85 t VOD精炼超纯铁素体不锈钢的脱氮工艺及效果

分析了85 t VOD精炼时相关工艺参数对超纯铁素体不锈钢00Cr18Mo2和00Cr17Mo终点氮含量的影响。结果表明,随初始碳含量增加,初始氮含量降低,钢水温度提高,适当增加脱氮时间,VOD钢水终点氮含量降低;当控制钢水初始碳含量0.4%～0.9%、处理温度≥1 590℃、真空度≤70 Pa、脱氮时间15～20 min、吹氩搅拌强度8～15 L/(min·t)、初始氮含量≤0.017 0%,VOD终点钢水氮含量为0.006 4%～0.009 5%。     

钢水C、Si含量对VOD精炼不锈钢喷溅的影响

以抚钢二炼钢厂30 t VOD精炼不锈钢的生产数据为依据,分析了入VOD精炼钢水C(0.50%～0.93%)、Si(0.18%～0.42%)含量对喷溅以及吹氧过程温度的影响,证明C、Si含量高(C≥0.65%,Si≥0.22%)是导致吹氧前喷溅事故的主要因素,而C、Si含量低所引起的温升不足又影响后续冶炼的质量和效率。冶炼实践表明,为避免喷溅事故,当钢水[C]≥0.90%或[Si]≥0.40%时不得进行VOD精炼。在VOD吹氧冶炼前钢水中C、Si含量分别为0.40%～0.65%和0.12%～0.20%,能够满足VOD精炼不锈钢的要求。     

含钛铁素体不锈钢精炼过程钛合金化工艺研究

结合含钛铁素体不锈钢工厂试验和热力学计算,研究在VOD还原期、LF精炼前期、LF精炼后期等阶段进行钛合金化时钛的收得率及对钢水质量的影响.结果表明,越靠近精炼结束,钛的收得率越高.VOD还原期进行钛合金化,409L钢的钛收得率为62.7％;在LF精炼后期进行钛合金化,收得率为76％.同时,钛合金化对钢中全氧含量和钢水可...     

30t EAF-LF-VOD/VHD 流程冶炼 MHTlOTa 钢钽含量控制的工艺实践

工业试验和分析了[N]、[O]和钢水温度对MHT10Ta钢钽收得率的影响。9炉工业生产试验结果表明,电弧炉采用氧化法冶炼;LF用C粉脱氧;VOD真空度≤67 Pa,时间≥15 min;进VHD加热,确保Al含量≥0.02%,温度1635~1645℃,Ar气流量100 L/min,按0.125%加入钽条,出钢前按0.01%插入Fe—B,出钢温度1580~1595℃,Ar气保护浇注,MHT10Ta钢成品钽含量0.08%~0.105%,通过工艺优化,钽的收得率可达60%。     

30tEAF-LF-VOD/VHD流程冶炼MHT10Ta钢钽含量控制的工艺实践

工业试验和分析了[N]、[O]和钢水温度对MHT10Ta钢钽收得率的影响。9炉工业生产试验结果表明,电弧炉采用氧化法冶炼;LF用C粉脱氧;VOD真空度≤67 Pa,时间≥15 min;进VHD加热,确保Al含量≥0.02%,温度1635~1645℃,Ar气流量100 L/min,按0.125%加入钽条,出钢前按0.01%插入Fe—B,出钢温度1580~1595℃,Ar气保护浇注,MHT10Ta钢成品钽含量0.08%~0.105%,通过工艺优化,钽的收得率可达60%。     

RH-MFB精炼时钢水温度预报模型的开发

分析研究了RH-MFB精炼时脱碳过程、脱氧、合金化、吹氧加铝、非操作因素对钢水温度的影响,并建立了精炼钢水温度预报模型。通过对连续精炼的10炉270 t超低碳钢水(0.001%~0.0025%C)温度的验证结果表明,模型计算温度和实测温度的误差不大于±5℃。     

30 t VOD精炼含氮不锈钢底吹氮气合金化的生产实践

依据30 t VOD生产数据,在初始[C]0.50%~0.60%,初始[Si]0.12%~0.20%,初始钢水温度1 640~1 650℃,氩和氮气压分别为0.8×10⁶~1.0×10⁶ Pa和1.5×10⁶~1.6×10⁶Pa的条件下,对比底吹氩气和底吹氮气两种工艺在入VOD初始、吹氧脱碳以及还原脱气后的不锈钢（0.04%~0.06%N）中氮含量。结果表明,VOD底吹氮气精炼后Cr13型和Cr17型两类不锈钢的钢液氮含量为260×10^-6和300×10^-6,其氮合金化效果显著;常压下氮气搅拌Cr13型和Cr17型不锈钢钢液的平均增氮速率为40×10^-6/min和45×10^-6/min;钢液温度升高,增氮速率增加,通过降低VOD精炼不锈钢的钢液氧含量,能够提高底吹氮气的氮合金化效果。     

真空感应炉熔炼合金钢时用氮化物增氮的试验研究

分析了真空度、温度和氮化物成分对钢中氮溶解度影响,并在50 k真空感应炉对不同化学成分的合金钢(/%:0.06～0.36C、≤3.23Si、≤2.20Al、≤9.00Cr)进行3种氮化物-氮化硅、氮化锰和氮化铬的增氮试验。结果表明,气相中氮气分压对钢液中氮溶解度影响最大;钢中Ti、Cr提高氮溶解度和氮化物的收得率;增加C含量则降低氮溶解度和氮化物的收得率;钢中含有一定量的铝,可以显著提高氮化物的收得率。40 kPa氩气压力,1 600～1 650℃时在硅钢、结构钢和9%Cr钢中氮化硅、氮化锰、氮化铬的收得率分别为25%～30%、30%～50%、60%～100%。     

钢包精炼工艺对钒氮合金收得率的影响

研究了钢包精炼条件下各种工艺参数对VN合金N、V收得率的影响。结果表明:温度、钢水成分、覆盖剂渣量对VN合金收得率基本没有影响;氧势是关键因素,并得到了N的收得率与氧势的回归关系式。覆盖剂中添加Al2O3、CaF2虽然不影响V、N的最终收得率,但却大大延缓了VN合金进入钢水中的速度。正常条件下,V的收得率稳定保持在95%以上。但当氧势较高时(>100×10-6),钢水中的V会逐渐被氧化。     

RH-MFB精炼过程中钢水温度预测模型

建立了RH—MFB精炼过程中钢水温度的数学模型,通过Delphi程序计算了精炼过程中钢水的温度．结果表明,RHMFB精炼开始阶段,钢水温度急剧下降,前10min降温速率约为3℃·min^-1．加Al吹氧、加合金和真空室内壁初始温度对钢水温度影响较大．采用该模型预测了精炼结束时刻的钢水温度,与生产中钢水温度平均误差在±5℃以内的占80%．     

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.