[Mn]/[Si]对小方坯表面夹渣物的影响

主要分析了[Mn]/[Si]对小方坯表面夹渣物的影响,提出了防止表面夹渣物产生的措施经实践检验,随着[Mn]/[Si]的提高,铸坯表面夹渣明显减少。     

提高Mn／Si改善连铸生产的研究应用

针对夹渣率高对连铸生产造成的不良影响,通过分析连铸生产工艺状况,确认脱氧产物是影响铸坯夹渣的主要因素,在提高Mn／Si,优化脱氧工艺后,连铸坯质量和连浇率有了明显提高。     

南钢DF钢夹杂物分析研究

对南钢转炉厂生产DF钢中的夹杂物进行了研究，结果表明现有工艺制度下吹氩精炼效果不明显，氩后钢中的夹杂物含量为865．78mg／kg；大于300μm的夹杂物，主要成分为Si—Al，或Si—Al—Mn；80～300μm夹杂物，主要成分为Si—Al-Mn，且Si较高，Mn较低；小于80μm的夹杂物，主要成分为Si—Al—Mn，并且含Mn较高：改变钢液脱氧制度及控制吹氩搅拌，可使氩后钢中及铸坯中的夹杂物含量分别降低到203．38mg/kg、59．8mg／kg。     

70t直流电弧炉生产60Si2Mn钢中T[O]的控制

在70t直流电弧炉—LF—小方坯连铸工艺生产60S i2M n时,通过热装铁水及配加生铁提高电炉炉料的配碳量,提高电炉的终点碳,改进电炉出钢脱氧方法,降低钢中的溶解氧,采用合理的精炼渣系和精炼后的吹氩弱搅拌,加强保护浇注等措施,显著降低了60Si2Mn钢中的T[O]含量,使得成品的T[O]达到30×10-6,明显提高了60Si2Mn的疲劳寿命。     

红钢HPB235铸坯表面夹渣原因分析

2008年9月，昆钢红钢HPB235钢坯出现严重的表面夹渣，经过工艺研究和统计分析，找到了出现问题的主要原因是钢水【Mn】／【Si】低，钢水流动性差，生成了大量的高熔点氧化物浮渣，未能及时捞净，在结晶器弯月面处冷凝成团而形成。红钢据此采取相应的措施，铸坯质量明显改善。     

碳素结构钢钢渣改质后铸坯中大型夹杂物行为

通过夹杂物示踪等试验对北方某钢厂两种低成本碳素结构钢Q235D的大型夹杂物含量、种类、粒径、来源等进行了系统研究。结果表明:120 t转炉—CC工艺,稳态铸坯中T[O]平均含量为76×10-6、[N]平均含量为28×10-6、10 kg铸坯中大型夹杂物含量为31.3 mg;混浇坯T[O]平均含量为82×10-6、[N]平均含量为30×10-6、10 kg铸坯中大型夹杂物含量为38.8 mg。只含钢包渣示踪剂的夹杂物约占5%,只含中间包渣示踪剂的夹杂物约占22%,同时含钢包渣、中间包渣两种示踪剂的约占27%。120 t转炉—钢包渣改质处理—CC工艺,出钢温度较原工艺高15℃,5 kg/t改质剂、5 kg/t石灰随脱氧剂同时加入钢包,并大搅至出钢结束,盖上钢包盖后静吹12 min,然后静置20 min送至连铸。典型钢包终渣成分:43%Ca O,36%Al2O3,10%Si O2,6%Mg O,5%(Mn O+Fe O)。改质处理后钢中T[O]及大型夹杂含量均大幅降低,钢包顶渣改质剂的加入明显增强了钢渣对大型夹杂物的吸附能力,能做到一个浇次30炉不堵水口,改质处理作用显著。     

含硫易切不锈钢连铸保护渣的优化

含硫易切不锈钢SUS416要求铜中[S]高达0．25％-0．35％,[O]达到60-100ppm,结晶器内钢水弯月面处[S]、[O]含量更高,使得保护渣容易形成熔化不良的“絮状”渣团,导致铸坯表面出现严重的夹渣和针孔缺陷。针对该问题,研究了保护渣组成、渣型对浇铸状况和铸坯质量的影响。工业化试验表明,提高保护渣中粗石墨含量和降低保护渣容重,可有效抑制“絮状”渣团及其引起的铸坯缺陷,以获得表面质量优良的铸坯。     

进口富锰矿冶炼高炉锰铁[Si]低原因的研究

高炉锰铁中的硅来自焦炭灰分和部分锰渣中的SiO2。硅还原过程为SiO2-SiO2-[Si]。使用高Mn低SiO2的进口富锰矿，因其焦比低渣量少，造成锰铁[Si]低，因此它不仅提高锰含量而且提高货物等级。     

连铸非稳态430不锈钢铸坯大型夹杂物分析

为探究连铸非稳态对不锈钢大型夹杂物的影响,采用热轧超声探伤法研究了结晶器液面波动下430不锈钢连铸坯中大型夹杂物类型、来源、尺寸、数量、在铸坯中分布以及对冷轧板表面质量的影响等。结果表明,大型夹杂物主要包括4种类型,其中41.3%来源于结晶器水口结瘤物,38.7%为保护渣卷渣物,13.3%为精炼渣卷渣物,6.7%为内生夹杂物。水口结瘤物型夹杂物、精炼渣卷渣物和内生夹杂物一般在钢液出结晶器水口之前就已产生,主要集中在铸坯厚度方向距内弧面1/3到1/4处以及靠近窄面附近,保护渣卷渣物在结晶器内产生,存在某一区域聚集的情况。水口结瘤物型夹杂物属于脆性夹杂,且尺寸大,对冷轧板表面质量危害最大,因此应关注和减少连浇过程[Al]、[Mg]、[Ti]、[Ca]等残余活泼元素含量和钢水温度的波动,避免水口结瘤物结构变化产生大型夹杂物。通过热轧探伤法可获取连铸坯中大型夹杂物类型、尺寸、分布等信息,根据夹杂物变形特征可直观判断其危害性,但其准确度易受其他因素影响。     

EAF-LF(VD)-CC工艺生产石油管线钢39Mn2V 纯净度的分析

分析和研究了EAF-LF(VD)-CC各工序39Mn2V钢的T[O] 和[N] 以及钢中非金属夹杂物。结 果表明,LF(VD) 后T[O] 为28×10^-6,铸坯T[O] 为(8~10)×10^-6 ;钢中夹杂物主要为Al₂O₃、MnS、球形铝酸 钙,尺寸≤20 μm。铸坯存在一些80~300 μm 夹杂物,主要来源于二次氧化、耐火材料侵蚀和结晶器卷渣。     

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。     

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.     

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.     

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。     

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.