杂缺陷控制等措施,中厚板连铸坯表面质量得到了明显改善,铸坯外弧角横裂缺陷发生率由25.2%降到了0.03%以下,钢板夹杂缺陷率由月均1.32%降低至0.13%以下。     

IF钢铸坯表层大型夹杂物分布及来源研究

针对IF钢铸坯表层大型夹杂物问题,通过大样电解法研究了电磁制动、拉速对IF钢铸坯表层大型夹杂物数量及分布的影响,结合扫描电镜、数值模拟等方法讨论了大颗粒夹杂物的类型和来源。结果表明:未开电磁制动时,夹杂物在铸坯边部有聚集现象。拉速提高铸坯边部夹杂物聚集减弱,1.5m/min拉速较1.2 m/min低拉速减弱17%,夹杂物总量也降低了5.3%;1.2 m/min拉速开电磁制动,夹杂物平均数量减少52.0%,铸坯宽度方向夹杂物分布趋于均匀。Si O2系复合夹杂物因表面张力小是IF钢中主要的大型夹杂物类型,其次有Mg O系、Al2O3系、Ti O2系复合夹杂物;耐火材料的冲刷侵蚀、二次氧化、水口结瘤物是铸坯中大型夹杂物的来源。     

IF钢表面夹杂缺陷的研究及控制技术

介绍本钢IF钢夹杂的形貌、组成以及在冷轧板上的分布情况,分析了夹杂形成原因。对转炉炼钢工序、精炼工序和连铸工序的工艺参数进行优化和建立合理的铸坯管理办法使本钢IF钢表面质量大幅提升。     

F钢铸坯皮下夹杂物与钩状坯壳的特征分布

<正>超低碳IF钢(无间隙原子钢)主要用于汽车面板和白色家电板,因此对表面质量有着较高的要求。IF钢冷轧板主要的表面质量问题就是线性缺陷,而坯壳所捕获的保护渣夹杂物、簇群状氧化铝夹杂物、"气泡+Al2O3"夹杂是造成这种线性缺陷的主要因素。夹杂物容易在超低碳钢铸坯的近表层聚集,为了消除由此导致的表面缺陷,提高生产的稳定性,生产出高品质的冷     

IF钢冷轧板表面条状缺陷成因及控制

条状缺陷是IF钢冷轧板常见的表面缺陷之一,针对邯钢IF钢冷轧板表面出现的条状缺陷,分析了该类条状缺陷的成因,并提出了合理的控制措施。通过SEM-EDS分析发现条状缺陷内部存在大量的小尺寸Al_2O_3颗粒,分析其来源于铸坯中大型Al_2O_3夹杂物。对不同浇注阶段铸坯进行SLIME法大样电解并采用SEM-EDS分析其大型夹杂物类型,发现在交接坯和换水口坯中存在较多的大型Al_2O_3夹杂物,分析其来源为水口结瘤物。综合分析后得出此类条状缺陷成因是水口结瘤物脱落被卷入结晶器,并在铸坯中形成大型Al_2O_3夹杂物,进而在冷轧板轧制过程中形成表面条状缺陷。     

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。     

Concept of freedom of infection of animal flocks

Totally negative results of epidemiological investigation of random samples do not prove the absence of the infection as the pathogen may be restricted to only a few animals in the herd for a long time. The statement "absence of infection" is critical for such situations. The question is raised, whether the statement "absence of infection" should be generally avoided. Classification of herds and flocks according to the prevalence of the pathogen would be more valid for the implementation of control measures.     

显微维氏硬度测量不确定度评定

对显微维氏硬度测量不确定度进行评定，建立了不确定度计算的数学模型，确定了影响实验结果的各项因素，计算出了各因素的标准不确定度，得出结果的扩展不确定度，并给出最终测量结果的表达式。     

Comparison of the results of surgical and conservative treatment of fractures of the diaphysis of the tibia

In this paper is treated the fundamental problematic of the fracture of the diaphysis of the tibia and the therapeutic results after the conservative and operative treatment are confronted. Among 518 patients with 433 open fractures and 35 with closed fractures of the diaphysis of the tibia, successful treatment of more 2/3 was obtained in the period from 1968 to 1972. Following our casuistics and literature, whose results are similar, we find out that the average total treatment of the osteosynthesis of the fracture of the diaphysis was shortened for 2,5 months depending upon the type and the localisation of the fracture. Apolied methods of the operative and conservative and conservative treatment in relation to the velocity of the medical cure as well as to the extreme anatomical-functional results are analised. We noticed that osteosynthesis, made by the intermedullary nail and the extension of the canals or by a small AO table, by the achieved stability makes conditions of immediate motions and an early rehabilitation. Because of that it gives the best functional results.